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															SUPREME COURT OF THE UNITED STATES

															_________________

															No. 16–402

															_________________

															TIMOTHY IVORY CARPENTER, PETITIONER v. UNITED STATES

															on writ of certiorari to the united states
court of appeals for the sixth circuit

															[June 22, 2018]

															Chief Justice Roberts delivered the opinion of
the Court.

															This case presents the question whether the
Government conducts a search under the Fourth Amendment when it
accesses historical cell phone records that provide a comprehensive
chronicle of the user’s past movements.

															I

															A

															There are 396 million cell phone service
accounts in the United States—for a Nation of 326 million people.
Cell phones perform their wide and growing variety of functions by
connecting to a set of radio antennas called “cell sites.” Although
cell sites are usually mounted on a tower, they can also be found
on light posts, flagpoles, church steeples, or the sides of
buildings. Cell sites typically have several directional antennas
that divide the covered area into sectors.

															Cell phones continuously scan their environment
looking for the best signal, which generally comes from the closest
cell site. Most modern devices, such as smartphones, tap into the
wireless network several times a minute whenever their signal is
on, even if the owner is not using one of the phone’s features.
Each time the phone connects to a cell site, it generates a
time-stamped record known as cell-site location information (CSLI).
The precision of this information depends on the size of the
geographic area covered by the cell site. The greater the
concentration of cell sites, the smaller the coverage area. As data
usage from cell phones has increased, wireless carriers have
installed more cell sites to handle the traffic. That has led to
increasingly compact coverage areas, especially in urban areas.

															Wireless carriers collect and store CSLI for
their own business purposes, including finding weak spots in their
network and applying “roaming” charges when another carrier routes
data through their cell sites. In addition, wireless carriers often
sell aggregated location records to data brokers, without
individual identifying information of the sort at issue here. While
carriers have long retained CSLI for the start and end of incoming
calls, in recent years phone companies have also collected location
information from the transmission of text messages and routine data
connections. Accordingly, modern cell phones generate increasingly
vast amounts of increasingly precise CSLI.

															B

															In 2011, police officers arrested four men
suspected of robbing a series of Radio Shack and (ironically
enough) T-Mobile stores in Detroit. One of the men confessed that,
over the previous four months, the group (along with a rotating
cast of getaway drivers and lookouts) had robbed nine different
stores in Michigan and Ohio. The suspect identified 15 accomplices
who had participated in the heists and gave the FBI some of their
cell phone numbers; the FBI then reviewed his call records to
identify additional numbers that he had called around the time of
the robberies.

															Based on that information, the prosecutors
applied for court orders under the Stored Communications Act to
obtain cell phone records for petitioner Timothy Carpenter and
several other suspects. That statute, as amended in 1994, permits
the Government to compel the disclosure of certain
telecommunications records when it “offers specific and articulable
facts showing that there are reasonable grounds to believe” that
the records sought “are relevant and material to an ongoing
criminal investigation.” 18 U. S. C. §2703(d). Federal
Magistrate Judges issued two orders directing Carpenter’s wireless
carriers—MetroPCS and Sprint—to disclose “cell/site sector
[information] for [Carpenter’s] telephone[ ] at call origination
and at call termination for incoming and outgoing calls” during the
four-month period when the string of robberies occurred. App. to
Pet. for Cert. 60a, 72a. The first order sought 152 days of
cell-site records from MetroPCS, which produced records spanning
127 days. The second order requested seven days of CSLI from
Sprint, which produced two days of records covering the period when
Carpenter’s phone was “roaming” in northeastern Ohio. Altogether
the Government obtained 12,898 location points cataloging
Carpenter’s movements—an average of 101 data points per day.

															Carpenter was charged with six counts of robbery
and an additional six counts of carrying a firearm during a federal
crime of violence. See 18 U. S. C. §§924(c), 1951(a).
Prior to trial, Carpenter moved to suppress the cell-site data
provided by the wireless carriers. He argued that the Government’s
seizure of the records violated the Fourth Amendment because they
had been obtained without a warrant supported by probable cause.
The District Court denied the motion. App. to Pet. for Cert.
38a–39a.

															At trial, seven of Carpenter’s confederates
pegged him as the leader of the operation. In addition, FBI agent
Christopher Hess offered expert testimony about the cell-site data.
Hess explained that each time a cell phone taps into the wireless
network, the carrier logs a time-stamped record of the cell site
and particular sector that were used. With this information, Hess
produced maps that placed Carpenter’s phone near four of the
charged robberies. In the Government’s view, the location records
clinched the case: They confirmed that Carpenter was “right where
the . . . robbery was at the exact time of the robbery.”
App. 131 (closing argument). Carpenter was convicted on all but one
of the firearm counts and sentenced to more than 100 years in
prison.

															The Court of Appeals for the Sixth Circuit
affirmed. 819 F. 3d 880 (2016). The court held that Carpenter
lacked a reasonable expectation of privacy in the location
information collected by the FBI because he had shared that
information with his wireless carriers. Given that cell phone users
voluntarily convey cell-site data to their carriers as “a means of
establishing communication,” the court concluded that the resulting
business records are not entitled to Fourth Amendment protection. Id., at 888 (quoting Smith v. Maryland , 442
U. S. 735, 741 (1979)).

															We granted certiorari. 582 U. S. ___
(2017).

															II

															A

															The Fourth Amendment protects “[t]he right of
the people to be secure in their persons, houses, papers, and
effects, against unreasonable searches and seizures.” The “basic
purpose of this Amendment,” our cases have recognized, “is to
safeguard the privacy and security of individuals against arbitrary
invasions by governmental officials.” Camara v. Municipal
Court of City and County of San Francisco , 387 U. S. 523,
528 (1967). The Founding generation crafted the Fourth Amendment as
a “response to the reviled ‘general warrants’ and ‘writs of
assistance’ of the colonial era, which allowed British officers to
rummage through homes in an unrestrained search for evidence of
criminal activity.” Riley v. California , 573
U. S. ___, ___ (2014) (slip op., at 27). In fact, as John
Adams recalled, the patriot James Otis’s 1761 speech condemning
writs of assistance was “the first act of opposition to the
arbitrary claims of Great Britain” and helped spark the Revolution
itself. Id., at ___–___ (slip op., at 27–28) (quoting 10
Works of John Adams 248 (C. Adams ed. 1856)).

															For much of our history, Fourth Amendment search
doctrine was “tied to common-law trespass” and focused on whether
the Government “obtains information by physically intruding on a
constitutionally protected area.” United States v. Jones , 565 U. S. 400, 405, 406, n. 3 (2012). More
recently, the Court has recognized that “property rights are not
the sole measure of Fourth Amendment violations.” Soldal v. Cook County , 506 U. S. 56, 64 (1992). In Katz v. United States , 389 U. S. 347, 351 (1967), we
established that “the Fourth Amendment protects people, not
places,” and expanded our conception of the Amendment to protect
certain expectations of privacy as well. When an individual “seeks
to preserve something as private,” and his expectation of privacy
is “one that society is prepared to recognize as reasonable,” we
have held that official intrusion into that private sphere
generally qualifies as a search and requires a warrant supported by
probable cause. Smith , 442 U. S., at 740 (internal
quotation marks and alterations omitted).

															Although no single rubric definitively resolves
which expectations of privacy are entitled to protection,[ 1 ] the analysis is informed by
historical understandings “of what was deemed an unreasonable
search and seizure when [the Fourth Amendment] was adopted.” Carroll v. United States , 267 U. S. 132, 149
(1925). On this score, our cases have recognized some basic
guideposts. First, that the Amendment seeks to secure “the
privacies of life” against “arbitrary power.” Boyd v. United States , 116 U. S. 616, 630 (1886). Second, and
relatedly, that a central aim of the Framers was “to place
obstacles in the way of a too permeating police surveillance.” United States v. Di Re , 332 U. S. 581, 595
(1948).

															We have kept this attention to Founding-era
understandings in mind when applying the Fourth Amendment to
innovations in surveillance tools. As technology has enhanced the
Government’s capacity to encroach upon areas normally guarded from
inquisitive eyes, this Court has sought to “assure[ ] preservation
of that degree of privacy against government that existed when the
Fourth Amendment was adopted.” Kyllo v. United
States , 533 U. S. 27, 34 (2001). For that reason, we
rejected in Kyllo a “mechanical interpretation” of the
Fourth Amendment and held that use of a thermal imager to detect
heat radiating from the side of the defendant’s home was a search. Id., at 35. Because any other conclusion would leave
homeowners “at the mercy of advancing technology,” we determined
that the Government—absent a warrant—could not capitalize on such
new sense-enhancing technology to explore what was happening within
the home. Ibid. Likewise in Riley , the Court recognized
the “immense storage capacity” of modern cell phones in holding
that police officers must generally obtain a warrant before
searching the contents of a phone. 573 U. S., at ___ (slip
op., at 17). We explained that while the general rule allowing
warrantless searches incident to arrest “strikes the appropriate
balance in the context of physical objects, neither of its
rationales has much force with respect to” the vast store of
sensitive information on a cell phone. Id. , at ___ (slip
op., at 9).

															B

															The case before us involves the Government’s
acquisition of wireless carrier cell-site records revealing the
location of Carpenter’s cell phone whenever it made or received
calls. This sort of digital data—personal location information
maintained by a third party—does not fit neatly under existing
precedents. Instead, requests for cell-site records lie at the
intersection of two lines of cases, both of which inform our
understanding of the privacy interests at stake.

															The first set of cases addresses a person’s
expectation of privacy in his physical location and movements. In United States v. Knotts , 460 U. S. 276 (1983),
we considered the Government’s use of a “beeper” to aid in tracking
a vehicle through traffic. Police officers in that case planted a
beeper in a container of chloroform before it was purchased by one
of Knotts’s co-conspirators. The officers (with intermittent aerial
assistance) then followed the automobile carrying the container
from Minneapolis to Knotts’s cabin in Wisconsin, relying on the
beeper’s signal to help keep the vehicle in view. The Court
concluded that the “augment[ed]” visual surveillance did not
constitute a search because “[a] person traveling in an automobile
on public thoroughfares has no reasonable expectation of privacy in
his movements from one place to another.” Id., at 281, 282.
Since the movements of the vehicle and its final destination had
been “voluntarily conveyed to anyone who wanted to look,” Knotts
could not assert a privacy interest in the information obtained. Id., at 281.

															This Court in Knotts , however, was
careful to distinguish between the rudimentary tracking facilitated
by the beeper and more sweeping modes of surveillance. The Court
emphasized the “limited use which the government made of the
signals from this particular beeper” during a discrete “automotive
journey.” Id., at 284, 285. Significantly, the Court
reserved the question whether “different constitutional principles
may be applicable” if “twenty-four hour surveillance of any citizen
of this country [were] possible.” Id., at 283–284.

															Three decades later, the Court considered more
sophisticated surveillance of the sort envisioned in Knotts and found that different principles did indeed apply. In United
States v. Jones , FBI agents installed a GPS tracking
device on Jones’s vehicle and remotely monitored the vehicle’s
movements for 28 days. The Court decided the case based on the
Government’s physical trespass of the vehicle. 565 U. S., at
404–405. At the same time, five Justices agreed that related
privacy concerns would be raised by, for example, “surreptitiously
activating a stolen vehicle detection system” in Jones’s car to
track Jones himself, or conducting GPS tracking of his cell phone. Id. , at 426, 428 (Alito, J., concurring in judgment); id., at 415 (Sotomayor, J., concurring). Since GPS
monitoring of a vehicle tracks “every movement” a person makes in
that vehicle, the concurring Justices concluded that “longer term
GPS monitoring in investigations of most offenses impinges on
expectations of privacy”—regardless whether those movements were
disclosed to the public at large. Id., at 430 (opinion of
Alito, J.); id., at 415 (opinion of Sotomayor, J.).[ 2 ]

															In a second set of decisions, the Court has
drawn a line between what a person keeps to himself and what he
shares with others. We have previously held that “a person has no
legitimate expectation of privacy in information he voluntarily
turns over to third parties.” Smith, 442 U. S., at
743–744. That remains true “even if the information is revealed on
the assumption that it will be used only for a limited purpose.” United States v. Miller , 425 U. S. 435, 443
(1976). As a result, the Government is typically free to obtain
such information from the recipient without triggering Fourth
Amendment protections.

															This third-party doctrine largely traces its
roots to Miller . While investigating Miller for tax evasion,
the Government subpoenaed his banks, seeking several months of
canceled checks, deposit slips, and monthly statements. The Court
rejected a Fourth Amendment challenge to the records collection.
For one, Miller could “assert neither ownership nor possession” of
the documents; they were “business records of the banks.” Id., at 440. For another, the nature of those records
confirmed Miller’s limited expectation of privacy, because the
checks were “not confidential communications but negotiable
instruments to be used in commercial transactions,” and the bank
statements contained information “exposed to [bank] employees in
the ordinary course of business.” Id., at 442. The Court
thus concluded that Miller had “take[n] the risk, in revealing his
affairs to another, that the information [would] be conveyed by
that person to the Government.” Id., at 443.

															Three years later, Smith applied the same
principles in the context of information conveyed to a telephone
com- pany. The Court ruled that the Government’s use of a pen
register—a device that recorded the outgoing phone numbers dialed
on a landline telephone—was not a search. Noting the pen register’s
“limited capabilities,” the Court “doubt[ed] that people in general
entertain any actual expectation of privacy in the numbers they
dial.” 442 U. S., at 742. Telephone subscribers know, after
all, that the numbers are used by the telephone company “for a
variety of legitimate business purposes,” including routing calls. Id., at 743. And at any rate, the Court explained, such an
expectation “is not one that society is prepared to recognize as
reasonable.” Ibid. (internal quotation marks omitted). When
Smith placed a call, he “voluntarily conveyed” the dialed numbers
to the phone company by “expos[ing] that information to its
equipment in the ordinary course of business.” Id., at 744
(internal quotation marks omitted). Once again, we held that the
defendant “assumed the risk” that the company’s records “would be
divulged to police.” Id., at 745.

															III

															The question we confront today is how to apply
the Fourth Amendment to a new phenomenon: the ability to chronicle
a person’s past movements through the record of his cell phone
signals. Such tracking partakes of many of the qualities of the GPS
monitoring we considered in Jones . Much like GPS tracking of
a vehicle, cell phone location information is detailed,
encyclopedic, and effortlessly compiled.

															At the same time, the fact that the individual
continuously reveals his location to his wireless carrier
implicates the third-party principle of Smith and Miller . But while the third-party doctrine applies to
telephone numbers and bank records, it is not clear whether its
logic extends to the qualitatively different category of cell-site
records. After all, when Smith was decided in 1979, few
could have imagined a society in which a phone goes wherever its
owner goes, conveying to the wireless carrier not just dialed
digits, but a detailed and comprehensive record of the person’s
movements.

															We decline to extend Smith and Miller to cover these novel circumstances. Given the unique
nature of cell phone location records, the fact that the
information is held by a third party does not by itself overcome
the user’s claim to Fourth Amendment protection. Whether the
Government employs its own surveillance technology as in Jones or leverages the technology of a wireless carrier, we
hold that an individual maintains a legitimate expectation of
privacy in the record of his physical movements as captured through
CSLI. The location information obtained from Carpenter’s wireless
carriers was the product of a search.[ 3 ]

															A

															A person does not surrender all Fourth
Amendment protection by venturing into the public sphere. To the
contrary, “what [one] seeks to preserve as private, even in an area
accessible to the public, may be constitutionally protected.” Katz , 389 U. S., at 351–352. A majority of this Court
has already recognized that individuals have a reasonable
expectation of privacy in the whole of their physical movements. Jones , 565 U. S., at 430 (Alito, J., concurring in
judgment); id., at 415 (Sotomayor, J., concurring). Prior to
the digital age, law enforcement might have pursued a suspect for a
brief stretch, but doing so “for any extended period of time was
difficult and costly and therefore rarely undertaken.” Id., at 429 (opinion of Alito, J.). For that reason, “society’s
expectation has been that law enforcement agents and others would
not—and indeed, in the main, simply could not—secretly monitor and
catalogue every single movement of an individual’s car for a very
long period.” Id. , at 430.

															Allowing government access to cell-site records
contravenes that expectation. Although such records are generated
for commercial purposes, that distinction does not negate
Carpenter’s anticipation of privacy in his physical location.
Mapping a cell phone’s location over the course of 127 days
provides an all-encompassing record of the holder’s whereabouts. As
with GPS information, the time-stamped data provides an intimate
window into a person’s life, revealing not only his particular
movements, but through them his “familial, political, professional,
religious, and sexual associations.” Id., at 415 (opinion of
Sotomayor, J.). These location records “hold for many Americans the
‘privacies of life.’ ” Riley , 573 U. S., at ___
(slip op., at 28) (quoting Boyd , 116 U. S., at 630).
And like GPS monitoring, cell phone tracking is remarkably easy,
cheap, and efficient compared to traditional investigative tools.
With just the click of a button, the Government can access each
carrier’s deep repository of historical location information at
practically no expense.

															In fact, historical cell-site records present
even greater privacy concerns than the GPS monitoring of a vehicle
we considered in Jones . Unlike the bugged container in Knotts or the car in Jones , a cell phone—almost a
“feature of human anatomy,” Riley , 573 U. S., at ___
(slip op., at 9)—tracks nearly exactly the movements of its owner.
While individuals regularly leave their vehicles, they compulsively
carry cell phones with them all the time. A cell phone faithfully
follows its owner beyond public thoroughfares and into private
residences, doctor’s offices, political headquarters, and other
potentially revealing locales. See id. , at ___ (slip op., at
19) (noting that “nearly three-quarters of smart phone users report
being within five feet of their phones most of the time, with 12%
admitting that they even use their phones in the shower”); contrast Cardwell v. Lewis , 417 U. S. 583, 590 (1974)
(plurality opinion) (“A car has little capacity for escaping public
scrutiny.”). Accordingly, when the Government tracks the location
of a cell phone it achieves near perfect surveillance, as if it had
attached an ankle monitor to the phone’s user.

															Moreover, the retrospective quality of the data
here gives police access to a category of information otherwise
unknowable. In the past, attempts to reconstruct a person’s
movements were limited by a dearth of records and the frailties of
recollection. With access to CSLI, the Government can now travel
back in time to retrace a person’s whereabouts, subject only to the
retention polices of the wireless carriers, which currently
maintain records for up to five years. Critically, because location
information is continually logged for all of the 400 million
devices in the United States—not just those belonging to persons
who might happen to come under investigation—this newfound tracking
capacity runs against everyone. Unlike with the GPS device in Jones , police need not even know in advance whether they
want to follow a particular individual, or when.

															Whoever the suspect turns out to be, he has
effectively been tailed every moment of every day for five years,
and the police may—in the Government’s view—call upon the results
of that surveillance without regard to the constraints of the
Fourth Amendment. Only the few with- out cell phones could escape
this tireless and absolute surveillance.

															The Government and Justice Kennedy contend,
however, that the collection of CSLI should be permitted because
the data is less precise than GPS information. Not to worry, they
maintain, because the location records did “not on their own
suffice to place [Carpenter] at the crime scene”; they placed him
within a wedge-shaped sector ranging from one-eighth to four square
miles. Brief for United States 24; see post, at 18–19. Yet
the Court has already rejected the proposition that “inference
insulates a search.” Kyllo , 533 U. S., at 36. From the
127 days of location data it received, the Government could, in
combination with other information, deduce a detailed log of
Carpenter’s movements, including when he was at the site of the
robberies. And the Government thought the CSLI accurate enough to
highlight it during the closing argument of his trial. App.
131.

															At any rate, the rule the Court adopts “must
take account of more sophisticated systems that are already in use
or in development.” Kyllo , 533 U. S., at 36. While the
records in this case reflect the state of technology at the start
of the decade, the accuracy of CSLI is rapidly approaching
GPS-level precision. As the number of cell sites has proliferated,
the geographic area covered by each cell sector has shrunk,
particularly in urban areas. In addition, with new technology
measuring the time and angle of signals hitting their towers,
wireless carriers already have the capability to pinpoint a phone’s
location within 50 meters. Brief for Electronic Frontier Foundation
et al. as Amici Curiae 12 (describing triangulation
methods that estimate a device’s location inside a given cell
sector).

															Accordingly, when the Government accessed CSLI
from the wireless carriers, it invaded Carpenter’s reason- able
expectation of privacy in the whole of his physical movements.

															B

															The Government’s primary contention to the
contrary is that the third-party doctrine governs this case. In its
view, cell-site records are fair game because they are “business
records” created and maintained by the wireless carriers. The
Government (along with Justice Kennedy) recognizes that this case
features new technology, but asserts that the legal question
nonetheless turns on a garden-variety request for information from
a third-party witness. Brief for United States 32–34; post, at 12–14.

															The Government’s position fails to contend with
the seismic shifts in digital technology that made possible the
tracking of not only Carpenter’s location but also everyone else’s,
not for a short period but for years and years. Sprint Corporation
and its competitors are not your typical witnesses. Unlike the nosy
neighbor who keeps an eye on comings and goings, they are ever
alert, and their memory is nearly infallible. There is a world of
difference between the limited types of personal information
addressed in Smith and Miller and the exhaustive
chronicle of location information casually collected by wireless
carriers today. The Government thus is not asking for a
straightforward application of the third-party doctrine, but
instead a significant extension of it to a distinct category of
information.

															The third-party doctrine partly stems from the
notion that an individual has a reduced expectation of privacy in
information knowingly shared with another. But the fact of
“diminished privacy interests does not mean that the Fourth
Amendment falls out of the picture entirely.” Riley , 573
U. S., at ___ (slip op., at 16). Smith and Miller , after all, did not rely solely on the act of
sharing. Instead, they considered “the nature of the particular
documents sought” to determine whether “there is a legitimate
‘expectation of privacy’ concerning their contents.” Miller ,
425 U. S., at 442. Smith pointed out the limited
capabilities of a pen register; as explained in Riley ,
telephone call logs reveal little in the way of “identifying
information.” Smith , 442 U. S., at 742; Riley ,
573 U. S., at ___ (slip op., at 24). Miller likewise
noted that checks were “not confidential communications but
negotiable instruments to be used in commercial transactions.” 425
U. S., at 442. In mechanically applying the third-party
doctrine to this case, the Government fails to appreciate that
there are no comparable limitations on the revealing nature of
CSLI.

															The Court has in fact already shown special
solicitude for location information in the third-party context. In Knotts , the Court relied on Smith to hold that an
individual has no reasonable expectation of privacy in public
movements that he “voluntarily conveyed to anyone who wanted to
look.” Knotts , 460 U. S., at 281; see id. , at
283 (discussing Smith ). But when confronted with more
pervasive tracking, five Justices agreed that longer term GPS
monitoring of even a vehicle traveling on public streets
constitutes a search. Jones , 565 U. S., at 430 (Alito,
J., concurring in judgment); id. , at 415 (Sotomayor, J.,
concurring). Justice Gorsuch wonders why “someone’s location when
using a phone” is sensitive, post, at 3, and Justice Kennedy
assumes that a person’s discrete movements “are not particularly
private,” post, at 17. Yet this case is not about “using a
phone” or a person’s movement at a particular time. It is about a
detailed chronicle of a person’s physical presence compiled every
day, every moment, over several years. Such a chronicle implicates
privacy concerns far beyond those considered in Smith and Miller .

															Neither does the second rationale underlying the
third-party doctrine—voluntary exposure—hold up when it comes to
CSLI. Cell phone location information is not truly “shared” as one
normally understands the term. In the first place, cell phones and
the services they provide are “such a pervasive and insistent part
of daily life” that carrying one is indispensable to participation
in modern society. Riley , 573 U. S., at ___ (slip op.,
at 9). Second, a cell phone logs a cell-site record by dint of its
operation, without any affirmative act on the part of the user
beyond powering up. Virtually any activity on the phone generates
CSLI, including incoming calls, texts, or e-mails and countless
other data connections that a phone automatically makes when
checking for news, weather, or social media updates. Apart from
disconnecting the phone from the network, there is no way to avoid
leaving behind a trail of location data. As a result, in no
meaningful sense does the user voluntarily “assume[ ] the
risk” of turning over a comprehensive dossier of his physical
movements. Smith , 442 U. S., at 745.

															We therefore decline to extend Smith and Miller to the collection of CSLI. Given the unique nature of
cell phone location information, the fact that the Government
obtained the information from a third party does not overcome
Carpenter’s claim to Fourth Amendment protection. The Government’s
acquisition of the cell-site records was a search within the
meaning of the Fourth Amendment.

															*  *  *

															Our decision today is a narrow one. We do not
express a view on matters not before us: real-time CSLI or “tower
dumps” (a download of information on all the devices that connected
to a particular cell site during a particular interval). We do not
disturb the application of Smith and Miller or call
into question conventional surveillance techniques and tools, such
as security cameras. Nor do we address other business records that
might incidentally reveal location information. Further, our
opinion does not consider other collection techniques involving
foreign affairs or national security. As Justice Frankfurter noted
when considering new innovations in airplanes and radios, the Court
must tread carefully in such cases, to ensure that we do not
“embarrass the future.” Northwest Airlines, Inc. v. Minnesota , 322 U. S. 292, 300 (1944).[ 4 ]

															IV

															Having found that the acquisition of
Carpenter’s CSLI was a search, we also conclude that the Government
must generally obtain a warrant supported by probable cause before
acquiring such records. Although the “ultimate measure of the
constitutionality of a governmental search is
‘reasonableness,’ ” our cases establish that warrantless
searches are typically unreasonable where “a search is undertaken
by law enforcement officials to discover evidence of criminal
wrongdoing.” Vernonia School Dist. 47J v. Acton , 515
U. S. 646, 652–653 (1995). Thus, “[i]n the absence of a
warrant, a search is reasonable only if it falls within a specific
exception to the warrant requirement.” Riley , 573
U. S., at ___ (slip op., at 5).

															The Government acquired the cell-site records
pursuant to a court order issued under the Stored Communications
Act, which required the Government to show “reasonable grounds” for
believing that the records were “relevant and material to an
ongoing investigation.” 18 U. S. C. §2703(d). That
showing falls well short of the probable cause required for a
warrant. The Court usually requires “some quantum of individualized
suspicion” before a search or seizure may take place. United
States v. Martinez-Fuerte , 428 U. S. 543, 560–561
(1976). Under the standard in the Stored Communications Act,
however, law enforcement need only show that the cell-site evidence
might be pertinent to an ongoing investigation—a “gigantic”
departure from the probable cause rule, as the Government explained
below. App. 34. Consequently, an order issued under Section 2703(d)
of the Act is not a permissible mechanism for accessing historical
cell-site records. Before compelling a wireless carrier to turn
over a subscriber’s CSLI, the Government’s obligation is a familiar
one—get a warrant.

															Justice Alito contends that the warrant
requirement simply does not apply when the Government acquires
records using compulsory process. Unlike an actual search, he says,
subpoenas for documents do not involve the direct taking of
evidence; they are at most a “constructive search” conducted by the
target of the subpoena. Post, at 12. Given this lesser
intrusion on personal privacy, Justice Alito argues that the
compulsory production of records is not held to the same probable
cause standard. In his view, this Court’s precedents set forth a
categorical rule—separate and distinct from the third-party
doctrine—subjecting subpoenas to lenient scrutiny without regard to
the suspect’s expectation of privacy in the records. Post, at 8–19.

															But this Court has never held that the
Government may subpoena third parties for records in which the
suspect has a reasonable expectation of privacy. Almost all of the
examples Justice Alito cites, see post, at 14–15,
contemplated requests for evidence implicating diminished pri- vacy
interests or for a corporation’s own books.[ 5 ] The lone exception, of course, is Miller ,
where the Court’s analysis of the third-party subpoena merged with
the application of the third-party doctrine. 425 U. S., at 444
(concluding that Miller lacked the necessary privacy interest to
contest the issuance of a subpoena to his bank).

															Justice Alito overlooks the critical issue. At
some point, the dissent should recognize that CSLI is an entirely
different species of business record—something that implicates
basic Fourth Amendment concerns about arbitrary government power
much more directly than corporate tax or payroll ledgers. When
confronting new concerns wrought by digital technology, this Court
has been careful not to uncritically extend existing precedents.
See Riley , 573 U. S., at ___ (slip op., at 10) (“A
search of the information on a cell phone bears little resemblance
to the type of brief physical search considered [in prior
precedents].”).

															If the choice to proceed by subpoena provided a
categorical limitation on Fourth Amendment protection, no type of
record would ever be protected by the warrant requirement. Under
Justice Alito’s view, private letters, digital contents of a cell
phone—any personal information reduced to document form, in
fact—may be collected by subpoena for no reason other than
“official curiosity.” United States v. Morton Salt
Co. , 338 U. S. 632, 652 (1950). Justice Kennedy declines
to adopt the radical implications of this theory, leaving open the
question whether the warrant requirement applies “when the
Government obtains the modern-day equivalents of an individual’s
own ‘papers’ or ‘effects,’ even when those papers or effects are
held by a third party. ” Post, at 13 (citing United
States v. Warshak , 631 F. 3d 266, 283–288 (CA6
2010)). That would be a sensible exception, because it would
prevent the subpoena doctrine from overcoming any reasonable
expectation of privacy. If the third-party doctrine does not apply
to the “modern-day equivalents of an individual’s own ‘papers’ or
‘effects,’ ” then the clear implication is that the documents
should receive full Fourth Amendment protection. We simply think
that such protection should extend as well to a detailed log of a
person’s movements over several years.

															This is certainly not to say that all orders
compelling the production of documents will require a showing of
probable cause. The Government will be able to use subpoenas to
acquire records in the overwhelming majority of investigations. We
hold only that a warrant is required in the rare case where the
suspect has a legitimate privacy interest in records held by a
third party.

															Further, even though the Government will
generally need a warrant to access CSLI, case-specific exceptions
may support a warrantless search of an individual’s cell-site
records under certain circumstances. “One well-recognized exception
applies when ‘ “the exigencies of the situation” make the
needs of law enforcement so compelling that [a] warrantless search
is objectively reasonable under the Fourth Amendment.’ ” Kentucky v. King , 563 U. S. 452, 460 (2011)
(quoting Mincey v. Arizona , 437 U. S. 385, 394
(1978)). Such exigencies include the need to pursue a fleeing
suspect, protect individuals who are threatened with imminent harm,
or prevent the imminent destruction of evidence. 563 U. S., at
460, and n. 3.

															As a result, if law enforcement is confronted
with an urgent situation, such fact-specific threats will likely
justify the warrantless collection of CSLI. Lower courts, for
instance, have approved warrantless searches related to bomb
threats, active shootings, and child abductions. Our decision today
does not call into doubt warrantless access to CSLI in such
circumstances. While police must get a warrant when collecting CSLI
to assist in the mine-run criminal investigation, the rule we set
forth does not limit their ability to respond to an ongoing
emergency.

															*  *  *

															As Justice Brandeis explained in his famous
dissent, the Court is obligated—as “[s]ubtler and more far-reaching
means of invading privacy have become available to the
Government”—to ensure that the “progress of science” does not erode
Fourth Amendment protections. Olmstead v. United
States , 277 U. S. 438, 473–474 (1928). Here the progress
of science has afforded law enforcement a powerful new tool to
carry out its important responsibilities. At the same time, this
tool risks Government encroachment of the sort the Framers, “after
consulting the lessons of history,” drafted the Fourth Amendment to
prevent. Di Re , 332 U. S., at 595.

															We decline to grant the state unrestricted
access to a wireless carrier’s database of physical location
information. In light of the deeply revealing nature of CSLI, its
depth, breadth, and comprehensive reach, and the inescapable and
automatic nature of its collection, the fact that such information
is gathered by a third party does not make it any less deserving of
Fourth Amendment protection. The Government’s acquisition of the
cell-site records here was a search under that Amendment.

															The judgment of the Court of Appeals is
reversed, and the case is remanded for further proceedings
consistent with this opinion.

															It is so ordered. Notes 1 Justice Kennedy believes
that there is such a rubric—the “property-based concepts” that Katz purported to move beyond. Post, at 3 (dissenting
opinion). But while property rights are often informative, our
cases by no means suggest that such an interest is “fundamental” or
“dispositive” in determining which expectations of privacy are
legitimate. Post, at 8–9. Justice Thomas (and to a large
extent Justice Gorsuch) would have us abandon Katz and
return to an exclusively property-based approach. Post, at
1–2, 17–21 (Thomas J., dissenting); post, at 6–9 (Gorsuch,
J., dissenting). Katz of course “discredited” the “premise
that property interests control,” 389 U. S., at 353, and we
have repeatedly emphasized that privacy interests do not rise or
fall with property rights, see, e.g., United States v. Jones , 565 U. S. 400, 411 (2012) (refusing to “make
trespass the exclusive test”); Kyllo v. United
States , 533 U. S. 27, 32 (2001) (“We have since decoupled
violation of a person’s Fourth Amendment rights from trespassory
violation of his property.”). Neither party has asked the Court to
reconsider Katz in this case. 2 Justice Kennedy argues
that this case is in a different category from Jones and the
dragnet-type practices posited in Knotts because the
disclosure of the cell-site records was subject to “judicial
authorization.” Post , at 14–16. That line of argument
conflates the threshold question whether a “search” has occurred
with the separate matter of whether the search was reasonable. The
subpoena process set forth in the Stored Communications Act does
not determine a target’s expectation of privacy. And in any event,
neither Jones nor Knotts purported to resolve the
question of what authorization may be required to conduct such
electronic surveillance techniques. But see Jones , 565
U. S., at 430 (Alito, J., concurring in judgment) (indicating
that longer term GPS tracking may require a warrant). 3 The parties suggest as an
alternative to their primary submissions that the acquisition of
CSLI becomes a search only if it extends beyond a limited period.
See Reply Brief 12 (proposing a 24-hour cutoff); Brief for United
States 55–56 (suggesting a seven-day cutoff). As part of its
argument, the Government treats the seven days of CSLI requested
from Sprint as the pertinent period, even though Sprint produced
only two days of records. Brief for United States 56. Contrary to
Justice Kennedy’s assertion, post, at 19, we need not decide
whether there is a limited period for which the Government may
obtain an individual’s historical CSLI free from Fourth Amendment
scrutiny, and if so, how long that period might be. It is
sufficient for our purposes today to hold that accessing seven days
of CSLI constitutes a Fourth Amendment search. 4 Justice Gorsuch faults us
for not promulgating a complete code addressing the manifold
situations that may be presented by this new technology—under a
constitutional provision turning on what is “reasonable,” no less. Post, at 10–12. Like Justice Gorsuch, we “do not begin to
claim all the answers today,” post, at 13, and therefore
decide no more than the case before us. 5 See United States v. Dionisio , 410 U. S. 1, 14 (1973) (“No person can
have a reasonable expectation that others will not know the sound
of his voice”); Donovan v. Lone Steer, Inc. , 464
U. S. 408, 411, 415 (1984) (payroll and sales records); California Bankers Assn. v. Shultz , 416 U. S.
21, 67 (1974) (Bank Secrecy Act reporting requirements); See v. Seattle , 387 U. S. 541, 544 (1967) (financial books
and records); United States v. Powell , 379 U. S.
48, 49, 57 (1964) (corporate tax records); McPhaul v. United States , 364 U. S. 372, 374, 382 (1960) (books
and records of an organization); United States v. Morton
Salt Co. , 338 U. S. 632, 634, 651–653 (1950) (Federal
Trade Commission reporting requirement); Oklahoma Press
Publishing Co. v. Walling , 327 U. S. 186, 189,
204–208 (1946) (payroll records); Hale v. Henkel , 201
U. S. 43, 45, 75 (1906) (corporate books and
papers). SUPREME COURT OF THE UNITED STATES

															_________________

															No. 16–402

															_________________

															TIMOTHY IVORY CARPENTER, PETITIONER v. UNITED STATES

															on writ of certiorari to the united states
court of appeals for the sixth circuit

															[June 22, 2018]

															Justice Kennedy, with whom Justice Thomas and
Justice Alito join, dissenting.

															This case involves new technology, but the
Court’s stark departure from relevant Fourth Amendment precedents
and principles is, in my submission, unnecessary and incorrect,
requiring this respectful dissent.

															The new rule the Court seems to formulate puts
needed, reasonable, accepted, lawful, and congressionally
authorized criminal investigations at serious risk in serious
cases, often when law enforcement seeks to prevent the threat of
violent crimes. And it places undue restrictions on the lawful and
necessary enforcement powers exercised not only by the Federal
Government, but also by law enforcement in every State and locality
throughout the Nation. Adherence to this Court’s longstanding
precedents and analytic framework would have been the proper and
prudent way to resolve this case.

															The Court has twice held that individuals have
no Fourth Amendment interests in business records which are
possessed, owned, and controlled by a third party. United
States v. Miller , 425 U. S. 435 (1976); Smith v. Maryland , 442 U. S. 735 (1979). This is
true even when the records contain personal and sensitive
information. So when the Government uses a subpoena to obtain, for
example, bank records, telephone records, and credit card
statements from the businesses that create and keep these records,
the Government does not engage in a search of the business’s
customers within the meaning of the Fourth Amendment.

															In this case petitioner challenges the
Government’s right to use compulsory process to obtain a now-common
kind of business record: cell-site records held by cell phone
service providers. The Government acquired the records through an
investigative process enacted by Congress. Upon approval by a
neutral magistrate, and based on the Government’s duty to show
reasonable necessity, it authorizes the disclosure of records and
information that are under the control and ownership of the cell
phone service provider, not its customer. Petitioner acknowledges
that the Government may obtain a wide variety of business records
using compulsory process, and he does not ask the Court to revisit
its precedents. Yet he argues that, under those same precedents,
the Government searched his records when it used court-approved
compulsory process to obtain the cell-site information at issue
here.

															Cell-site records, however, are no different
from the many other kinds of business records the Government has a
lawful right to obtain by compulsory process. Customers like
petitioner do not own, possess, control, or use the records, and
for that reason have no reasonable expectation that they cannot be
disclosed pursuant to lawful compulsory process.

															The Court today disagrees. It holds for the
first time that by using compulsory process to obtain records of a
business entity, the Government has not just engaged in an
impermissible action, but has conducted a search of the business’s
customer. The Court further concludes that the search in this case
was unreasonable and the Government needed to get a warrant to
obtain more than six days of cell-site records.

															In concluding that the Government engaged in a
search, the Court unhinges Fourth Amendment doctrine from the
property-based concepts that have long grounded the analytic
framework that pertains in these cases. In doing so it draws an
unprincipled and unworkable line between cell-site records on the
one hand and financial and telephonic records on the other.
According to today’s majority opinion, the Government can acquire a
record of every credit card purchase and phone call a person makes
over months or years without upsetting a legitimate expectation of
privacy. But, in the Court’s view, the Government crosses a
constitutional line when it obtains a court’s approval to issue a
subpoena for more than six days of cell-site records in order to
determine whether a person was within several hundred city blocks
of a crime scene. That distinction is illogical and will frustrate
principled application of the Fourth Amendment in many routine yet
vital law enforcement operations.

															It is true that the Cyber Age has vast potential
both to expand and restrict individual freedoms in dimensions not
contemplated in earlier times. See Packingham v. North
Carolina , 582 U. S. ___, ___–___ (2017) (slip op., at
4–6). For the reasons that follow, however, there is simply no
basis here for concluding that the Government interfered with
information that the cell phone customer, either from a legal or
commonsense standpoint, should have thought the law would deem
owned or controlled by him.

															I

															Before evaluating the question presented it is
helpful to understand the nature of cell-site records, how they are
commonly used by cell phone service providers, and their proper use
by law enforcement.

															When a cell phone user makes a call, sends a
text message or e-mail, or gains access to the Internet, the cell
phone establishes a radio connection to an antenna at a nearby cell
site. The typical cell site covers a more-or-less circular
geographic area around the site. It has three (or sometimes six)
separate antennas pointing in different directions. Each provides
cell service for a different 120-degree (or 60-degree) sector of
the cell site’s circular coverage area. So a cell phone activated
on the north side of a cell site will connect to a different
antenna than a cell phone on the south side.

															Cell phone service providers create records each
time a cell phone connects to an antenna at a cell site. For a
phone call, for example, the provider records the date, time, and
duration of the call; the phone numbers making and receiving the
call; and, most relevant here, the cell site used to make the call,
as well as the specific antenna that made the connection. The
cell-site and antenna data points, together with the date and time
of connection, are known as cell-site location information, or
cell-site records. By linking an individual’s cell phone to a
particular 120- or 60-degree sector of a cell site’s coverage area
at a particular time, cell-site records reveal the general location
of the cell phone user.

															The location information revealed by cell-site
records is imprecise, because an individual cell-site sector
usually covers a large geographic area. The FBI agent who offered
expert testimony about the cell-site records at issue here
testified that a cell site in a city reaches between a half mile
and two miles in all directions. That means a 60-degree sector
covers between approximately one-eighth and two square miles (and a
120-degree sector twice that area). To put that in perspective, in
urban areas cell-site records often would reveal the location of a
cell phone user within an area covering between around a dozen and
several hundred city blocks. In rural areas cell-site records can
be up to 40 times more imprecise. By contrast, a Global Positioning
System (GPS) can reveal an individ- ual’s location within around 15
feet.

															Major cell phone service providers keep
cell-site records for long periods of time. There is no law
requiring them to do so. Instead, providers contract with their
customers to collect and keep these records because they are
valuable to the providers. Among other things, providers aggregate
the records and sell them to third parties along with other
information gleaned from cell phone usage. This data can be used,
for example, to help a department store determine which of various
prospective store locations is likely to get more foot traffic from
middle-aged women who live in affluent zip codes. The market for
cell phone data is now estimated to be in the billions of dollars.
See Brief for Technology Experts as Amici Curiae 23.

															Cell-site records also can serve an important
investigative function, as the facts of this case demonstrate.
Petitioner, Timothy Carpenter, along with a rotating group of
accomplices, robbed at least six RadioShack and T-Mobile stores at
gunpoint over a 2-year period. Five of those robberies occurred in
the Detroit area, each crime at least four miles from the last. The
sixth took place in Warren, Ohio, over 200 miles from Detroit.

															The Government, of course, did not know all of
these details in 2011 when it began investigating Carpenter. In
April of that year police arrested four of Carpenter’s
co-conspirators. One of them confessed to committing nine robberies
in Michigan and Ohio between December 2010 and March 2011. He
identified 15 accomplices who had participated in at least one of
those robberies; named Carpenter as one of the accomplices; and
provided Carpenter’s cell phone number to the authorities. The
suspect also warned that the other members of the conspiracy
planned to commit more armed robberies in the immediate future.

															The Government at this point faced a daunting
task. Even if it could identify and apprehend the suspects, still
it had to link each suspect in this changing criminal gang to
specific robberies in order to bring charges and convict. And, of
course, it was urgent that the Government take all necessary steps
to stop the ongoing and dangerous crime spree.

															Cell-site records were uniquely suited to this
task. The geographic dispersion of the robberies meant that, if
Carpenter’s cell phone were within even a dozen to several hundred
city blocks of one or more of the stores when the different
robberies occurred, there would be powerful circumstantial evidence
of his participation; and this would be especially so if his cell
phone usually was not located in the sectors near the stores except
during the robbery times.

															To obtain these records, the Government applied
to federal magistrate judges for disclosure orders pursuant to
§2703(d) of the Stored Communications Act. That Act authorizes a
magistrate judge to issue an order requiring disclosure of
cell-site records if the Government demonstrates “specific and
articulable facts showing that there are reasonable grounds to
believe” the records “are relevant and material to an ongoing
criminal investigation.” 18 U. S. C. §§2703(d), 2711(3).
The full statutory provision is set out in the Appendix, infra .

															From Carpenter’s primary service provider,
MetroPCS, the Government obtained records from between December
2010 and April 2011, based on its understanding that nine robberies
had occurred in that timeframe. The Government also requested seven
days of cell-site records from Sprint, spanning the time around the
robbery in Warren, Ohio. It obtained two days of records.

															These records confirmed that Carpenter’s cell
phone was in the general vicinity of four of the nine robberies,
including the one in Ohio, at the times those robberies
occurred.

															II

															The first Clause of the Fourth Amendment
provides that “the right of the people to be secure in their
persons, houses, papers, and effects, against unreasonable searches
and seizures, shall not be violated.” The customary beginning point
in any Fourth Amendment search case is whether the Government’s
actions constitute a “search” of the defendant’s person, house,
papers, or effects, within the meaning of the constitutional
provision. If so, the next question is whether that search was
reasonable.

															Here the only question necessary to decide is
whether the Government searched anything of Carpenter’s when it
used compulsory process to obtain cell-site records from
Carpenter’s cell phone service providers. This Court’s decisions in Miller and Smith dictate that the answer is no, as
every Court of Appeals to have considered the question has
recognized. See United States v. Thompson , 866
F. 3d 1149 (CA10 2017); United States v. Graham ,
824 F. 3d 421 (CA4 2016) (en banc); Carpenter v. United States , 819 F. 3d 880 (CA6 2016); United
States v. Davis , 785 F. 3d 498 (CA11 2015) (en
banc); In re Application of U. S. for Historical Cell
Site Data , 724 F. 3d 600 (CA5 2013).

															A Miller and Smith hold that
individuals lack any protected Fourth Amendment interests in
records that are possessed, owned, and controlled only by a third
party. In Miller federal law enforcement officers obtained
four months of the defendant’s banking records. 425 U. S., at
437–438. And in Smith state police obtained records of the
phone numbers dialed from the defendant’s home phone. 442
U. S., at 737. The Court held in both cases that the officers
did not search anything belonging to the defendants within the
meaning of the Fourth Amendment. The defendants could “assert
neither ownership nor possession” of the records because the
records were created, owned, and controlled by the companies. Miller , supra , at 440; see Smith , supra , at 741. And the defendants had no reasonable
expectation of privacy in information they “voluntarily conveyed to
the [companies] and exposed to their employees in the ordinary
course of business.” Miller , supra , at 442; see Smith , 442 U. S., at 744. Rather, the defendants
“assumed the risk that the information would be divulged to
police.” Id. , at 745. Miller and Smith have been
criticized as being based on too narrow a view of reasonable
expectations of privacy. See, e.g., Ashdown, The Fourth
Amendment and the “Legitimate Expectation of Privacy,” 34 Vand.
L. Rev. 1289, 1313–1316 (1981). Those criticisms, however, are
unwarranted. The principle established in Miller and Smith is correct for two reasons, the first relating to a
defendant’s attenuated interest in property owned by another, and
the second relating to the safeguards inherent in the use of
compulsory process.

															First, Miller and Smith placed
necessary limits on the ability of individuals to assert Fourth
Amendment interests in property to which they lack a “requisite
connection.” Minnesota v. Carter , 525 U. S. 83,
99 (1998) (Kennedy, J., concurring). Fourth Amendment rights, after
all, are personal. The Amendment protects “[t]he right of the
people to be secure in their . . . persons,
houses, papers, and effects”—not the persons, houses, papers, and
effects of others. (Emphasis added.)

															The concept of reasonable expectations of
privacy, first announced in Katz v. United States ,
389 U. S. 347 (1967), sought to look beyond the “arcane
distinctions developed in property and tort law” in evaluating
whether a person has a sufficient connection to the thing or place
searched to assert Fourth Amendment interests in it. Rakas v. Illinois , 439 U. S. 128, 143 (1978). Yet “property
concepts” are, nonetheless, fundamental “in determining the
presence or absence of the privacy interests protected by that
Amendment.” Id., at 143–144, n. 12. This is so for at
least two reasons. First, as a matter of settled expectations from
the law of property, individuals often have greater expectations of
privacy in things and places that belong to them, not to others.
And second, the Fourth Amendment’s protections must remain tethered
to the text of that Amendment, which, again, protects only a
person’s own “persons, houses, papers, and effects.” Katz did not abandon reliance on
property-based concepts. The Court in Katz analogized the
phone booth used in that case to a friend’s apartment, a taxicab,
and a hotel room. 389 U. S., at 352, 359. So when the
defendant “shu[t] the door behind him” and “pa[id] the toll,” id., at 352, he had a temporary interest in the space and a
legitimate expectation that others would not intrude, much like the
interest a hotel guest has in a hotel room, Stoner v. California , 376 U. S. 483 (1964), or an overnight guest
has in a host’s home, Minnesota v. Olson , 495
U. S. 91 (1990). The Government intruded on that space when it
attached a listening device to the phone booth. Katz , 389
U. S., at 348. (And even so, the Court made it clear that the
Government’s search could have been reasonable had there been
judicial approval on a case-specific basis, which, of course, did
occur here. Id ., at 357–359.) Miller and Smith set forth an
important and necessary limitation on the Katz framework.
They rest upon the commonsense principle that the absence of
property law analogues can be dispositive of privacy expectations.
The defendants in those cases could expect that the third-party
businesses could use the records the companies collected, stored,
and classified as their own for any number of business and
commercial purposes. The businesses were not bailees or custodians
of the records, with a duty to hold the records for the defendants’
use. The defendants could make no argument that the records were
their own papers or effects. See Miller , supra , at
440 (“the documents subpoenaed here are not respondent’s ‘private
papers’ ”); Smith , supra , at 741 (“petitioner
obviously cannot claim that his ‘property’ was invaded”). The
records were the business entities’ records, plain and simple. The
defendants had no reason to believe the records were owned or
controlled by them and so could not assert a reasonable expectation
of privacy in the records.

															The second principle supporting Miller and Smith is the longstanding rule that the Government may
use compulsory process to compel persons to disclose documents and
other evidence within their possession and control. See United
States v. Nixon , 418 U. S. 683, 709 (1974) (it is
an “ancient proposition of law” that “the public has a right to
every man’s evidence” (internal quotation marks and alterations
omitted)). A subpoena is different from a warrant in its force and
intrusive power. While a warrant allows the Government to enter and
seize and make the examination itself, a subpoena simply requires
the person to whom it is directed to make the disclosure. A
subpoena, moreover, provides the recipient the “opportunity to
present objections” before complying, which further mitigates the
intrusion. Oklahoma Press Publishing Co. v. Walling ,
327 U. S. 186, 195 (1946).

															For those reasons this Court has held that a
subpoena for records, although a “constructive” search subject to
Fourth Amendment constraints, need not comply with the procedures
applicable to warrants—even when challenged by the person to whom
the records belong. Id., at 202, 208. Rather, a subpoena
complies with the Fourth Amendment’s reasonableness requirement so
long as it is “ ‘sufficiently limited in scope, relevant in
purpose, and specific in directive so that compliance will not be
unreasonably burdensome.’ ” Donovan v. Lone Steer,
Inc. , 464 U. S. 408, 415 (1984). Persons with no
meaningful interests in the records sought by a subpoena, like the
defendants in Miller and Smith , have no rights to
object to the records’ disclosure—much less to assert that the
Government must obtain a warrant to compel disclosure of the
records. See Miller , 425 U. S., at 444–446; SEC v. Jerry T. O’Brien, Inc. , 467 U. S. 735, 742–743
(1984).

															Based on Miller and Smith and the
principles underlying those cases, it is well established that
subpoenas may be used to obtain a wide variety of records held by
businesses, even when the records contain private information. See
2 W. LaFave, Search and Seizure §4.13 (5th ed. 2012). Credit cards
are a prime example. State and federal law enforcement, for
instance, often subpoena credit card statements to develop probable
cause to prosecute crimes ranging from drug trafficking and
distribution to healthcare fraud to tax evasion. See United
States v. Phibbs , 999 F. 2d 1053 (CA6 1993) (drug
distribution); McCune v. DOJ , 592 Fed. Appx. 287 (CA5
2014) (healthcare fraud); United States v. Green , 305
F. 3d 422 (CA6 2002) (drug trafficking and tax evasion); see
also 12 U. S. C. §§3402(4), 3407 (allowing the Government
to subpoena financial records if “there is reason to believe that
the records sought are relevant to a legitimate law enforcement
inquiry”). Subpoenas also may be used to obtain vehicle
registration records, hotel records, employment records, and
records of utility usage, to name just a few other examples. See 1
LaFave, supra , §2.7(c).

															And law enforcement officers are not alone in
their reliance on subpoenas to obtain business records for
legitimate investigations. Subpoenas also are used for
investigatory purposes by state and federal grand juries, see United States v. Dionisio , 410 U. S. 1 (1973),
state and federal administrative agencies, see Oklahoma
Press , supra , and state and federal legislative bodies,
see McPhaul v. United States , 364 U. S. 372
(1960).

															B

															Carpenter does not question these traditional
investigative practices. And he does not ask the Court to
reconsider Miller and Smith . Carpenter argues only
that, under Miller and Smith , the Government may not
use compulsory process to acquire cell-site records from cell phone
service providers.

															There is no merit in this argument. Cell-site
records, like all the examples just discussed, are created, kept,
classified, owned, and controlled by cell phone service providers,
which aggregate and sell this information to third parties. As in Miller , Carpenter can “assert neither ownership nor
possession” of the records and has no control over them. 425
U. S., at 440.

															Carpenter argues that he has Fourth Amendment
interests in the cell-site records because they are in essence his
personal papers by operation of 47 U. S. C. §222. That
statute imposes certain restrictions on how providers may use
“customer proprietary network information”—a term that encompasses
cell-site records. §§222(c), (h)(1)(A). The statute in general
prohibits providers from disclosing personally identifiable
cell-site records to private third parties. §222(c)(1). And it
allows customers to request cell-site records from the provider.
§222(c)(2).

															Carpenter’s argument is unpersuasive, however,
for §222 does not grant cell phone customers any meaningful
interest in cell-site records. The statute’s confidentiality
protections may be overridden by the interests of the providers or
the Government. The providers may disclose the records “to protect
the[ir] rights or property” or to “initiate, render, bill, and
collect for telecommunications services.” §§222(d)(1), (2). They
also may disclose the records “as required by law”—which, of
course, is how they were disclosed in this case. §222(c)(1). Nor
does the statute provide customers any practical control over the
records. Customers do not create the records; they have no say in
whether or for how long the records are stored; and they cannot
require the records to be modified or destroyed. Even their right
to request access to the records is limited, for the statute “does
not preclude a carrier from being reimbursed by the customers
. . . for the costs associated with making such
disclosures.” H. R. Rep. No. 104–204, pt. 1, p. 90 (1995). So
in every legal and practical sense the “network information”
regulated by §222 is, under that statute, “proprietary” to the
service providers, not Carpenter. The Court does not argue
otherwise.

															Because Carpenter lacks a requisite connection
to the cell-site records, he also may not claim a reasonable
expectation of privacy in them. He could expect that a third
party—the cell phone service provider—could use the information it
collected, stored, and classified as its own for a variety of
business and commercial purposes.

															All this is not to say that Miller and Smith are without limits. Miller and Smith may
not apply when the Government obtains the modern-day equivalents of
an individual’s own “papers” or “effects,” even when those papers
or effects are held by a third party. See Ex parte Jackson ,
96 U. S. 727, 733 (1878) (letters held by mail carrier); United States v. Warshak , 631 F. 3d 266, 283–288
(CA6 2010) (e-mails held by Internet service provider). As already
discussed, however, this case does not involve property or a
bailment of that sort. Here the Government’s acquisition of
cell-site records falls within the heartland of Miller and Smith .

															In fact, Carpenter’s Fourth Amendment objection
is even weaker than those of the defendants in Miller and Smith . Here the Government did not use a mere sub- poena to
obtain the cell-site records. It acquired the records only after it
proved to a Magistrate Judge reasonable grounds to believe that the
records were relevant and material to an ongoing criminal
investigation. See 18 U. S. C. §2703(d). So even if §222
gave Carpenter some attenuated interest in the records, the
Government’s conduct here would be reasonable under the standards
governing subpoenas. See Donovan , 464 U. S., at
415.

															Under Miller and Smith , then, a
search of the sort that requires a warrant simply did not occur
when the Government used court-approved compulsory process, based
on a finding of reasonable necessity, to compel a cell phone
service provider, as owner, to disclose cell-site records.

															III

															The Court rejects a straightforward
application of Miller and Smith . It concludes instead
that applying those cases to cell-site records would work a
“significant extension” of the principles underlying them, ante, at 15, and holds that the acquisition of more than six
days of cell-site records constitutes a search, ante, at 11,
n. 3.

															In my respectful view the majority opinion
misreads this Court’s precedents, old and recent, and transforms Miller and Smith into an unprincipled and unworkable
doctrine. The Court’s newly conceived constitutional standard will
cause confusion; will undermine traditional and important law
enforcement practices; and will allow the cell phone to become a
protected medium that dangerous persons will use to commit serious
crimes.

															A

															The Court errs at the outset by attempting to
sidestep Miller and Smith . The Court frames this case
as following instead from United States v. Knotts ,
460 U. S. 276 (1983), and United States v. Jones , 565 U. S. 400 (2012). Those cases, the Court
suggests, establish that “individuals have a reasonable expectation
of privacy in the whole of their physical movements.” Ante ,
at 7–9, 12. Knotts held just the opposite: “A person
traveling in an automobile on public thoroughfares has no
reasonable expectation of privacy in his movements from one place
to another.” 460 U. S., at 281. True, the Court in Knotts also suggested that “different constitutional
principles may be applicable” to “dragnet-type law enforcement
practices.” Id., at 284. But by dragnet practices the Court
was referring to “ ‘twenty-four hour surveillance of any
citizen of this country . . . without judicial knowledge
or supervision.’ ” Id., at 283.

															Those “different constitutional principles”
mentioned in Knotts , whatever they may be, do not apply in
this case. Here the Stored Communications Act requires a neutral
judicial officer to confirm in each case that the Government has
“reasonable grounds to believe” the cell-site records “are relevant
and material to an ongoing criminal investigation.” 18
U. S. C. §2703(d). This judicial check mitigates the
Court’s concerns about “ ‘a too permeating police
surveillance.’ ” Ante , at 6 (quoting United
States v. Di Re , 332 U. S. 581, 595 (1948)). Here,
even more so than in Knotts , “reality hardly suggests
abuse.” 460 U. S., at 284.

															The Court’s reliance on Jones fares no
better. In Jones the Government installed a GPS tracking
device on the defendant’s automobile. The Court held the Government
searched the automobile because it “physically occupied private
property [of the defendant] for the purpose of obtaining
information.” 565 U. S., at 404. So in Jones it was
“not necessary to inquire about the target’s expectation of privacy
in his vehicle’s movements.” Grady v. North Carolina ,
575 U. S. ___, ___ (2015) ( per curiam ) (slip op., at
3).

															Despite that clear delineation of the Court’s
holding in Jones , the Court today declares that Jones applied the “ ‘different constitutional principles’ ”
alluded to in Knotts to establish that an individual has an
expectation of pri- vacy in the sum of his whereabouts. Ante , at 8, 12. For that proposition the majority relies on
the two concurring opinions in Jones , one of which stated
that “longer term GPS monitoring in investigations of most offenses
impinges on expectations of privacy.” 565 U. S., at 430
(Alito, J., concurring). But Jones involved direct
governmental surveillance of a defendant’s automobile without
judicial authorization—specifically, GPS surveillance accurate
within 50 to 100 feet. Id. , at 402–403. Even assuming that
the different constitutional principles mentioned in Knotts would apply in a case like Jones —a proposition the Court was
careful not to announce in Jones , supra , at
412–413—those principles are inapplicable here. Cases like this
one, where the Government uses court-approved compulsory process to
obtain records owned and controlled by a third party, are governed
by the two majority opinions in Miller and Smith .

															B

															The Court continues its analysis by
misinterpreting Miller and Smith , and then it reaches
the wrong outcome on these facts even under its flawed
standard.

															The Court appears, in my respectful view, to
read Miller and Smith to establish a balancing test.
For each “qualitatively different category” of information, the
Court suggests, the privacy interests at stake must be weighed
against the fact that the information has been disclosed to a third
party. See ante , at 11, 15–17. When the privacy interests
are weighty enough to “overcome” the third-party disclosure, the
Fourth Amendment’s protections apply. See ante , at 17.

															That is an untenable reading of Miller and Smith . As already discussed, the fact that information
was relinquished to a third party was the entire basis for
concluding that the defendants in those cases lacked a reasonable
expectation of privacy. Miller and Smith do not
establish the kind of category-by-category balancing the Court
today prescribes.

															But suppose the Court were correct to say that Miller and Smith rest on so imprecise a foundation.
Still the Court errs, in my submission, when it concludes that
cell-site records implicate greater privacy interests—and thus
deserve greater Fourth Amendment protection—than financial records
and telephone records.

															Indeed, the opposite is true. A person’s
movements are not particularly private. As the Court recognized in Knotts , when the defendant there “traveled over the public
streets he voluntarily conveyed to anyone who wanted to look the
fact that he was traveling over particular roads in a particular
direction, the fact of whatever stops he made, and the fact of his
final destination.” 460 U. S., at 281–282. Today expectations
of privacy in one’s location are, if anything, even less reasonable
than when the Court decided Knotts over 30 years ago.
Millions of Americans choose to share their location on a daily
basis, whether by using a variety of location-based services on
their phones, or by sharing their location with friends and the
public at large via social media.

															And cell-site records, as already discussed,
disclose a person’s location only in a general area. The records at
issue here, for example, revealed Carpenter’s location within an
area covering between around a dozen and several hundred city
blocks. “Areas of this scale might encompass bridal stores and Bass
Pro Shops, gay bars and straight ones, a Methodist church and the
local mosque.” 819 F. 3d 880, 889 (CA6 2016). These records
could not reveal where Carpenter lives and works, much less his
“ ‘familial, political, professional, religious, and sexual
associations.’ ” Ante , at 12 (quoting Jones , supra , at 415 (Sotomayor, J., concurring)).

															By contrast, financial records and telephone
records do “ ‘revea[l] . . . personal affairs,
opinions, habits and associations.’ ” Miller , 425
U. S., at 451 (Brennan, J., dissenting); see Smith , 442
U. S., at 751 (Marshall, J., dissenting). What persons
purchase and to whom they talk might disclose how much money they
make; the political and religious organizations to which they
donate; whether they have visited a psychiatrist, plastic surgeon,
abortion clinic, or AIDS treatment center; whether they go to gay
bars or straight ones; and who are their closest friends and family
members. The troves of intimate information the Government can and
does obtain using financial records and telephone records dwarfs
what can be gathered from cell-site records.

															Still, the Court maintains, cell-site records
are “unique” because they are “comprehensive” in their reach; allow
for retrospective collection; are “easy, cheap, and efficient
compared to traditional investigative tools”; and are not exposed
to cell phone service providers in a meaningfully voluntary manner. Ante , at 11–13, 17, 22. But many other kinds of business
records can be so described. Financial records are of vast scope.
Banks and credit card companies keep a comprehensive account of
almost every transaction an individual makes on a daily basis.
“With just the click of a button, the Government can access each
[company’s] deep repository of historical [financial] information
at practically no expense.” Ante , at 12–13. And the decision
whether to transact with banks and credit card companies is no more
or less voluntary than the decision whether to use a cell phone.
Today, just as when Miller was decided, “ ‘it is
impossible to participate in the economic life of contemporary
society without maintaining a bank account.’ ” 425 U. S.,
at 451 (Brennan, J., dissenting). But this Court, nevertheless, has
held that individ- uals do not have a reasonable expectation of
privacy in financial records.

															Perhaps recognizing the difficulty of drawing
the constitutional line between cell-site records and financial and
telephonic records, the Court posits that the accuracy of cell-site
records “is rapidly approaching GPS-level precision.” Ante ,
at 14. That is certainly plausible in the era of cyber technology,
yet the privacy interests associated with location information,
which is often disclosed to the public at large, still would not
outweigh the privacy interests implicated by financial and
telephonic records.

															Perhaps more important, those future
developments are no basis upon which to resolve this case. In
general, the Court “risks error by elaborating too fully on the
Fourth Amendment implications of emerging technology before its
role in society has become clear.” Ontario v. Quon ,
560 U. S. 746, 759 (2010). That judicial caution, prudent in
most cases, is imperative in this one.

															Technological changes involving cell phones have
complex effects on crime and law enforcement. Cell phones make
crimes easier to coordinate and conceal, while also providing the
Government with new investigative tools that may have the potential
to upset traditional privacy expectations. See Kerr, An
Equilibrium-Adjustment Theory of the Fourth Amendment, 125 Harv.
L. Rev 476, 512–517 (2011). How those competing effects
balance against each other, and how property norms and expectations
of privacy form around new technology, often will be difficult to
determine during periods of rapid technological change. In those
instances, and where the governing legal standard is one of
reasonableness, it is wise to defer to legislative judgments like
the one embodied in §2703(d) of the Stored Communications Act. See Jones , 565 U. S., at 430 (Alito, J., concurring). In
§2703(d) Congress weighed the privacy interests at stake and
imposed a judicial check to prevent executive overreach. The Court
should be wary of upsetting that legislative balance and erecting
constitutional barriers that foreclose further legislative
instructions. See Quon , supra , at 759. The last thing
the Court should do is incorporate an arbitrary and outside
limit—in this case six days’ worth of cell-site records—and use it
as the foundation for a new constitutional framework. The Court’s
decision runs roughshod over the mechanism Congress put in place to
govern the acquisition of cell-site records and closes off further
legislative debate on these issues.

															C

															The Court says its decision is a “narrow one.” Ante, at 17. But its reinterpretation of Miller and Smith will have dramatic consequences for law enforcement,
courts, and society as a whole.

															Most immediately, the Court’s holding that the
Government must get a warrant to obtain more than six days of
cell-site records limits the effectiveness of an important
investigative tool for solving serious crimes. As this case
demonstrates, cell-site records are uniquely suited to help the
Government develop probable cause to apprehend some of the Nation’s
most dangerous criminals: serial killers, rapists, arsonists,
robbers, and so forth. See also, e.g. , Davis , 785
F. 3d, at 500–501 (armed robbers); Brief for Alabama
et al. as Amici Curiae 21–22 (serial killer). These
records often are indispensable at the initial stages of
investigations when the Government lacks the evidence necessary to
obtain a warrant. See United States v. Pembrook , 876
F.3d 812, 816–819 (CA6 2017). And the long-term nature of many
serious crimes, including serial crimes and terrorism offenses, can
necessitate the use of significantly more than six days of
cell-site records. The Court’s arbitrary 6-day cutoff has the
perverse effect of nullifying Congress’ reasonable framework for
obtain- ing cell-site records in some of the most serious criminal
investigations.

															The Court’s decision also will have
ramifications that extend beyond cell-site records to other kinds
of information held by third parties, yet the Court fails “to
provide clear guidance to law enforcement” and courts on key issues
raised by its reinterpretation of Miller and Smith . Riley v. California , 573 U. S. ___, ___ (2014)
(slip op., at 22). First , the Court’s holding is premised on
cell-site records being a “distinct category of information” from
other business records. Ante , at 15. But the Court does not
explain what makes something a distinct category of information.
Whether credit card records are distinct from bank records; whether
payment records from digital wallet applications are distinct from
either; whether the electronic bank records available today are
distinct from the paper and microfilm records at issue in Miller ; or whether cell-phone call records are distinct from
the home-phone call records at issue in Smith , are just a
few of the difficult questions that require answers under the
Court’s novel conception of Miller and Smith . Second , the majority opinion gives courts
and law enforcement officers no indication how to determine whether
any particular category of information falls on the
financial-records side or the cell-site-records side of its newly
conceived constitutional line. The Court’s multifactor
analysis—considering intimacy, comprehensiveness, expense,
retrospectivity, and voluntariness—puts the law on a new and
unstable foundation. Third , even if a distinct category of
information is deemed to be more like cell-site records than
financial records, courts and law enforcement officers will have to
guess how much of that information can be requested before a
warrant is required. The Court suggests that less than seven days
of location information may not require a warrant. See ante, at 11, n. 3; see also ante, at 17–18 (expressing no
opinion on “real-time CSLI,” tower dumps, and security-camera
footage). But the Court does not explain why that is so, and
nothing in its opinion even alludes to the considerations that
should determine whether greater or lesser thresholds should apply
to information like IP addresses or website browsing history. Fourth , by invalidating the Government’s
use of court-approved compulsory process in this case, the Court
calls into question the subpoena practices of federal and state
grand juries, legislatures, and other investigative bodies, as
Justice Alito’s opinion explains. See post, at 2–19
(dissenting opinion). Yet the Court fails even to mention the
serious consequences this will have for the proper administration
of justice.

															In short, the Court’s new and uncharted course
will inhibit law enforcement and “keep defendants and judges
guessing for years to come.” Riley , 573 U. S., at ___
(slip op., at 25) (internal quotation marks omitted).

															*  *  *

															This case should be resolved by interpreting
accepted property principles as the baseline for reasonable
expectations of privacy. Here the Government did not search
anything over which Carpenter could assert ownership or control.
Instead, it issued a court-authorized subpoena to a third party to
disclose information it alone owned and controlled. That should
suffice to resolve this case.

															Having concluded, however, that the Government
searched Carpenter when it obtained cell-site records from his cell
phone service providers, the proper resolution of this case should
have been to remand for the Court of Appeals to determine in the
first instance whether the search was reasonable. Most courts of
appeals, believing themselves bound by Miller and Smith , have not grappled with this question. And the Court’s
reflexive imposition of the warrant requirement obscures important
and difficult issues, such as the scope of Congress’ power to
authorize the Government to collect new forms of information using
processes that deviate from traditional warrant procedures, and how
the Fourth Amendment’s reasonableness requirement should apply when
the Government uses compulsory process instead of engaging in an
actual, physical search.

															These reasons all lead to this respectful
dissent.

															APPENDIX

															“ §2703. Required disclosure of customer
communications or records “(d) Requirements for Court Order.—A court order
for disclosure under subsection (b) or (c) may be issued by any
court that is a court of competent jurisdiction and shall issue
only if the governmental entity offers specific and articulable
facts showing that there are reasonable grounds to believe that the
contents of a wire or electronic communication, or the records or
other information sought, are relevant and material to an ongoing
criminal investigation. In the case of a State governmental
authority, such a court order shall not issue if prohibited by the
law of such State. A court issuing an order pursuant to this
section, on a motion made promptly by the service provider, may
quash or modify such order, if the information or records requested
are unusually voluminous in nature or compliance with such order
otherwise would cause an undue burden on such provider.” SUPREME COURT OF THE UNITED STATES

															_________________

															No. 16–402

															_________________

															TIMOTHY IVORY CARPENTER, PETITIONER v. UNITED STATES

															on writ of certiorari to the united states
court of appeals for the sixth circuit

															[June 22, 2018]

															Justice Thomas, dissenting.

															This case should not turn on “whether” a search
occurred. Ante, at 1. It should turn, instead, on whose property was searched. The Fourth Amendment guarantees
individuals the right to be secure from unreasonable searches of
“ their persons, houses, papers, and effects.” (Emphasis
added.) In other words, “ each person has the right to be
secure against unreasonable searches . . . in his
own person, house, papers, and effects.” Minnesota v. Carter , 525 U. S. 83, 92 (1998) (Scalia, J.,
concurring). By obtaining the cell-site records of MetroPCS and
Sprint, the Government did not search Carpenter’s property. He did
not create the records, he does not maintain them, he cannot
control them, and he cannot destroy them. Neither the terms of his
contracts nor any provision of law makes the records his. The
records belong to MetroPCS and Sprint.

															The Court concludes that, although the records
are not Carpenter’s, the Government must get a warrant because
Carpenter had a reasonable “expectation of privacy” in the location
information that they reveal. Ante, at 11. I agree with
Justice Kennedy, Justice Alito, Justice Gorsuch, and every Court of
Appeals to consider the question that this is not the best reading
of our precedents.

															The more fundamental problem with the Court’s
opinion, however, is its use of the “reasonable expectation of
privacy” test, which was first articulated by Justice Harlan in Katz v. United States , 389 U. S. 347, 360–361
(1967) (concurring opinion). The Katz test has no basis in
the text or history of the Fourth Amendment. And, it invites courts
to make judgments about policy, not law. Until we confront the
problems with this test, Katz will continue to distort
Fourth Amendment jurisprudence. I respectfully dissent.

															I Katz was the culmination of a series of
decisions applying the Fourth Amendment to electronic
eavesdropping. The first such decision was Olmstead v. United States , 277 U. S. 438 (1928), where federal
officers had intercepted the defendants’ conversations by tapping
telephone lines near their homes. Id., at 456–457. In an
opinion by Chief Justice Taft, the Court concluded that this
wiretap did not violate the Fourth Amendment. No “search” occurred,
according to the Court, because the officers did not physically
enter the defendants’ homes. Id., at 464–466. And neither
the telephone lines nor the defendants’ intangible conversations
qualified as “persons, houses, papers, [or] effects” within the
meaning of the Fourth Amendment. Ibid. [ 1 ] In the ensuing decades, this Court adhered
to Olmstead and rejected Fourth Amendment
challenges to various methods of electronic surveillance. See On
Lee v. United States , 343 U. S. 747, 749–753 (1952)
(use of microphone to overhear conversations with confidential
informant); Goldman v. United States , 316 U. S.
129, 131–132, 135–136 (1942) (use of detectaphone to hear
conversations in office next door).

															In the 1960’s, however, the Court began to
retreat from Olmstead . In Silverman v. United
States , 365 U. S. 505 (1961), for example, federal
officers had eavesdropped on the defendants by driving a “spike
mike” several inches into the house they were occupying. Id., at 506–507. This was a “search,” the Court held,
because the “unauthorized physical penetration into the premises”
was an “actual intrusion into a constitutionally protected area.” Id., at 509, 512. The Court did not mention Olmstead ’s other holding that intangible conversations are
not “persons, houses, papers, [or] effects.” That omission was
significant. The Court confirmed two years later that “[i]t follows
from [ Silverman ] that the Fourth Amendment may protect
against the overhearing of verbal statements as well as against the
more traditional seizure of ‘papers and effects.’ ” Wong
Sun v. United States , 371 U. S. 471, 485 (1963);
accord, Berger v. New York , 388 U. S. 41, 51
(1967).

															In Katz , the Court rejected Olmstead ’s remaining holding—that eavesdropping is not a
search absent a physical intrusion into a constitutionally
protected area. The federal officers in Katz had intercepted
the defendant’s conversations by attaching an electronic device to
the outside of a public telephone booth. 389 U. S., at 348.
The Court concluded that this was a “search” because the officers
“violated the privacy upon which [the defendant] justifiably relied
while using the telephone booth.” Id., at 353. Although the
device did not physically penetrate the booth, the Court overruled Olmstead and held that “the reach of [the Fourth] Amendment
cannot turn upon the presence or absence of a physical intrusion.”
389 U. S., at 353. The Court did not explain what should
replace Olmstead ’s physical-intrusion requirement. It simply
asserted that “the Fourth Amendment protects people, not places”
and “what [a person] seeks to preserve as private . . .
may be constitutionally protected.” 389 U. S., at 351.

															Justice Harlan’s concurrence in Katz attempted to articulate the standard that was missing from the
majority opinion. While Justice Harlan agreed that “ ‘the
Fourth Amendment protects people, not places,’ ” he stressed
that “[t]he question . . . is what protection it affords
to those people,” and “the answer . . . requires
reference to a ‘place.’ ” Id., at 361. Justice Harlan
identified a “twofold requirement” to determine when the
protections of the Fourth Amendment apply: “first that a person
have exhibited an actual (subjective) expectation of privacy and,
second, that the expectation be one that society is prepared to
recognize as ‘reasonable.’ ” Ibid. Justice Harlan did not cite anything for this
“expectation of privacy” test, and the parties did not discuss it
in their briefs. The test appears to have been presented for the
first time at oral argument by one of the defendant’s lawyers. See
Winn, Katz and the Origins of the “Reason- able Expectation
of Privacy” Test, 40 McGeorge L. Rev. 1, 9–10 (2009). The
lawyer, a recent law-school graduate, apparently had an
“[e]piphany” while preparing for oral argument. Schneider, Katz
v. United States : The Untold Story, 40 McGeorge L. Rev.
13, 18 (2009). He conjectured that, like the “reasonable person”
test from his Torts class, the Fourth Amendment should turn on
“whether a reasonable person . . . could have expected
his communication to be private.” Id., at 19. The lawyer
presented his new theory to the Court at oral argument. See, e.g., Tr. of Oral Arg. in Katz v. United
States , O. T. 1967, No. 35, p. 5 (proposing a
test of “whether or not, objectively speaking, the communication
was intended to be private”); id., at 11 (“We propose a test
using a way that’s not too dissimilar from the tort ‘reasonable
man’ test”). After some questioning from the Justices, the lawyer
conceded that his test should also require individuals to
subjectively expect privacy. See id., at 12. With that
modification, Justice Harlan seemed to accept the lawyer’s test
almost verbatim in his concurrence.

															Although the majority opinion in Katz had
little practical significance after Congress enacted the Omnibus
Crime Control and Safe Streets Act of 1968, Justice Harlan’s
concurrence profoundly changed our Fourth Amendment jurisprudence.
It took only one year for the full Court to adopt his two-pronged
test. See Terry v. Ohio , 392 U. S. 1, 10 (1968).
And by 1979, the Court was describing Justice Harlan’s test as the
“lodestar” for determining whether a “search” had occurred. Smith v. Maryland , 442 U. S. 735, 739 (1979).
Over time, the Court minimized the subjective prong of Justice
Harlan’s test. See Kerr, Katz Has Only One Step: The
Irrelevance of Subjective Expectations, 82 U. Chi.
L. Rev. 113 (2015). That left the objective prong—the
“reasonable expectation of privacy” test that the Court still
applies today. See ante, at 5; United States v. Jones , 565 U. S. 400, 406 (2012).

															II

															Under the Katz test, a “search” occurs
whenever “government officers violate a person’s ‘reasonable
expectation of privacy.’ ” Jones , supra, at 406.
The most glaring problem with this test is that it has “no
plausible foundation in the text of the Fourth Amendment.” Carter , 525 U. S., at 97 (opinion of Scalia, J.). The
Fourth Amendment, as relevant here, protects “[t]he right of the
people to be secure in their persons, houses, papers, and effects,
against unreasonable searches.” By defining “search” to mean “any
violation of a reasonable expectation of pri- vacy,” the Katz test misconstrues virtually every one of these
words.

															A

															The Katz test distorts the original
meaning of “searc[h]”—the word in the Fourth Amendment that it
purports to define, see ante , at 5; Smith , supra . Under the Katz test, the government conducts a
search anytime it violates someone’s “reasonable expectation of
privacy.” That is not a normal definition of the word “search.”

															At the founding, “search” did not mean a
violation of someone’s reasonable expectation of privacy. The word
was probably not a term of art, as it does not appear in legal
dictionaries from the era. And its ordinary meaning was the same as
it is today: “ ‘[t]o look over or through for the purpose of
finding something; to explore; to examine by inspection; as, to search the house for a book; to search the wood for a
thief.’ ” Kyllo v. United States , 533 U. S.
27, 32, n. 1 (2001) (quoting N. Webster, An American Dictionary of
the English Language 66 (1828) (reprint 6th ed. 1989)); accord, 2
S. Johnson, A Dictionary of the English Language (5th ed. 1773)
(“Inquiry by looking into every suspected place”); N. Bailey, An
Universal Etymological English Dictionary (22d ed. 1770) (“a
seeking after, a looking for, &c.”); 2 J. Ash, The New and
Complete Dictionary of the English Language (2d ed. 1795) (“An
enquiry, an examination, the act of seeking, an enquiry by looking
into every suspected place; a quest; a pursuit”); T. Sheridan, A
Complete Dictionary of the English Language (6th ed. 1796)
(similar). The word “search” was not associated with “reasonable
expectation of privacy” until Justice Harlan coined that phrase in
1967. The phrase “expectation(s) of privacy” does not appear in the
pre- Katz federal or state case reporters, the papers of
prominent Founders,[ 2 ] early
congressional documents and debates,[ 3 ] collections of early American English texts,[ 4 ] or early American
newspapers.[ 5 ]

															B

															The Katz test strays even further from
the text by focusing on the concept of “privacy.” The word
“privacy” does not appear in the Fourth Amendment (or anywhere else
in the Constitution for that matter). Instead, the Fourth Amendment
references “[t]he right of the people to be secure.” It then
qualifies that right by limiting it to “persons” and three specific
types of property: “houses, papers, and effects.” By connecting the
right to be secure to these four specific objects, “[t]he text of
the Fourth Amendment reflects its close connection to property.” Jones , supra , at 405. “[P]rivacy,” by contrast, “was
not part of the political vocabulary of the [founding]. Instead,
liberty and privacy rights were understood largely in terms of
property rights.” Cloud, Property Is Privacy: Locke and Brandeis in
the Twenty-First Century, 55 Am. Crim. L. Rev. 37, 42
(2018).

															Those who ratified the Fourth Amendment were
quite familiar with the notion of security in property. Security in
property was a prominent concept in English law. See, e.g., 3 W. Blackstone, Commentaries on the Laws of Eng-

															land 288 (1768) (“[E]very man’s house is looked
upon by the law to be his castle”); 3 E. Coke, Institutes of Laws
of England 162 (6th ed. 1680) (“[F]or a man[’]s house is his
Castle, & domus sua cuique est tutissimum refugium [each man’s
home is his safest refuge]”). The political philosophy of John
Locke, moreover, “permeated the 18th-century political scene in
America.” Obergefell v. Hodges , 576 U. S. ___,
___ (2015) (Thomas, J., dissenting) (slip op., at 8). For Locke,
every individual had a property right “in his own person” and in
anything he “removed from the common state [of] Nature” and “mixed
his labour with.” Second Treatise of Civil Government §27 (1690).
Because property is “very unsecure” in the state of nature, §123,
individuals form governments to obtain “a secure enjoyment of their
properties.” §95. Once a government is formed, however, it cannot
be given “a power to destroy that which every one designs to
secure”; it cannot legitimately “endeavour to take away, and
destroy the property of the people,” or exercise “an absolute power
over [their] lives, liberties, and estates.” §222.

															The concept of security in property recognized
by Locke and the English legal tradition appeared throughout the
materials that inspired the Fourth Amendment. In Entick v. Carrington , 19 How. St. Tr. 1029 (C. P. 1765)—a
heralded decision that the founding generation considered “the true
and ultimate expression of constitutional law,” Boyd v. United States , 116 U. S. 616, 626 (1886)—Lord Camden
explained that “[t]he great end, for which men entered into
society, was to secure their property.” 19 How. St. Tr., at 1066.
The American colonists echoed this reasoning in their “widespread
hostility” to the Crown’s writs of assistance[ 6 ]—a practice that inspired the Revolution and
became “[t]he driving force behind the adoption of the [Fourth]
Amendment.” United States v. Verdugo-Urquidez , 494
U. S. 259, 266 (1990). Prominent colonists decried the writs
as destroying “ ‘domestic security’ ” by permitting broad
searches of homes. M. Smith, The Writs of Assistance Case 475
(1978) (quoting a 1772 Boston town meeting); see also id., at 562 (complaining that “ ‘every householder in this
province, will necessarily become less secure than he was
before this writ’ ” (quoting a 1762 article in the Boston
Gazette)); id., at 493 (complaining that the writs were
“ ‘expressly contrary to the common law, which ever regarded a
man’s house as his castle, or a place of perfect
security’ ” (quoting a 1768 letter from John Dickinson)). John
Otis, who argued the famous Writs of Assistance case, contended
that the writs violated “ ‘the fundamental Principl[e] of
Law’ ” that “ ‘[a] Man who is quiet, is as secure in his
House, as a Prince in his Castle.’ ” Id., at 339
(quoting John Adam’s notes). John Adams attended Otis’ argument and
later drafted Article XIV of the Massachusetts
Constitution,[ 7 ] which served
as a model for the Fourth Amendment. See Clancy, The Framers’
Intent: John Adams, His Era, and the Fourth Amendment, 86 Ind.
L. J. 979, 982 (2011); Donahue, The Original Fourth Amendment,
83 U. Chi. L. Rev. 1181, 1269 (2016)

															(Donahue). Adams agreed that “[p]roperty must be
secured, or liberty cannot exist.” Discourse on Davila, in 6 The
Works of John Adams 280 (C. Adams ed. 1851).

															Of course, the founding generation understood
that, by securing their property, the Fourth Amendment would often
protect their privacy as well. See, e.g., Boyd , supra , at 630 (explaining that searches of houses invade
“the privacies of life”); Wilkes v. Wood , 19 How. St.
Tr. 1153, 1154 (C. P. 1763) (argument of counsel contending
that seizures of papers implicate “our most private concerns”). But
the Fourth Amendment’s attendant protection of privacy does not
justify Katz ’s elevation of privacy as the sine qua
non of the Amendment. See T. Clancy, The Fourth Amendment:
Its History and Interpretation §3.4.4, p. 78 (2008) (“[The Katz test] confuse[s] the reasons for exercising the
protected right with the right itself. A purpose of exercising
one’s Fourth Amendment rights might be the desire for privacy, but
the individual’s motivation is not the right protected”); cf. United States v. Gonzalez- Lopez , 548 U. S. 140,
145 (2006) (rejecting “a line of reasoning that ‘abstracts from the
right to its purposes, and then eliminates the right’ ”). As
the majority opinion in Katz recognized, the Fourth
Amendment “cannot be translated into a general constitutional
‘right to privacy,’ ” as its protections “often have nothing
to do with privacy at all.” 389 U. S., at 350. Justice
Harlan’s focus on privacy in his concurrence—an opinion that was
issued between Griswold v. Connecticut , 381
U. S. 479 (1965), and Roe v. Wade , 410
U. S. 113 (1973)—reflects privacy’s status as the organizing
constitutional idea of the 1960’s and 1970’s. The organizing
constitutional idea of the founding era, by contrast, was
property.

															C

															In shifting the focus of the Fourth Amendment
from property to privacy, the Katz test also reads the words
“persons, houses, papers, and effects” out of the text. At its
broadest formulation, the Katz test would find a search
“ wherever an individual may harbor a reasonable ‘expectation
of privacy.’ ” Terry , 392 U. S., at 9 (emphasis
added). The Court today, for example, does not ask whether
cell-site location records are “persons, houses, papers, [or]
effects” within the meaning of the Fourth Amendment.[ 8 ] Yet “persons, houses, papers, and effects”
cannot mean “anywhere” or “anything.” Katz ’s catchphrase
that “the Fourth Amendment protects people, not places,” is not a
serious attempt to reconcile the constitutional text. See Carter , 525 U. S., at 98, n. 3 (opinion of Scalia,
J.). The Fourth Amendment obviously protects people; “[t]he
question . . . is what protection it affords to those
people.” Katz , 389 U. S., at 361 (Harlan, J.,
concurring). The Founders decided to protect the people from
unreasonable searches and seizures of four specific things—persons,
houses, papers, and effects. They identified those four categories
as “the objects of privacy protection to which the Constitution would extend, leaving further expansion to the
good judgment . . . of the people through their
representatives in the legislature.” Carter , supra ,
at 97–98 (opinion of Scalia, J.).

															This limiting language was important to the
founders. Madison’s first draft of the Fourth Amendment used a
different phrase: “their persons, their houses, their papers, and
their other property .” 1 Annals of Cong. 452 (1789)

															(emphasis added). In one of the few changes made
to Madison’s draft, the House Committee of Eleven changed “other
property” to “effects.” See House Committee of Eleven Report (July
28, 1789), in N. Cogan, The Complete Bill of Rights 334 (2d ed.
2015). This change might have narrowed the Fourth Amendment by
clarifying that it does not protect real property (other than
houses). See Oliver v. United States , 466 U. S.
170, 177, and n. 7 (1984); Davies, Recovering the Original
Fourth Amendment, 98 Mich. L. Rev. 547, 709–714 (1999)
(Davies). Or the change might have broadened the Fourth Amendment
by clarifying that it protects commercial goods, not just personal
possessions. See Donahue 1301. Or it might have done both. Whatever
its ultimate effect, the change reveals that the Founders
understood the phrase “persons, houses, papers, and effects” to be
an important measure of the Fourth Amendment’s overall scope. See
Davies 710. The Katz test, however, displaces and renders
that phrase entirely “superfluous.” Jones , 565 U. S.,
at 405.

															D

															“[P]ersons, houses, papers, and effects” are
not the only words that the Katz test reads out of the
Fourth Amendment. The Fourth Amendment specifies that the people
have a right to be secure from unreasonable searches of “their”
persons, houses, papers, and effects. Although phrased in the
plural, “[t]he obvious meaning of [‘their’] is that each person has the right to be secure against unreasonable searches and
seizures in his own person, house, papers, and effects.” Carter , supra , at 92 (opinion of Sca- lia, J.); see
also District of Columbia v. Heller , 554 U. S.
570, 579 (2008) (explaining that the Constitution uses the plural
phrase “the people” to “refer to individual rights, not
‘collective’ rights”). Stated differently, the word “their” means,
at the very least, that individuals do not have Fourth Amendment
rights in someone else’s property. See Carter , supra , at 92–94 (opinion of Scalia, J.). Yet, under the Katz test, individuals can have a reasonable expectation of
privacy in another person’s property. See, e.g., Carter , 525
U. S., at 89 (majority opinion) (“[A] person may have a
legitimate expectation of privacy in the house of someone else”).
Until today, our precedents have not acknowledged that individuals
can claim a reasonable expectation of privacy in someone else’s
business records. See ante, at 2 (Kennedy, J., dissenting).
But the Court erases that line in this case, at least for cell-site
location records. In doing so, it confirms that the Katz test does not necessarily require an individual to prove that the
government searched his person, house, paper, or effect.

															Carpenter attempts to argue that the cell-site
records are, in fact, his “papers,” see Brief for Petitioner 32–35;
Reply Brief 14–15, but his arguments are unpersuasive, see ante, at 12–13 (opinion of Kennedy, J.); post, at
20–23 (Alito, J., dissenting). Carpenter stipulated below that the
cell-site records are the business records of Sprint and MetroPCS.
See App. 51. He cites no property law in his briefs to this Court,
and he does not explain how he has a property right in the
companies’ records under the law of any jurisdiction at any point
in American history. If someone stole these records from Sprint or
MetroPCS, Carpenter does not argue that he could recover in a
traditional tort action. Nor do his contracts with Sprint and
MetroPCS make the records his, even though such provisions could
exist in the marketplace. Cf., e.g., Google Terms of
Service, https://policies.google.com/terms (“Some of our Services
allow you to upload, submit, store, send or receive content. You
retain ownership of any intellectual property rights that you hold
in that content. In short, what belongs to you stays yours”).

															Instead of property, tort, or contract law,
Carpenter relies on the federal Telecommunications Act of 1996 to
demonstrate that the cell site records are his papers. The
Telecommunications Act generally bars cell-phone companies from
disclosing customers’ cell site location information to the public.
See 47 U. S. C. §222(c). This is sufficient to make the
records his, Carpenter argues, because the Fourth Amendment merely
requires him to identify a source of “positive law” that “protects
against access by the public without consent.” Brief for Petitioner
32–33 (citing Baude & Stern, The Positive Law Model of the
Fourth Amendment, 129 Harv. L. Rev. 1821, 1825–1826 (2016);
emphasis deleted).

															Carpenter is mistaken. To come within the text
of the Fourth Amendment, Carpenter must prove that the cell-site
records are his ; positive law is potentially relevant only
insofar as it answers that question. The text of the Fourth
Amendment cannot plausibly be read to mean “any violation of
positive law” any more than it can plausibly be read to mean “any
violation of a reasonable expectation of privacy.”

															Thus, the Telecommunications Act is insufficient
because it does not give Carpenter a property right in the
cell-site records. Section 222, titled “Privacy of customer
information,” protects customers’ privacy by preventing cell-phone
companies from disclosing sensitive information about them. The
statute creates a “duty to protect the confidentiality” of
information relating to customers, §222(a), and creates “[p]rivacy
requirements” that limit the disclosure of that information,
§222(c)(1). Nothing in the text pre-empts state property law or
gives customers a property interest in the companies’ business
records (assuming Congress even has that authority).[ 9 ] Although §222 “protects the interests of
individuals against wrongful uses or disclosures of personal data,
the rationale for these legal protections has not historically been
grounded on a perception that people have property rights in
personal data as such.” Samuelson, Privacy as Intellectual
Property? 52 Stan. L. Rev. 1125, 1130–1131 (2000) (footnote
omitted). Any property rights remain with the companies.

															E

															The Katz test comes closer to the text
of the Fourth Amendment when it asks whether an expectation of pri-
vacy is “reasonable,” but it ultimately distorts that term as well.
The Fourth Amendment forbids “unreasonable searches.” In other
words, reasonableness determines the legality of a search, not
“whether a search . . . within the meaning of the
Constitution has occurred .” Carter , 525 U. S.,
at 97 (opinion of Scalia, J.) (internal quotation marks
omitted).

															Moreover, the Katz test invokes the
concept of reason- ableness in a way that would be foreign to the
ratifiers of the Fourth Amendment. Originally, the word “unreason-
able” in the Fourth Amendment likely meant “against reason”—as in
“against the reason of the common law.” See Donahue 1270–1275;
Davies 686–693; California v. Acevedo , 500 U. S.
565, 583 (1991) (Scalia, J., concurring in judgment). At the
founding, searches and seizures were

															regulated by a robust body of common-law rules.
See generally W. Cuddihy, The Fourth Amendment: Origins and
Original Meaning 602–1791 (2009); e.g., Wilson v. Arkansas , 514 U. S. 927, 931–936 (1995) (discussing the
common-law knock-and-announce rule). The search-and-seizure
practices that the Founders feared most—such as general
warrants—were already illegal under the common law, and jurists
such as Lord Coke described violations of the common law as
“against reason.” See Donahue 1270–1271, and n. 513. Locke,
Blackstone, Adams, and other influential figures shortened the
phrase “against reason” to “unreasonable.” See id., at
1270–1275. Thus, by prohibiting “unreasonable” searches and
seizures in the Fourth Amendment, the Founders ensured that the
newly created Congress could not use legislation to abolish the
established common-law rules of search and seizure. See T. Cooley,
Constitutional Limitations *303 (2d ed. 1871); 3 J. Story,
Commentaries on the Constitution of the United States §1895,
p. 748 (1833).

															Although the Court today maintains that its
decision is based on “Founding-era understandings,” ante, at
6, the Founders would be puzzled by the Court’s conclusion as well
as its reasoning. The Court holds that the Government unreasonably
searched Carpenter by subpoenaing the cell-site records of Sprint
and MetroPCS without a warrant. But the Founders would not
recognize the Court’s “warrant requirement.” Ante, at 21.
The common law required warrants for some types of searches and
seizures, but not for many others. The relevant rule depended on
context. See Acevedo , supra , at 583–584 (opinion of
Scalia, J.); Amar, Fourth Amendment First Principles, 107 Harv. L.
Rev. 757, 763–770 (1994); Davies 738–739. In cases like this one, a
subpoena for third-party documents was not a “search” to begin
with, and the common law did not limit the government’s authority
to subpoena third parties. See post, at 2–12 (Alito, J.,
dissenting). Suffice it to say, the Founders would be confused by
this Court’s transformation of their common-law protection of
property into a “warrant requirement” and a vague inquiry into
“reasonable expectations of privacy.”

															III

															That the Katz test departs so far from
the text of the Fourth Amendment is reason enough to reject it. But
the Katz test also has proved unworkable in practice.
Jurists and commentators tasked with deciphering our jurisprudence
have described the Katz regime as “an unpredictable jumble,”
“a mass of contradictions and obscurities,” “all over the map,”
“riddled with inconsistency and incoherence,” “a series of
inconsistent and bizarre results that [the Court] has left entirely
undefended,” “unstable,” “chameleon-like,” “ ‘notoriously
unhelpful,’ ” “a conclusion rather than a starting point for
analysis,” “distressingly unmanageable,” “a dismal failure,”
“flawed to the core,” “unadorned fiat,” and “inspired by the kind
of logic that produced Rube Goldberg’s bizarre
contraptions.”[ 10 ] Even
Justice Harlan, four years after penning his concurrence in Katz , confessed that the test encouraged “the substitution
of words for analysis.” United States v. White , 401
U. S. 745, 786 (1971) (dissenting opinion).

															After 50 years, it is still unclear what
question the Katz test is even asking. This Court has
steadfastly declined to elaborate the relevant considerations or
identify any meaningful constraints. See, e.g., ante, at 5
(“[N]o single rubric definitively resolves which expectations of
privacy are entitled to protection”); O’Connor v. Ortega , 480 U. S. 709, 715 (1987) (plurality opinion)
(“We have no talisman that determines in all cases those privacy
expectations that society is prepared to accept as reasonable”); Oliver , 466 U. S., at 177 (“No single factor determines
whether an individual legitimately may claim under the Fourth
Amendment that a place should be free of government
intrusion”).

															Justice Harlan’s original formulation of the Katz test appears to ask a descriptive question: Whether a
given expectation of privacy is “one that society is prepared to
recognize as ‘reasonable.’ ” 389 U. S., at 361. As
written, the Katz test turns on society’s actual, current
views about the reasonableness of various expectations of
privacy.

															But this descriptive understanding presents
several problems. For starters, it is easily circumvented. If, for
example, “the Government were suddenly to announce on nationwide
television that all homes henceforth would be subject to
warrantless entry,” individuals could not realistically expect
privacy in their homes. Smith , 442 U. S., at 740,
n. 5; see also Chemerinsky, Rediscovering Brandeis’s

															Right to Privacy, 45 Brandeis L. J. 643,
650 (2007) (“[Under Katz, t]he government seemingly can deny
privacy just by letting people know in advance not to expect any”).
A purely descriptive understanding of the Katz test also
risks “circular[ity].” Kyllo , 533 U. S., at 34. While
this Court is supposed to base its decisions on society’s
expectations of privacy, society’s expectations of privacy are, in
turn, shaped by this Court’s decisions. See Posner, The Uncertain
Protection of Privacy by the Supreme Court, 1979 S. Ct. Rev.
173, 188 (“[W]hether [a person] will or will not have [a
reasonable] expectation [of privacy] will depend on what the legal
rule is”).

															To address this circularity problem, the Court
has insisted that expectations of privacy must come from outside
its Fourth Amendment precedents, “either by reference to concepts
of real or personal property law or to understandings that are
recognized and permitted by society.” Rakas v. Illinois , 439 U. S. 128, 144, n. 12 (1978). But
the Court’s supposed reliance on “real or personal property law”
rings hollow. The whole point of Katz was to
“ ‘discredi[t]’ ” the relationship between the Fourth
Amendment and property law, 389 U. S., at 353, and this Court
has repeatedly downplayed the importance of property law under the Katz test, see, e.g., United States v. Salvucci , 448 U. S. 83, 91 (1980) (“[P]roperty rights
are neither the beginning nor the end of this Court’s inquiry
[under Katz ]”); Rawlings v. Kentucky , 448
U. S. 98, 105 (1980) (“[This Court has] emphatically rejected
the notion that ‘arcane’ concepts of property law ought to control
the ability to claim the protections of the Fourth Amendment”).
Today, for example, the Court makes no mention of property law,
except to reject its relevance. See ante, at 5, and
n. 1.

															As for “understandings that are recognized or
permitted in society,” this Court has never answered even the most
basic questions about what this means. See Kerr, Four Models of
Fourth Amendment Protection, 60 Stan. L. Rev. 503, 504–505
(2007). For example, our precedents do not explain who is included
in “society,” how we know what they “recogniz[e] or permi[t],” and
how much of society must agree before something constitutes an
“understanding.”

															Here, for example, society might prefer a
balanced regime that prohibits the Government from obtaining
cell-site location information unless it can persuade a neutral
magistrate that the information bears on an ongoing criminal
investigation. That is precisely the regime Congress created under
the Stored Communications Act and Telecommunications Act. See 47
U. S. C. §222(c)(1); 18 U. S. C.
§§2703(c)(1)(B), (d). With no sense of irony, the Court invalidates
this regime today—the one that society actually created “in the
form of its elected representatives in Congress.” 819 F. 3d
880, 890 (2016).

															Truth be told, this Court does not treat the Katz test as a descriptive inquiry. Although the Katz test is phrased in descriptive terms about society’s views, this
Court treats it like a normative question—whether a particular
practice should be considered a search under the Fourth
Amendment. Justice Harlan thought this was the best way to
understand his test. See White , 401 U. S., at 786
(dissenting opinion) (explaining that courts must assess the
“desirability” of privacy expectations and ask whether courts
“should” recognize them by “balanc[ing]” the “impact on the
individual’s sense of security . . . against the utility
of the conduct as a technique of law enforcement”). And a normative
understanding is the only way to make sense of this Court’s
precedents, which bear the hallmarks of subjective policymaking
instead of neutral legal decisionmaking. “[T]he only thing the past
three decades have established about the Katz test” is that
society’s expectations of privacy “bear an uncanny resemblance to
those expectations of privacy that this Court considers
reasonable.” Carter , 525 U. S., at 97 (opinion of
Scalia, J.). Yet, “[t]hough we know ourselves to be eminently
reasonable, self-awareness of eminent reasonableness is not really
a substitute for democratic election.” Sosa v. Alvarez-Machain , 542 U. S. 692, 750 (2004) (Scalia, J.,
concurring in part and concurring in judgment).

															*  *  *

															In several recent decisions, this Court has
declined to apply the Katz test because it threatened to
narrow the original scope of the Fourth Amendment. See Grady v. North Carolina , 575 U. S. ___, ___ (2015) ( per
curiam ) (slip op., at 3); Florida v. Jardines ,
569 U. S. 1, 5 (2013); Jones , 565 U. S., at
406–407. But as today’s decision demonstrates, Katz can also
be invoked to expand the Fourth Amendment beyond its original
scope. This Court should not tolerate errors in either direction.
“The People, through ratification, have already weighed the policy
tradeoffs that constitutional rights entail.” Luis v. United States , 578 U. S. ___, ___ (2016) (Thomas, J.,
concurring in judgment) (slip op., at 10). Whether the rights they
ratified are too broad or too narrow by modern lights, this Court
has no authority to unilaterally alter the document they
approved.

															Because the Katz test is a failed
experiment, this Court is dutybound to reconsider it. Until it
does, I agree with my dissenting colleagues’ reading of our
precedents. Accordingly, I respectfully dissent. Notes 1 Justice Brandeis authored
the principal dissent in Olmstead . He consulted the
“underlying purpose,” rather than “the words of the [Fourth]
Amendment,” to conclude that the wiretap was a search. 277
U. S., at 476. In Justice Brandeis’ view, the Framers
“recognized the significance of man’s spiritual nature, of his
feelings and of his intellect” and “sought to protect Americans in
their beliefs, their thoughts, their emotions and their
sensations.” Id., at 478. Thus, “every unjustifiable
intrusion by the Government upon the privacy of the individual,
whatever the means employed,” should constitute an unreasonable
search under the Fourth Amendment. Ibid. 2 National Archives,
Library of Congress, Founders Online, https://founders.archives.gov
(all Internet materials as last visited June 18,
2018). 3 A Century of Lawmaking
For A New Nation, U. S. Congressional Documents and Debates,
1774–1875 (May 1, 2003),
https://memory.loc.gov/ammem/amlaw/lawhome.html. 4 Corpus of Historical
American English, https://corpus.byu.edu/coha; Google Books
(American), https://googlebooks.byu.edu/x.asp; Corpus of Founding
Era American English, https://lawncl.byu.edu/cofea. 5 Readex, America’s
Historical Newspapers (2018),
https://www.readex.com/content/americas-historical-newspapers. 6 Writs of assistance were
“general warrants” that gave “customs officials blanket authority
to search where they pleased for goods imported in violation of the
British tax laws.” Stanford v. Texas , 379 U. S.
476, 481 (1965). 7 “Every subject has a
right to be secure from all unreasonable searches and seizures of
his person, his house, his papers, and all his possessions. All
warrants, therefore, are contrary to right, if the cause or
foundation of them be not previously supported by oath or
affirmation, and if the order in the warrant to a civil officer, to
make search in suspected places, or to arrest one or more suspected
persons, or to seize their property, be not accompanied with a
special designation of the person or objects of search, arrest, or
seizure; and no warrant ought to be issued but in cases, and with
the formalities prescribed by the laws.” Mass. Const., pt. I, Art.
XIV (1780). 8 The answer to that
question is not obvious. Cell-site location records are business
records that mechanically collect the interactions between a
person’s cell phone and the company’s towers; they are not private
papers and do not reveal the contents of any communications. Cf.
Schnapper, Unreasonable Searches and Seizures of Papers, 71 Va.
L. Rev. 869, 923–924 (1985) (explaining that business records
that do not reveal “personal or speech-related confidences” might
not satisfy the original meaning of “papers”). 9 Carpenter relies on an
order from the Federal Communications Commission (FCC), which
weakly states that “ ‘ [t]o the extent [a customer’s
location information] is property, . . . it is better
understood as belonging to the customer, not the carrier.’ ”
Brief for Petitioner 34, and n. 23 (quoting 13 FCC Rcd. 8061,
8093 ¶43 (1998); emphasis added). But this order was vacated by the
Court of Appeals for the Tenth Circuit. U. S. West,
Inc. v. FCC , 182 F. 3d 1224, 1240 (1999). Notably,
the carrier in that case argued that the FCC’s regulation of
customer information was a taking of its property. See id., at 1230. Although the panel majority had no occasion to
address this argument, see id., at 1239, n. 14, the
dissent concluded that the carrier had failed to prove the
information was “property” at all, see id., at 1247–1248
(opinion of Briscoe, J.). 10 Kugler & Strahilevitz, Actual
Expectations of Privacy, Fourth Amendment Doctrine, and the Mosaic
Theory, 2015 S. Ct. Rev. 205, 261; Bradley, Two Models of the
Fourth Amendment, 83 Mich. L. Rev. 1468 (1985); Kerr, Four Models
of Fourth Amendment Protection, 60 Stan. L. Rev. 503, 505 (2007);
Solove, Fourth Amendment Pragmatism, 51 Boston College L. Rev. 1511
(2010); Wasserstom & Seidman, The Fourth Amendment as
Constitutional Theory, 77 Geo. L. J. 19, 29 (1988); Colb, What
Is a Search? Two Conceptual Flaws in Fourth Amendment Doctrine and
Some Hints of a Remedy, 55 Stan. L. Rev. 119, 122 (2002); Clancy,
The Fourth Amendment: Its History and Interpretation §3.3.4,
p. 65 (2008); Minnesota v. Carter , 525
U. S. 83, 97 (1998) (Scalia, J., dissenting); State v. Campbell , 306 Ore. 157, 164, 759 P.2d
1040 , 1044 (1988); Wilkins, Defining the “Reasonable
Expectation of Privacy”: an Emerging Tripartite Analysis, 40 Vand.
L. Rev. 1077, 1107 (1987); Yeager, Search, Seizure and the Positive
Law: Expectations of Privacy Outside the Fourth Amendment, 84 J.
Crim. L. & C. 249, 251 (1993); Thomas, Time Travel,
Hovercrafts, and the Framers: James Madison Sees the Future and
Rewrites the Fourth Amendment, 80 Notre Dame L. Rev. 1451, 1500
(2005); Rakas v. Illinois , 439 U. S. 128, 165
(1978) (White, J., dissenting); Cloud, Rube Goldberg Meets the
Constitution: The Supreme Court, Technology, and the Fourth
Amendment, 72 Miss. L. J. 5, 7 (2002). SUPREME COURT OF THE UNITED STATES

															_________________

															No. 16–402

															_________________

															TIMOTHY IVORY CARPENTER, PETITIONER v. UNITED STATES

															on writ of certiorari to the united states
court of appeals for the sixth circuit

															[June 22, 2018]

															Justice Alito, with whom Justice Thomas joins,
dissenting.

															I share the Court’s concern about the effect of
new technology on personal privacy, but I fear that today’s
decision will do far more harm than good. The Court’s reasoning
fractures two fundamental pillars of Fourth Amendment law, and in
doing so, it guarantees a blizzard of litigation while threatening
many legitimate and valuable investigative practices upon which law
enforcement has rightfully come to rely.

															First, the Court ignores the basic distinction
between an actual search (dispatching law enforcement officers to
enter private premises and root through private papers and effects)
and an order merely requiring a party to look through its own
records and produce specified documents. The former, which intrudes
on personal privacy far more deeply, requires probable cause; the
latter does not. Treating an order to produce like an actual
search, as today’s decision does, is revolutionary. It violates
both the original understanding of the Fourth Amendment and more
than a century of Supreme Court precedent. Unless it is somehow
restricted to the particular situation in the present case, the
Court’s move will cause upheaval. Must every grand jury subpoena duces tecum be supported by probable cause? If so,
investigations of terrorism, political corruption, white-collar
crime, and many other offenses will be stymied. And what about
subpoenas and other document-production orders issued by
administrative agencies? See, e.g. , 15 U. S. C.
§57b–1(c) (Federal Trade Commission); §§77s(c), 78u(a)–(b)
(Securities and Exchange Commission); 29 U. S. C. §657(b)
(Occupational Safety and Health Administration); 29 CFR
§1601.16(a)(2) (2017) (Equal Employment Opportunity
Commission).

															Second, the Court allows a defendant to object
to the search of a third party’s property. This also is
revolutionary. The Fourth Amendment protects “[t]he right of the
people to be secure in their persons, houses, papers, and
effects” (emphasis added), not the persons, houses, papers, and
effects of others. Until today, we have been careful to heed this
fundamental feature of the Amendment’s text. This was true when the
Fourth Amendment was tied to property law, and it remained true
after Katz v. United States , 389 U. S. 347
(1967), broadened the Amendment’s reach.

															By departing dramatically from these fundamental
principles, the Court destabilizes long-established Fourth
Amendment doctrine. We will be making repairs—or picking up the
pieces—for a long time to come.

															I

															Today the majority holds that a court order
requiring the production of cell-site records may be issued only
after the Government demonstrates probable cause. See ante ,
at 18. That is a serious and consequential mistake. The Court’s
holding is based on the premise that the order issued in this case
was an actual “search” within the meaning of the Fourth Amendment,
but that premise is inconsistent with the original meaning of the
Fourth Amendment and with more than a century of precedent.

															A

															The order in this case was the functional
equivalent of a subpoena for documents, and there is no evidence
that these writs were regarded as “searches” at the time of the
founding. Subpoenas duces tecum and other forms of
compulsory document production were well known to the founding
generation. Blackstone dated the first writ of subpoena to the
reign of King Richard II in the late 14th century, and by the end
of the 15th century, the use of such writs had “become the daily
practice of the [Chancery] court.” 3 W. Blackstone, Commentaries on
the Laws of England 53 (G. Tucker ed. 1803) (Blackstone). Over the
next 200 years, subpoenas would grow in prominence and power in
tandem with the Court of Chancery, and by the end of Charles II’s
reign in 1685, two important innovations had occurred.

															First, the Court of Chancery developed a new
species of subpoena. Until this point, subpoenas had been used
largely to compel attendance and oral testimony from witnesses;
these subpoenas correspond to today’s subpoenas ad
testificandum . But the Court of Chancery also improvised a new
version of the writ that tacked onto a regular subpoena an order
compelling the witness to bring certain items with him. By issuing
these so-called subpoenas duces tecum , the Court of Chancery
could compel the production of papers, books, and other forms of
physical evidence, whether from the parties to the case or from
third parties. Such subpoenas were sufficiently commonplace by 1623
that a leading treatise on the practice of law could refer in
passing to the fee for a “ Sub pœna of Ducas tecum ”
(seven shillings and two pence) without needing to elaborate
further. T. Powell, The Attourneys Academy 79 (1623). Subpoenas duces tecum would swell in use over the next century as the
rules for their application became ever more developed and
definite. See, e.g. , 1 G. Jacob, The Compleat
Chancery-Practiser 290 (1730) (“The Subpoena duces tecum is
awarded when the Defendant has confessed by his Answer that he hath
such Writings in his Hands as are prayed by the Bill to be
discovered or brought into Court”).

															Second, although this new species of subpoena
had its origins in the Court of Chancery, it soon made an
appearance in the work of the common-law courts as well. One court
later reported that “[t]he Courts of Common law . . .
employed the same or similar means . . . from the time of
Charles the Second at least.” Amey v. Long , 9 East.
473, 484, 103 Eng. Rep. 653, 658 (K. B. 1808).

															By the time Blackstone published his
Commentaries on the Laws of England in the 1760’s, the use of
subpoenas duces tecum had bled over substantially from the
courts of equity to the common-law courts. Admittedly, the
transition was still incomplete: In the context of jury trials, for
example, Blackstone complained about “the want of a compulsive
power for the production of books and papers belonging to the
parties.” Blackstone 381; see also, e.g. , Entick v. Carrington , 19 State Trials 1029, 1073 (K. B. 1765) (“I
wish some cases had been shewn, where the law forceth evidence out
of the owner’s custody by process. [But] where the adversary has by
force or fraud got possession of your own proper evidence, there is
no way to get it back but by action”). But Blackstone found some
comfort in the fact that at least those documents “[i]n the hands
of third persons . . . can generally be obtained by rule
of court, or by adding a clause of requisition to the writ of subpoena , which is then called a subpoena duces
tecum .” Blackstone 381; see also, e.g. , Leeds v. Cook , 4 Esp. 256, 257, 170 Eng. Rep. 711 (N. P. 1803)
(third-party subpoena duces tecum ); Rex v. Babb , 3 T. R. 579, 580, 100 Eng. Rep. 743, 744
(K. B. 1790) (third-party document production). One of the
primary questions outstanding, then, was whether common-law courts
would remedy the “defect[s]” identified by the Commentaries, and
allow parties to use subpoenas duces tecum not only with
respect to third parties but also with respect to each other.
Blackstone 381.

															That question soon found an affirmative answer
on both sides of the Atlantic. In the United States, the First
Congress established the federal court system in the Judiciary Act
of 1789. As part of that Act, Congress authorized “all the said
courts of the United States . . . in the trial of actions
at law, on motion and due notice thereof being given, to require
the parties to produce books or writings in their possession or
power, which contain evidence pertinent to the issue, in cases and
under circumstances where they might be compelled to produce the
same by the ordinary rules of proceeding in chancery.” §15, 1Stat.
82. From that point forward, federal courts in the United States
could compel the production of documents regardless of whether
those documents were held by parties to the case or by third
parties.

															In Great Britain, too, it was soon definitively
established that common-law courts, like their counterparts in
equity, could subpoena documents held either by parties to the case
or by third parties. After proceeding in fits and starts, the
King’s Bench eventually held in Amey v. Long that the
“writ of subpœna duces tecum [is] a writ of compulsory obligation
and effect in the law.” 9 East., at 486, 103 Eng. Rep., at 658.
Writing for a unanimous court, Lord Chief Justice Ellenborough
explained that “[t]he right to resort to means competent to compel
the production of written, as well as oral, testimony seems
essential to the very existence and constitution of a Court of
Common Law.” Id., at 484, 103 Eng. Rep., at 658. Without the
power to issue subpoenas duces tecum , the Lord Chief Justice
observed, common-law courts “could not possibly proceed with due
effect.” Ibid. The prevalence of subpoenas duces tecum at the time of the founding was not limited to the civil context.
In criminal cases, courts and prosecutors were also using the writ
to compel the production of necessary documents. In Rex v. Dixon , 3 Burr. 1687, 97 Eng. Rep. 1047 (K. B. 1765), for
example, the King’s Bench considered the propriety of a subpoena duces tecum served on an attorney named Samuel Dixon. Dixon
had been called “to give evidence before the grand jury of the
county of Northampton” and specifically “to produce three vouchers
. . . in order to found a prosecution by way of
indictment against [his client] Peach . . . for forgery.” Id., at 1687, 97 Eng. Rep., at 1047–1048. Although the court
ultimately held that Dixon had not needed to produce the vouchers
on account of attorney-client privilege, none of the justices
expressed the slightest doubt about the general propriety of
subpoenas duces tecum in the criminal context. See id., at 1688, 97 Eng. Rep., at 1048. As Lord Chief Justice
Ellenborough later explained, “[i]n that case no objection was
taken to the writ, but to the special circumstances under which the
party possessed the papers; so that the Court may be considered as
recognizing the general obligation to obey writs of that
description in other cases.” Amey , supra , at 485, 103
Eng. Rep., at 658; see also 4 J. Chitty, Practical Treatise on the
Criminal Law 185 (1816) (template for criminal subpoena duces
tecum ).

															As Dixon shows, subpoenas duces
tecum were routine in part because of their close association
with grand juries. Early American colonists imported the grand
jury, like so many other common-law traditions, and they quickly
flourished. See United States v. Calandra , 414
U. S. 338, 342–343 (1974). Grand juries were empaneled by the
federal courts almost as soon as the latter were established, and
both they and their state counterparts actively exercised their
wide-ranging common-law authority. See R. Younger, The People’s
Panel 47–55 (1963). Indeed, “the Founders thought the grand jury so
essential . . . that they provided in the Fifth Amendment
that federal prosecution for serious crimes can only be instituted
by ‘a presentment or indictment of a Grand Jury.’ ” Calandra , supra , at 343.

															Given the popularity and prevalence of grand
juries at the time, the Founders must have been intimately familiar
with the tools they used—including compulsory process—to accomplish
their work. As a matter of tradition, grand juries were “accorded
wide latitude to inquire into violations of criminal law,”
including the power to “compel the production of evidence or the
testimony of witnesses as [they] conside[r] appropriate.” Ibid. Long before national independence was achieved, grand
juries were already using their broad inquisitorial powers not only
to present and indict criminal suspects but also to inspect public
buildings, to levy taxes, to supervise the administration of the
laws, to advance municipal reforms such as street repair and bridge
maintenance, and in some cases even to propose legislation.
Younger, supra , at 5–26. Of course, such work depended
entirely on grand juries’ ability to access any relevant
documents.

															Grand juries continued to exercise these broad
inquisitorial powers up through the time of the founding. See Blair v. United States , 250 U. S. 273, 280
(1919) (“At the foundation of our Federal Government the
inquisitorial function of the grand jury and the compulsion of
witnesses were recognized as incidents of the judicial power”). In
a series of lectures delivered in the early 1790’s, Justice James
Wilson crowed that grand juries were “the peculiar boast of the
common law” thanks in part to their wide-ranging authority: “All
the operations of government, and of its ministers and officers,
are within the compass of their view and research.” 2 J. Wilson,
The Works of James Wilson 534, 537 (R. McCloskey ed. 1967). That
reflected the broader insight that “[t]he grand jury’s
investigative power must be broad if its public responsibility is
adequately to be discharged.” Calandra , supra , at
344.

															Compulsory process was also familiar to the
founding generation in part because it reflected “the ancient
proposition of law” that “ ‘ “the public . . .
has a right to every man’s evidence.” ’ ” United
States v. Nixon , 418 U. S. 683, 709 (1974); see
also ante , at 10 (Kennedy, J., dissenting). As early as
1612, “Lord Bacon is reported to have declared that ‘all subjects,
without distinction of degrees, owe to the King tribute and
service, not only of their deed and hand, but of their knowledge
and discovery.’ ” Blair , supra , at 279–280. That
duty could be “onerous at times,” yet the Founders considered it
“necessary to the administration of justice according to the forms
and modes established in our system of government.” Id., at
281; see also Calandra , supra , at 345.

															B

															Talk of kings and common-law writs may seem
out of place in a case about cell-site records and the protections
afforded by the Fourth Amendment in the modern age. But this
history matters, not least because it tells us what was on the
minds of those who ratified the Fourth Amendment and how they
understood its scope. That history makes it abundantly clear that
the Fourth Amendment, as originally understood, did not apply to
the compulsory production of documents at all.

															The Fourth Amendment does not regulate all
methods by which the Government obtains documents. Rather, it
prohibits only those “searches and seizures” of “persons, houses,
papers, and effects” that are “unreasonable.” Consistent with that
language, “at least until the latter half of the 20th century” “our
Fourth Amendment jurisprudence was tied to common-law trespass.” United States v. Jones , 565 U. S. 400, 405
(2012). So by its terms, the Fourth Amendment does not apply to the
compulsory production of documents, a practice that involves
neither any physical intrusion into private space nor any taking of
property by agents of the state. Even Justice Brandeis—a stalwart
proponent of construing the Fourth Amendment liberally—acknowledged
that “under any ordinary construction of language,” “there is no
‘search’ or ‘seizure’ when a defendant is required to produce a
document in the orderly process of a court’s procedure.” Olmstead v. United States , 277 U. S. 438, 476
(1928) (dissenting opinion).[ 1 ]

															Nor is there any reason to believe that the
Founders intended the Fourth Amendment to regulate courts’ use of
compulsory process. American colonists rebelled against the Crown’s
physical invasions of their persons and their property, not against
its acquisition of information by any and all means. As Justice
Black once put it, “[t]he Fourth Amendment was aimed directly at
the abhorred practice of breaking in, ransacking and searching
homes and other buildings and seizing people’s personal belongings
without warrants issued by magistrates.” Katz , 389
U. S., at 367 (dissenting opinion). More recently, we have
acknowledged that “the Fourth Amendment was the founding
generation’s response to the reviled ‘general warrants’ and ‘writs
of assistance’ of the colonial era, which allowed British officers
to rummage through homes in an unrestrained search for evidence of
criminal activity.” Riley v. California , 573
U. S. ___, ___ (2014) (slip op., at 27).

															General warrants and writs of assistance were
noxious not because they allowed the Government to acquire evidence
in criminal investigations, but because of the means by
which they permitted the Government to acquire that evidence. Then,
as today, searches could be quite invasive. Searches generally
begin with officers “mak[ing] nonconsensual entries into areas not
open to the public.” Donovan v. Lone Steer, Inc. , 464
U. S. 408, 414 (1984). Once there, officers are necessarily in
a position to observe private spaces generally shielded from the
public and discernible only with the owner’s consent. Private area
after private area becomes exposed to the officers’ eyes as they
rummage through the owner’s property in their hunt for the object
or objects of the search. If they are searching for documents,
officers may additionally have to rifle through many other
papers—potentially filled with the most intimate details of a
person’s thoughts and life—before they find the specific
information they are seeking. See Andresen v. Maryland , 427 U. S. 463, 482, n. 11 (1976). If
anything sufficiently incriminating comes into view, officers seize
it. Horton v. California , 496 U. S. 128, 136–137
(1990). Physical destruction always lurks as an underlying
possibility; “officers executing search warrants on occasion must
damage property in order to perform their duty.” Dalia v. United States , 441 U. S. 238, 258 (1979); see, e.g. , United States v. Ramirez , 523 U. S.
65, 71–72 (1998) (breaking garage window); United States v. Ross , 456 U. S. 798, 817–818 (1982) (ripping open car
upholstery); Brown v. Battle Creek Police Dept. , 844
F. 3d 556, 572 (CA6 2016) (shooting and killing two pet dogs); Lawmaster v. Ward , 125 F. 3d 1341, 1350,
n. 3 (CA10 1997) (breaking locks).

															Compliance with a subpoena duces tecum requires none of that. A subpoena duces tecum permits a
subpoenaed individual to conduct the search for the relevant
documents himself, without law enforcement officers entering his
home or rooting through his papers and effects. As a result,
subpoenas avoid the many incidental invasions of privacy that
necessarily accompany any actual search. And it was those invasions of privacy—which, although incidental, could often be
extremely intrusive and damaging—that led to the adoption of the
Fourth Amendment.

															Neither this Court nor any of the parties have
offered the slightest bit of historical evidence to support the
idea that the Fourth Amendment originally applied to subpoenas duces tecum and other forms of compulsory process. That is
telling, for as I have explained, these forms of compulsory process
were a feature of criminal (and civil) procedure well known to the
Founders. The Founders would thus have understood that holding the
compulsory production of documents to the same standard as actual
searches and seizures would cripple the work of courts in civil and
criminal cases alike. It would be remarkable to think that, despite
that knowledge, the Founders would have gone ahead and sought to
impose such a requirement. It would be even more incredible to
believe that the Founders would have imposed that requirement
through the inapt vehicle of an amendment directed at different
concerns. But it would blink reality entirely to argue that this
entire process happened without anyone saying the least thing
about it —not during the drafting of the Bill of Rights, not
during any of the subsequent ratification debates, and not for most
of the century that followed. If the Founders thought the Fourth
Amendment applied to the compulsory production of documents, one
would imagine that there would be some founding-era evidence
of the Fourth Amendment being applied to the compulsory production
of documents. Cf. Free Enterprise Fund v. Public Company
Accounting Oversight Bd. , 561 U. S. 477, 505 (2010); Printz v. United States , 521 U. S. 898, 905
(1997). Yet none has been brought to our attention.

															C

															Of course, our jurisprudence has not stood
still since 1791. We now evaluate subpoenas duces tecum and
other forms of compulsory document production under the Fourth
Amendment, although we employ a reasonableness standard that is
less demanding than the requirements for a warrant. But the road to
that doctrinal destination was anything but smooth, and our initial
missteps—and the subsequent struggle to extricate ourselves from
their consequences—should provide an object lesson for today’s
majority about the dangers of holding compulsory process to the
same standard as actual searches and seizures.

															For almost a century after the Fourth Amendment
was enacted, this Court said and did nothing to indicate that it
might regulate the compulsory production of documents. But that
changed temporarily when the Court decided Boyd v. United
States , 116 U. S. 616 (1886), the first—and, until today,
the only—case in which this Court has ever held the compulsory
production of documents to the same standard as actual searches and
seizures.

															The Boyd Court held that a court order
compelling a company to produce potentially incriminating business
records violated both the Fourth and the Fifth Amendments. The
Court acknowledged that “certain aggravating incidents of actual
search and seizure, such as forcible entry into a man’s house and
searching amongst his papers, are wanting” when the Government
relies on compulsory process. Id. , at 622. But it
nevertheless asserted that the Fourth Amendment ought to “be
liberally construed,” id. , at 635, and further reasoned that
compulsory process “effects the sole object and purpose of search
and seizure” by “forcing from a party evidence against himself,” id. , at 622. “In this regard,” the Court concluded, “the
Fourth and Fifth Amendments run almost into each other.” Id. , at 630. Having equated compulsory process with actual
searches and seizures and having melded the Fourth Amendment with
the Fifth, the Court then found the order at issue unconstitutional
because it compelled the production of property to which the
Government did not have superior title. See id. , at
622–630.

															In a concurrence joined by Chief Justice Waite,
Justice Miller agreed that the order violated the Fifth Amendment, id. , at 639, but he strongly protested the majority’s
invocation of the Fourth Amendment. He explained: “[T]here is no
reason why this court should assume that the action of the court
below, in requiring a party to produce certain papers
. . . , authorizes an unreasonable search or seizure of
the house, papers, or effects of that party. There is in fact no
search and no seizure.” Ibid. “If the mere service of a
notice to produce a paper . . . is a search,” Justice
Miller concluded, “then a change has taken place in the meaning of
words, which has not come within my reading, and which I think was
unknown at the time the Constitution was made.” Id., at
641.

															Although Boyd was replete with stirring
rhetoric, its reasoning was confused from start to finish in a way
that ultimately made the decision unworkable. See 3 W. LaFave, J.
Israel, N. King, & O. Kerr, Criminal Procedure §8.7(a) (4th ed.
2015). Over the next 50 years, the Court would gradually roll back Boyd ’s erroneous conflation of compulsory process with
actual searches and seizures.

															That effort took its first significant stride in Hale v. Henkel , 201 U. S. 43 (1906), where the
Court found it “quite clear” and “conclusive” that “the search and
seizure clause of the Fourth Amendment was not intended to
interfere with the power of courts to compel, through a subpœna
duces tecum , the production, upon a trial in court, of
documentary evidence.” Id., at 73. Without that writ, the
Court recognized, “it would be ‘utterly impossible to carry on the
administration of justice.’ ” Ibid. Hale , however, did not entirely liberate
subpoenas duces tecum from Fourth Amendment constraints.
While refusing to treat such subpoenas as the equivalent of actual
searches, Hale concluded that they must not be unreasonable.
And it held that the subpoena duces tecum at issue was “far
too sweeping in its terms to be regarded as reasonable.” Id., at 76. The Hale Court thus left two critical
questions unanswered: Under the Fourth Amendment, what makes the
compulsory production of documents “reasonable,” and how does that
standard differ from the one that governs actual searches and
seizures?

															The Court answered both of those questions
definitively in Oklahoma Press Publishing Co. v. Walling , 327 U. S. 186 (1946), where we held that the
Fourth Amendment regulates the compelled production of documents,
but less stringently than it does full-blown searches and seizures. Oklahoma Press began by admitting that the Court’s opinions
on the subject had “perhaps too often . . . been
generative of heat rather than light,” “mov[ing] with variant
direction” and sometimes having “highly contrasting” “emphasis and
tone.” Id., at 202. “The primary source of misconception
concerning the Fourth Amendment’s function” in this context, the
Court explained, “lies perhaps in the identification of cases
involving so-called ‘figurative’ or ‘constructive’ search with
cases of actual search and seizure.” Ibid. But the Court
held that “the basic distinction” between the compulsory production
of documents on the one hand, and actual searches and seizures on
the other, meant that two different standards had to be applied. Id., at 204.

															Having reversed Boyd ’s conflation of the
compelled production of documents with actual searches and
seizures, the Court then set forth the relevant Fourth Amendment
standard for the former. When it comes to “the production of
corporate or other business records,” the Court held that the
Fourth Amendment “at the most guards against abuse only by way of
too much indefiniteness or breadth in the things required to be
‘particularly described,’ if also the inquiry is one the demanding
agency is authorized by law to make and the materials specified are
relevant.” Oklahoma Press , supra , at 208. Notably,
the Court held that a showing of probable cause was not necessary
so long as “the investigation is authorized by Congress, is for a
purpose Congress can order, and the documents sought are relevant
to the inquiry.” Id., at 209.

															Since Oklahoma Press , we have
consistently hewed to that standard. See, e.g. , Lone
Steer, Inc. , 464 U. S., at 414–415; United States v. Miller , 425 U. S. 435, 445–446 (1976); California
Bankers Assn. v. Shultz , 416 U. S. 21, 67 (1974); United States v. Dionisio , 410 U. S. 1, 11–12
(1973); See v. Seattle , 387 U. S. 541, 544
(1967); United States v. Powell , 379 U. S. 48,
57–58 (1964); McPhaul v. United States , 364
U. S. 372, 382–383 (1960); United States v. Morton
Salt Co. , 338 U. S. 632, 652–653 (1950); cf. McLane
Co. v. EEOC , 581 U. S. ___, ___ (2017) (slip op.,
at 11). By applying Oklahoma Press and thereby respecting
“the traditional distinction between a search warrant and a
subpoena,” Miller , supra , at 446, this Court has
reinforced “the basic compromise” between “the public interest” in
every man’s evidence and the private interest “of men to be free
from officious meddling.” Oklahoma Press , supra , at
213.

															D

															Today, however, the majority inexplicably
ignores the settled rule of Oklahoma Press in favor of a
resurrected version of Boyd . That is mystifying. This should
have been an easy case regardless of whether the Court looked to
the original understanding of the Fourth Amendment or to our modern
doctrine.

															As a matter of original understanding, the
Fourth Amendment does not regulate the compelled production of
documents at all. Here the Government received the relevant
cell-site records pursuant to a court order compelling Carpenter’s
cell service provider to turn them over. That process is thus
immune from challenge under the original understanding of the
Fourth Amendment.

															As a matter of modern doctrine, this case is
equally straightforward. As Justice Kennedy explains, no search or
seizure of Carpenter or his property occurred in this case. Ante , at 6–22; see also Part II, infra . But even if
the majority were right that the Government “searched” Carpenter,
it would at most be a “figurative or constructive search” governed
by the Oklahoma Press standard, not an “actual search”
controlled by the Fourth Amendment’s warrant requirement.

															And there is no doubt that the Government met
the Oklahoma Press standard here. Under Oklahoma
Press , a court order must “ ‘be sufficiently limited in
scope, relevant in purpose, and specific in directive so that
compliance will not be unreasonably burdensome.’ ” Lone
Steer, Inc. , supra , at 415. Here, the type of order
obtained by the Government almost necessarily satisfies that
standard. The Stored Communications Act allows a court to issue the
relevant type of order “only if the governmental entity offers
specific and articulable facts showing that there are reasonable
grounds to believe that . . . the records . . .
sough[t] are relevant and material to an ongoing criminal
investigation.” 18 U. S. C. §2703(d). And the court “may
quash or modify such order” if the provider objects that the
“records requested are unusually voluminous in nature or compliance
with such order otherwise would cause an undue burden on such
provider.” Ibid. No such objection was made in this case,
and Carpenter does not suggest that the orders contravened the Oklahoma Press standard in any other way.

															That is what makes the majority’s opinion so
puzzling. It decides that a “search” of Carpenter occurred within
the meaning of the Fourth Amendment, but then it leaps straight to
imposing requirements that—until this point—have governed only actual searches and seizures. See ante , at 18–19.
Lost in its race to the finish is any real recognition of the
century’s worth of precedent it jeopardizes. For the majority, this
case is apparently no different from one in which Government agents
raided Carpenter’s home and removed records associated with his
cell phone.

															Against centuries of precedent and practice, all
that the Court can muster is the observation that “this Court has
never held that the Government may subpoena third parties for
records in which the suspect has a reasonable expectation of
privacy.” Ante , at 19. Frankly, I cannot imagine a
concession more damning to the Court’s argument than that. As the
Court well knows, the reason that we have never seen such a case is
because—until today—defendants categorically had no “reasonable
expectation of privacy” and no property interest in records
belonging to third parties. See Part II, infra . By implying
otherwise, the Court tries the nice trick of seeking shelter under
the cover of precedents that it simultaneously perforates.

															Not only that, but even if the Fourth Amendment
permitted someone to object to the subpoena of a third party’s
records, the Court cannot explain why that individual should be
entitled to greater Fourth Amendment protection than the
party actually being subpoenaed. When parties are subpoenaed to
turn over their records, after all, they will at most receive the
protection afforded by Oklahoma Press even though they will
own and have a reasonable expectation of privacy in the records at
issue. Under the Court’s decision, however, the Fourth Amendment
will extend greater protections to someone else who is not being
subpoenaed and does not own the records. That outcome makes no
sense, and the Court does not even attempt to defend it.

															We have set forth the relevant Fourth Amendment
standard for subpoenaing business records many times over. Out of
those dozens of cases, the majority cannot find even one that so
much as suggests an exception to the Oklahoma Press standard
for sufficiently personal information. Instead, we have always
“described the constitutional requirements” for compulsory process
as being “ ‘settled’ ” and as applying categorically to
all “ ‘subpoenas [of] corporate books or records.’ ” Lone Steer, Inc. , 464 U. S., at 415 (internal quotation
marks omitted). That standard, we have held, is “ the most ”
protection the Fourth Amendment gives “to the production of
corporate records and papers.” Oklahoma Press , 327
U. S. , at 208 (emphasis added).[ 2 ]

															Although the majority announces its holding in
the context of the Stored Communications Act, nothing stops its
logic from sweeping much further. The Court has offered no
meaningful limiting principle, and none is apparent. Cf. Tr. of
Oral Arg. 31 (Carpenter’s counsel admitting that “a grand jury
subpoena . . . would be held to the same standard as any
other subpoena or subpoena-like request for [cell-site]
records”).

															Holding that subpoenas must meet the same
standard as conventional searches will seriously damage, if not
destroy, their utility. Even more so than at the founding, today
the Government regularly uses subpoenas duces tecum and
other forms of compulsory process to carry out its essential
functions. See, e.g. , Dionisio , 410 U. S., at
11–12 (grand jury subpoenas); McPhaul , 364 U. S., at
382–383 (legislative subpoenas); Oklahoma Press , supra , at 208–209 (administrative subpoenas). Grand juries,
for example, have long “compel[led] the production of evidence” in
order to determine “ whether there is probable cause to
believe a crime has been committed.” Calandra , 414
U. S., at 343 (emphasis added). Almost by definition, then,
grand juries will be unable at first to demonstrate “the probable
cause required for a warrant.” Ante , at 19 (majority
opinion); see also Oklahoma Press , supra , at 213. If
they are required to do so, the effects are as predictable as they
are alarming: Many investigations will sputter out at the start,
and a host of criminals will be able to evade law enforcement’s
reach.

															“To ensure that justice is done, it is
imperative to the function of courts that compulsory process be
available for the production of evidence.” Nixon , 418
U. S., at 709. For over a hundred years, we have understood
that holding subpoenas to the same standard as actual searches and
seizures “would stop much if not all of investigation in the public
interest at the threshold of inquiry.” Oklahoma Press , supra , at 213. Today a skeptical majority decides to put
that understanding to the test.

															II

															Compounding its initial error, the Court also
holds that a defendant has the right under the Fourth Amendment to
object to the search of a third party’s property. This holding
flouts the clear text of the Fourth Amendment, and it cannot be
defended under either a property-based interpretation of that
Amendment or our decisions applying the
reasonable-expectations-of-privacy test adopted in Katz , 389
U. S. 347. By allowing Carpenter to object to the search of a
third party’s property, the Court threatens to revolutionize a
second and independent line of Fourth Amendment doctrine.

															A

															It bears repeating that the Fourth Amendment
guarantees “[t]he right of the people to be secure in their persons, houses, papers, and effects.” (Emphasis added.) The Fourth
Amendment does not confer rights with respect to the persons,
houses, papers, and effects of others. Its language makes clear
that “ Fourth Amendment rights are personal,” Rakas v. Illinois , 439 U. S. 128, 140 (1978), and as a result,
this Court has long insisted that they “may not be asserted
vicariously,” id. , at 133. It follows that a “person who is
aggrieved . . . only through the introduction of damaging
evidence secured by a search of a third person’s premises or
property has not had any of his Fourth Amendment rights infringed.” Id. , at 134.

															In this case, as Justice Kennedy cogently
explains, the cell-site records obtained by the Government belong
to Carpenter’s cell service providers, not to Carpenter. See ante , at 12–13. Carpenter did not create the cell-site
records. Nor did he have possession of them; at all relevant times,
they were kept by the providers. Once Carpenter subscribed to his
provider’s service, he had no right to prevent the company from
creating or keeping the information in its records. Carpenter also
had no right to demand that the providers destroy the records, no
right to prevent the providers from destroying the records, and,
indeed, no right to modify the records in any way whatsoever (or to
prevent the providers from modifying the records). Carpenter, in
short, has no meaningful control over the cell-site records, which
are created, maintained, altered, used, and eventually destroyed by
his cell service providers.

															Carpenter responds by pointing to a provision of
the Telecommunications Act that requires a provider to disclose
cell-site records when a customer so requests. See 47
U. S. C. §222(c)(2). But a statutory disclosure
requirement is hardly sufficient to give someone an ownership
interest in the documents that must be copied and disclosed. Many
statutes confer a right to obtain copies of documents without
creating any property right.[ 3 ]

															Carpenter’s argument is particularly hard to
swallow because nothing in the Telecommunications Act precludes
cell service providers from charging customers a fee for accessing
cell-site records. See ante , at 12–13 (Kennedy, J.,
dissenting). It would be very strange if the owner of records were
required to pay in order to inspect his own property.

															Nor does the Telecommunications Act give
Carpenter a property right in the cell-site records simply because
they are subject to confidentiality restrictions. See 47
U. S. C. §222(c)(1) (without a customer’s permission, a
cell service provider may generally “use, disclose, or permit
access to individually identifiable [cell-site records]” only with
respect to “its provision” of telecommunications services). Many
federal statutes impose similar restrictions on private entities’
use or dissemination of information in their own records without
conferring a property right on third parties.[ 4 ]

															It would be especially strange to hold that the
Telecommunication Act’s confidentiality provision confers a
property right when the Act creates an express exception for any
disclosure of records that is “required by law.” 47
U. S. C. §222(c)(1). So not only does Carpenter lack
“ ‘the most essential and beneficial’ ” of the
“ ‘constituent elements’ ” of property, Dickman v. Commissioner , 465 U. S. 330, 336 (1984)— i.e. ,
the right to use the property to the exclusion of others—but he
cannot even exclude the party he would most like to keep out,
namely, the Government.[ 5 ]

															For all these reasons, there is no plausible
ground for maintaining that the information at issue here
represents Carpenter’s “papers” or “effects.”[ 6 ]

															B

															In the days when this Court followed an
exclusively property-based approach to the Fourth Amendment, the
distinction between an individual’s Fourth Amendment rights and
those of a third party was clear cut. We first asked whether the
object of the search—say, a house, papers, or effects—belonged to
the defendant, and, if it did, whether the Government had committed
a “trespass” in acquiring the evidence at issue. Jones , 565
U. S., at 411, n. 8.

															When the Court held in Katz that
“property rights are not the sole measure of Fourth Amendment
violations,” Soldal v. Cook County , 506 U. S.
56, 64 (1992), the sharp boundary between personal and third-party
rights was tested. Under Katz , a party may invoke the Fourth
Amendment whenever law enforcement officers violate the party’s
“justifiable” or “reasonable” expectation of privacy. See 389
U. S., at 353; see also id. , at 361 (Harlan, J.,
concurring) (applying the Fourth Amendment where “a person [has]
exhibited an actual (subjective) expectation of privacy” and where
that “expectation [is] one that society is prepared to recognize as
‘reasonable’ ”). Thus freed from the limitations imposed by
property law, parties began to argue that they had a reasonable
expectation of privacy in items owned by others. After all, if a
trusted third party took care not to disclose information about the
person in question, that person might well have a reasonable
expectation that the information would not be revealed.

															Efforts to claim Fourth Amendment protection
against searches of the papers and effects of others came to a head
in Miller , 425 U. S. 435, where the defendant sought
the suppression of two banks’ microfilm copies of his checks,
deposit slips, and other records. The defendant did not claim that
he owned these documents, but he nonetheless argued that “analysis
of ownership, property rights and possessory interests in the
determination of Fourth Amendment rights ha[d] been severely
impeached” by Katz and other recent cases. See Brief for
Respondent in United States v. Miller , O. T. 1975,
No. 74–1179, p. 6. Turning to Katz , he then argued that
he had a reasonable expectation of privacy in the banks’ records
regarding his accounts. Brief for Respondent in No. 74–1179, at 6;
see also Miller , supra , at 442–443.

															Acceptance of this argument would have flown in
the face of the Fourth Amendment’s text, and the Court rejected
that development. Because Miller gave up “dominion and control” of
the relevant information to his bank, Rakas, 439 U. S.,
at 149, the Court ruled that he lost any protected Fourth Amendment
interest in that information. See Miller , supra , at
442–443. Later, in Smith v. Maryland , 442 U. S.
735, 745 (1979), the Court reached a similar conclusion regarding a
telephone company’s records of a customer’s calls. As Justice
Kennedy concludes, Miller and Smith are thus best
understood as placing “necessary limits on the ability of
individuals to assert Fourth Amendment interests in property to
which they lack a ‘requisite connection.’ ” Ante , at
8.

															The same is true here, where Carpenter
indisputably lacks any meaningful property-based connection to the
cell-site records owned by his provider. Because the records are
not Carpenter’s in any sense, Carpenter may not seek to use the
Fourth Amendment to exclude them.

															By holding otherwise, the Court effectively
allows Carpenter to object to the “search” of a third party’s
property, not recognizing the revolutionary nature of this change.
The Court seems to think that Miller and Smith invented a new “doctrine”—“the third-party doctrine”—and the Court
refuses to “extend” this product of the 1970’s to a new age of
digital communications. Ante , at 11, 17. But the Court
fundamentally misunderstands the role of Miller and Smith . Those decisions did not forge a new doctrine;
instead, they rejected an argument that would have disregarded the
clear text of the Fourth Amendment and a formidable body of
precedent.

															In the end, the Court never explains how its
decision can be squared with the fact that the Fourth Amendment
protects only “[t]he right of the people to be secure in their persons, houses, papers, and effects.” (Emphasis
added.)

															*  *  *

															Although the majority professes a desire not
to “ ‘embarrass the future,’ ” ante , at 18, we can
guess where today’s decision will lead.

															One possibility is that the broad principles
that the Court seems to embrace will be applied across the board.
All subpoenas duces tecum and all other orders compelling
the production of documents will require a demonstration of
probable cause, and individuals will be able to claim a protected
Fourth Amendment interest in any sensitive personal information
about them that is collected and owned by third parties. Those
would be revolutionary developments indeed.

															The other possibility is that this Court will
face the embarrassment of explaining in case after case that the
principles on which today’s decision rests are subject to all sorts
of qualifications and limitations that have not yet been
discovered. If we take this latter course, we will inevitably end
up “mak[ing] a crazy quilt of the Fourth Amendment.” Smith , supra , at 745.

															All of this is unnecessary. In the Stored
Communications Act, Congress addressed the specific problem at
issue in this case. The Act restricts the misuse of cell-site
records by cell service providers, something that the Fourth
Amendment cannot do. The Act also goes beyond current Fourth
Amendment case law in restricting access by law enforcement. It
permits law enforcement officers to acquire cell-site records only
if they meet a heightened standard and obtain a court order. If the
American people now think that the Act is inadequate or needs
updating, they can turn to their elected representatives to adopt
more protective provisions. Because the collection and storage of
cell-site records affects nearly every American, it is unlikely
that the question whether the current law requires strengthening
will escape Congress’s notice.

															Legislation is much preferable to the
development of an entirely new body of Fourth Amendment caselaw for
many reasons, including the enormous complexity of the subject, the
need to respond to rapidly changing technology, and the Fourth
Amendment’s limited scope. The Fourth Amendment restricts the
conduct of the Federal Government and the States; it does not apply
to private actors. But today, some of the greatest threats to
individual privacy may come from powerful private companies that
collect and sometimes misuse vast quantities of data about the
lives of ordinary Americans. If today’s decision encourages the
public to think that this Court can protect them from this looming
threat to their privacy, the decision will mislead as well as
disrupt. And if holding a provision of the Stored Communications
Act to be unconstitutional dissuades Congress from further
legislation in this field, the goal of protecting privacy will be
greatly disserved.

															The desire to make a statement about privacy in
the digital age does not justify the consequences that today’s
decision is likely to produce. Notes 1 Any other interpretation
of the Fourth Amendment’s text would run into insuperable problems
because it would apply not only to subpoenas duces tecum but
to all other forms of compulsory process as well. If the Fourth
Amendment applies to the compelled production of documents, then it
must also apply to the compelled production of testimony—an outcome
that we have repeatedly rejected and which, if accepted, would send
much of the field of criminal procedure into a tailspin. See, e.g. , United States v. Dionisio , 410
U. S. 1, 9 (1973) (“It is clear that a subpoena to appear
before a grand jury is not a ‘seizure’ in the Fourth Amendment
sense, even though that summons may be inconvenient or
burdensome”); United States v. Calandra , 414
U. S. 338, 354 (1974) (“Grand jury questions . . .
involve no independent governmental invasion of one’s person,
house, papers, or effects”). As a matter of original understanding,
a subpoena duces tecum no more effects a “search” or
“seizure” of papers within the meaning of the Fourth Amendment than
a subpoena ad testificandum effects a “search” or “seizure”
of a person. 2 All that the Court can
say in response is that we have “been careful not to uncritically
extend existing precedents” when confronting new technologies. Ante , at 20. But applying a categorical rule categorically
does not “extend” precedent, so the Court’s statement ends up
sounding a lot like a tacit admission that it is overruling our
precedents. 3 See, e.g. , Freedom
of Information Act, 5 U. S. C. §552(a) (“Each agency
shall make available to the public information as follows
. . .”); Privacy Act, 5 U. S. C. §552a(d)(1)
(“Each agency that maintains a system of records shall
. . . upon request by any individual to gain access to
his record or to any information pertaining to him which is
contained in the system, permit him and upon his request, a person
of his own choosing to accompany him, to review the record and have
a copy made of all or any portion thereof . . .”); Fair
Credit Reporting Act, 15 U. S. C. §1681j(a)(1)(A) (“All
consumer reporting agencies . . . shall make all
disclosures pursuant to section 1681g of this title once during any
12-month period upon request of the consumer and without charge to
the consumer”); Right to Financial Privacy Act of 1978, 12
U. S. C. §3404(c) (“The customer has the right
. . . to obtain a copy of the record which the financial
institution shall keep of all instances in which the customer’s
record is disclosed to a Government authority pursuant to this
section, including the identity of the Government authority to
which such disclosure is made”); Government in the Sunshine Act, 5
U. S. C. §552b(f )(2) (“Copies of such transcript,
or minutes, or a transcription of such recording disclosing the
identity of each speaker, shall be furnished to any person at the
actual cost of duplication or transcription”); Cable Act, 47
U. S. C. §551(d) (“A cable subscriber shall be provided
access to all personally identifiable information regarding that
subscriber which is collected and maintained by a cable operator”);
Family Educational Rights and Privacy Act of 1974, 20
U. S. C. §1232g(a)(1)(A) (“No funds shall be made
available under any applicable program to any educational agency or
institution which has a policy of denying, or which effectively
prevents, the parents of students who are or have been in
attendance at a school of such agency or at such institution, as
the case may be, the right to inspect and review the education
records of their children. . . . Each educational
agency or institution shall establish appropriate procedures for
the granting of a request by parents for access to the education
records of their children within a reasonable period of time, but
in no case more than forty-five days after the request has been
made”). 4 See, e.g. , Family
Educational Rights and Privacy Act, 20 U. S. C.
§1232g(b)(1) (“No funds shall be made available under any
applicable program to any educational agency or institution which
has a policy or practice of permitting the release of education
records (or personally identifiable information contained therein
other than directory information . . . ) of students
without the written consent of their parents to any individual,
agency, or organization . . .”); Video Privacy Protection
Act, 18 U. S. C. §2710(b)(1) (“A video tape service
provider who knowingly discloses, to any person, personally
identifiable information concerning any consumer of such provider
shall be liable to the aggrieved person for the relief provided in
subsection (d)”); Driver Privacy Protection Act, 18
U. S. C. §2721(a)(1) (“A State department of motor
vehicles, and any officer, employee, or contractor thereof, shall
not knowingly disclose or otherwise make available to any person or
entity . . . personal information . . .”); Fair
Credit Reporting Act, 15 U. S. C. §1681b(a) (“[A]ny
consumer reporting agency may furnish a consumer report under the
following circumstances and no other . . .”); Right to
Financial Privacy Act, 12 U. S. C. §3403(a) (“No
financial institution, or officer, employees, or agent of a
financial institution, may provide to any Government authority
access to or copies of, or the information contained in, the
financial records of any customer except in accordance with the
provisions of this chapter”); Patient Safety and Quality
Improvement Act, 42 U. S. C. §299b–22(b)
(“Notwithstanding any other provision of Federal, State, or local
law, and subject to subsection (c) of this section, patient safety
work product shall be confidential and shall not be disclosed”);
Cable Act, 47 U. S. C. §551(c)(1) (“[A] cable operator
shall not disclose personally identifiable information concerning
any subscriber without the prior written or electronic consent of
the subscriber concerned and shall take such actions as are
necessary to prevent unauthorized access to such information by a
person other than the subscriber or cable operator”). 5 Carpenter also cannot
argue that he owns the cell-site records merely because they fall
into the category of records referred to as “customer proprietary
network information.” 47 U. S. C. §222(c). Even assuming
labels alone can confer property rights, nothing in this particular
label indicates whether the “information” is “proprietary” to the
“customer” or to the provider of the “network.” At best, the phrase
“customer proprietary network information” is ambiguous, and
context makes clear that it refers to the provider ’s
information. The Telecommunications Act defines the term to include
all “information that relates to the quantity, technical
configuration, type, destination, location, and amount of use of a
telecommunications service subscribed to by any customer of a
telecommunications carrier, and that is made available to the
carrier by the customer solely by virtue of the carrier-customer
relationship.” 47 U. S. C. §222(h)(1)(A). For Carpenter
to be right, he must own not only the cell-site records in this
case, but also records relating to, for example, the “technical
configuration” of his subscribed service—records that presumably
include such intensely personal and private information as
transmission wavelengths, transport protocols, and link layer
system configurations. 6 Thus, this is not a case
in which someone has entrusted papers that he or she owns to the
safekeeping of another, and it does not involve a bailment. Cf. post , at 14 (Gorsuch, J., dissenting). SUPREME COURT OF THE UNITED STATES

															_________________

															No. 16–402

															_________________

															TIMOTHY IVORY CARPENTER, PETITIONER v. UNITED STATES

															on writ of certiorari to the united states
court of appeals for the sixth circuit

															[June 22, 2018]

															Justice Gorsuch, dissenting.

															In the late 1960s this Court suggested for the
first time that a search triggering the Fourth Amendment occurs
when the government violates an “expectation of privacy” that
“society is prepared to recognize as ‘reasonable.’ ” Katz v. United States , 389 U. S. 347, 361 (1967)
(Harlan, J., concurring). Then, in a pair of decisions in the 1970s
applying the Katz test, the Court held that a “reasonable
expectation of privacy” doesn’t attach to information shared
with “third parties.” See Smith v. Maryland , 442
U. S. 735, 743–744 (1979); United States v. Miller , 425 U. S. 435, 443 (1976). By these steps, the
Court came to conclude, the Constitution does nothing to limit
investigators from searching records you’ve entrusted to your bank,
accountant, and maybe even your doctor.

															What’s left of the Fourth Amendment? Today we
use the Internet to do most everything. Smartphones make it easy to
keep a calendar, correspond with friends, make calls, conduct
banking, and even watch the game. Countless Internet companies
maintain records about us and, increasingly, for us. Even
our most private documents—those that, in other eras, we would have
locked safely in a desk drawer or destroyed—now reside on third
party servers. Smith and Miller teach that the police
can review all of this material, on the theory that no one
reasonably expects any of it will be kept private. But no one
believes that, if they ever did.

															What to do? It seems to me we could respond in
at least three ways. The first is to ignore the problem, maintain Smith and Miller , and live with the consequences. If
the confluence of these decisions and modern technology means our
Fourth Amendment rights are reduced to nearly nothing, so be it.
The second choice is to set Smith and Miller aside
and try again using the Katz “reasonable expectation of
privacy” jurisprudence that produced them. The third is to look for
answers elsewhere.

															*

															Start with the first option. Smith held
that the government’s use of a pen register to record the numbers
people dial on their phones doesn’t infringe a reasonable
expectation of privacy because that information is freely disclosed
to the third party phone company. 442 U. S., at 743–744. Miller held that a bank account holder enjoys no reason-
able expectation of privacy in the bank’s records of his account
activity. That’s true, the Court reasoned, “even if the information
is revealed on the assumption that it will be used only for a
limited purpose and the confidence placed in the third party will
not be betrayed.” 425 U. S., at 443. Today the Court suggests
that Smith and Miller distinguish between kinds of information disclosed to third parties and require
courts to decide whether to “extend” those decisions to particular
classes of information, depending on their sensitivity. See ante, at 10–18. But as the Sixth Circuit recognized and
Justice Kennedy explains, no balancing test of this kind can be
found in Smith and Miller . See ante , at 16
(dissenting opinion). Those cases announced a categorical rule:
Once you disclose information to third parties, you forfeit any
reason- able expectation of privacy you might have had in it. And
even if Smith and Miller did permit courts to conduct
a balancing contest of the kind the Court now suggests, it’s still
hard to see how that would help the petitioner in this case. Why is
someone’s location when using a phone so much more sensitive than
who he was talking to ( Smith ) or what financial transactions
he engaged in ( Miller )? I do not know and the Court does not
say.

															The problem isn’t with the Sixth Circuit’s
application of Smith and Miller but with the cases
themselves. Can the government demand a copy of all your e-mails
from Google or Microsoft without implicating your Fourth Amendment
rights? Can it secure your DNA from 23andMe without a warrant or
probable cause? Smith and Miller say yes it can—at
least without running afoul of Katz . But that result strikes
most lawyers and judges today—me in- cluded—as pretty unlikely. In
the years since its adoption, countless scholars, too, have come to
conclude that the “third-party doctrine is not only wrong, but
horribly wrong.” Kerr, The Case for the Third-Party Doctrine, 107
Mich. L. Rev. 561, 563, n. 5, 564 (2009) (collecting
criticisms but defending the doctrine (footnotes omitted)). The
reasons are obvious. “As an empirical statement about subjective
expectations of privacy,” the doctrine is “quite dubious.” Baude
& Stern, The Positive Law Model of the Fourth Amendment, 129
Harv. L. Rev. 1821, 1872 (2016). People often do reasonably expect that information they entrust to third parties,
especially information subject to confidentiality agreements, will
be kept private. Meanwhile, if the third party doctrine is supposed
to represent a normative assessment of when a person should expect
privacy, the notion that the answer might be “never” seems a pretty
unattractive societal prescription. Ibid. What, then, is the explanation for our third
party doctrine? The truth is, the Court has never offered a
persuasive justification. The Court has said that by conveying
information to a third party you “ ‘assum[e] the risk’ ”
it will be revealed to the police and therefore lack a reason- able
expectation of privacy in it. Smith , supra, at 744.
But assumption of risk doctrine developed in tort law. It generally
applies when “by contract or otherwise [one] expressly agrees to
accept a risk of harm” or impliedly does so by “manifest[ing] his
willingness to accept” that risk and thereby “take[s] his chances
as to harm which may result from it.” Restatement (Second) of Torts
§§496B, 496C(1), and Comment b (1965); see also 1 D. Dobbs,
P. Hayden, & E. Bublick, Law of Torts §§235–236, pp. 841–850
(2d ed. 2017). That rationale has little play in this context.
Suppose I entrust a friend with a letter and he promises to keep it
secret until he delivers it to an intended recipient. In what sense
have I agreed to bear the risk that he will turn around, break his
promise, and spill its contents to someone else? More confusing
still, what have I done to “manifest my willingness to accept” the
risk that the government will pry the document from my friend and
read it without his consent?

															One possible answer concerns knowledge. I know
that my friend might break his promise, or that the
government might have some reason to search the papers in
his possession. But knowing about a risk doesn’t mean you assume
responsibility for it. Whenever you walk down the sidewalk you know
a car may negligently or recklessly veer off and hit you, but that
hardly means you accept the consequences and absolve the driver of
any damage he may do to you. Epstein, Privacy and the Third Hand:
Lessons From the Common Law of Reasonable Expectations, 24 Berkeley
Tech. L. J. 1199, 1204 (2009); see W. Keeton, D. Dobbs, R.
Keeton, & D. Owen, Prosser & Keeton on Law of Torts 490
(5th ed. 1984).

															Some have suggested the third party doctrine is
better understood to rest on consent than assumption of risk. “So
long as a person knows that they are disclosing information to a
third party,” the argument goes, “their choice to do so is
voluntary and the consent valid.” Kerr, supra, at 588. I
confess I still don’t see it. Consenting to give a third party
access to private papers that remain my property is not the same
thing as consenting to a search of those papers by the
government. Perhaps there are exceptions, like when the third
party is an undercover government agent. See Murphy, The Case
Against the Case Against the Third-Party Doctrine: A Response to
Epstein and Kerr, 24 Berkeley Tech. L. J. 1239, 1252 (2009);
cf. Hoffa v. United States , 385 U. S. 293
(1966). But otherwise this conception of consent appears to be just
assumption of risk relabeled—you’ve “consented” to whatever risks
are foreseeable.

															Another justification sometimes offered for
third party doctrine is clarity. You (and the police) know exactly
how much protection you have in information confided to others:
none. As rules go, “the king always wins” is admi- rably clear. But
the opposite rule would be clear too: Third party disclosures never diminish Fourth Amendment protection (call it “the
king always loses”). So clarity alone cannot justify the third
party doctrine.

															In the end, what do Smith and Miller add up to? A doubtful application of Katz that
lets the government search almost whatever it wants whenever it
wants. The Sixth Circuit had to follow that rule and faithfully did
just that, but it’s not clear why we should.

															*

															There’s a second option. What if we dropped Smith and Miller ’s third party doctrine and retreated
to the root Katz question whether there is a “reasonable
expectation of privacy” in data held by third parties? Rather than
solve the problem with the third party doctrine, I worry this
option only risks returning us to its source: After all, it was Katz that produced Smith and Miller in the
first place. Katz’s problems start with the text and
original understanding of the Fourth Amendment, as Justice Thomas
thoughtfully explains today. Ante, at 5–17 (dissenting
opinion). The Amendment’s protections do not depend on the breach
of some abstract “expectation of privacy” whose contours are left
to the judicial imagination. Much more concretely, it protects your
“person,” and your “houses, papers, and effects.” Nor does your
right to bring a Fourth Amendment claim depend on whether a judge
happens to agree that your subjective expectation to privacy is a
“reasonable” one. Under its plain terms, the Amendment grants you
the right to invoke its guarantees whenever one of your protected
things (your person, your house, your papers, or your effects) is
unreasonably searched or seized. Period.

															History too holds problems for Katz .
Little like it can be found in the law that led to the adoption of
the Fourth Amendment or in this Court’s jurisprudence until the
late 1960s. The Fourth Amendment came about in response to a trio
of 18th century cases “well known to the men who wrote and ratified
the Bill of Rights, [and] famous throughout the colonial
population.” Stuntz, The Substantive Origins of Criminal Procedure,
105 Yale L. J. 393, 397 (1995). The first two were English
cases invalidating the Crown’s use of general warrants to enter
homes and search papers. Entick v. Carrington , 19
How. St. Tr. 1029 (K. B. 1765); Wilkes v. Wood ,
19 How. St. Tr. 1153 (K. B. 1763); see W. Cuddihy, The Fourth
Amendment: Origins and Original Meaning 439–487 (2009); Boyd v. United States , 116 U. S. 616, 625–630 (1886). The
third was American: the Boston Writs of Assistance Case, which
sparked colonial outrage at the use of writs permitting government
agents to enter houses and business, breaking open doors and chests
along the way, to conduct searches and seizures—and to force third
parties to help them. Stuntz, supra, at 404–409; M. Smith,
The Writs of Assistance Case (1978). No doubt the colonial outrage
engendered by these cases rested in part on the government’s
intrusion upon privacy. But the framers chose not to protect
privacy in some ethereal way dependent on judicial intuitions. They
chose instead to protect privacy in particular places and
things—“persons, houses, papers, and effects”—and against
particular threats—“unreasonable” governmental “searches and
seizures.” See Entick , supra, at 1066 (“Papers are
the owner’s goods and chattels; they are his dearest property; and
so far from enduring a seizure, that they will hardly bear an
inspection”); see also ante, at 1–21 (Thomas, J.,
dissenting).

															Even taken on its own terms, Katz has
never been sufficiently justified. In fact, we still don’t even
know what its “reasonable expectation of privacy” test is .
Is it supposed to pose an empirical question (what privacy
expectations do people actually have) or a normative one
(what expectations should they have)? Either way brings
problems. If the test is supposed to be an empirical one, it’s
unclear why judges rather than legislators should conduct it.
Legislators are responsive to their constituents and have
institutional resources designed to help them discern and enact
majoritarian preferences. Politically insulated judges come armed
with only the attorneys’ briefs, a few law clerks, and their own
idiosyncratic experiences. They are hardly the representative group
you’d expect (or want) to be making empirical judgments for
hundreds of millions of people. Unsurprisingly, too, judicial
judgments often fail to reflect public views. See Slobogin &
Schumacher, Reasonable Expectations of Privacy and Autonomy in
Fourth Amendment Cases: An Empirical Look at “Understandings
Recognized and Permitted by Society,” 42 Duke L. J. 727, 732,
740–742 (1993). Consider just one example. Our cases insist that
the seriousness of the offense being investigated does not reduce Fourth Amendment protection. Mincey v. Arizona , 437 U. S. 385, 393–394 (1978). Yet scholars
suggest that most people are more tolerant of police
intrusions when they investigate more serious crimes. See
Blumenthal, Adya, & Mogle, The Multiple Dimensions of Privacy:
Testing Lay “Expectations of Privacy,” 11 U. Pa. J. Const. L. 331,
352–353 (2009). And I very much doubt that this Court would be
willing to adjust its Katz cases to reflect these findings
even if it believed them.

															Maybe, then, the Katz test should be
conceived as a normative question. But if that’s the case, why
(again) do judges, rather than legislators, get to determine
whether society should be prepared to recognize an
expectation of privacy as legitimate? Deciding what privacy
interests should be recognized often calls for a pure policy
choice, many times between incommensurable goods—between the value
of privacy in a particular setting and society’s interest in
combating crime. Answering questions like that calls for the
exercise of raw political will belonging to legislatures, not the
legal judgment proper to courts. See The Federalist No. 78, p. 465
(C. Rossiter ed. 1961) (A. Hamilton). When judges abandon legal
judgment for political will we not only risk decisions where
“reasonable expectations of privacy” come to bear “an uncanny
resemblance to those expectations of privacy” shared by Members of
this Court. Minnesota v. Carter , 525 U. S. 83,
97 (1998) (Scalia, J., concurring). We also risk undermining public
confidence in the courts themselves.

															My concerns about Katz come with a
caveat. Sometimes , I accept, judges may be able to discern
and describe existing societal norms. See, e.g., Florida v. Jardines , 569 U. S. 1, 8 (2013)
(inferring a license to enter on private property from the
“ ‘habits of the country’ ” (quoting McKee v. Gratz , 260 U. S. 127, 136 (1922))); Sachs, Finding Law,
107 Cal. L. Rev. (forthcoming 2019), online at
https://ssrn.com/ abstract=3064443 (as last visited June 19, 2018).
That is particularly true when the judge looks to positive law
rather than intuition for guidance on social norms. See Byrd v. United States, 584 U. S. ___, ___–___ (2018) (slip
op., at 7–9) (“general property-based concept[s] guid[e] the
resolution of this case”). So there may be some occasions
where Katz is capable of principled application—though it
may simply wind up approximating the more traditional option I will
discuss in a moment. Sometimes it may also be possible to apply Katz by analogizing from precedent when the line between an
existing case and a new fact pattern is short and direct. But so
far this Court has declined to tie itself to any significant
restraints like these. See ante, at 5, n. 1 (“[W]hile
property rights are often informative, our cases by no means
suggest that such an interest is ‘fundamental’ or ‘dispositive’ in
determining which expectations of privacy are legitimate”).

															As a result, Katz has yielded an often
unpredictable—and sometimes unbelievable—jurisprudence. Smith and Miller are only two examples; there are
many others. Take Florida v. Riley , 488 U. S.
445 (1989), which says that a police helicopter hovering 400 feet
above a person’s property invades no reasonable expectation of
privacy. Try that one out on your neighbors. Or California v. Greenwood , 486 U. S. 35 (1988), which holds that a
person has no reasonable expectation of privacy in the garbage he
puts out for collection. In that case, the Court said that the
homeowners forfeited their privacy interests because “[i]t is
common knowledge that plastic garbage bags left on or at the side
of a public street are readily accessible to animals, children,
scavengers, snoops, and other members of the public.” Id. ,
at 40 (footnotes omitted). But the habits of raccoons don’t prove
much about the habits of the country. I doubt, too, that most
people spotting a neighbor rummaging through their garbage would
think they lacked reasonable grounds to confront the rummager.
Making the decision all the stranger, California state law
expressly protected a homeowner’s property rights in
discarded trash. Id. , at 43. Yet rather than defer to that
as evidence of the people’s habits and reasonable expectations of
privacy, the Court substituted its own curious judgment.

															Resorting to Katz in data privacy cases
threatens more of the same. Just consider. The Court today says
that judges should use Katz ’s reasonable expectation of
privacy test to decide what Fourth Amendment rights people have in
cell-site location information, explaining that “no single rubric
definitively resolves which expectations of privacy are entitled to
protection.” Ante, at 5. But then it offers a twist. Lower
courts should be sure to add two special principles to their Katz calculus: the need to avoid “arbitrary power” and the
importance of “plac[ing] obstacles in the way of a too permeating
police surveillance.” Ante, at 6 (internal quotation marks
omitted). While surely laudable, these principles don’t offer lower
courts much guidance. The Court does not tell us, for example, how
far to carry either principle or how to weigh them against the
legitimate needs of law enforcement. At what point does access to
electronic data amount to “arbitrary” authority? When does police
surveillance become “too permeating”? And what sort of “obstacles”
should judges “place” in law enforcement’s path when it does? We
simply do not know.

															The Court’s application of these principles
supplies little more direction. The Court declines to say whether
there is any sufficiently limited period of time “for which the
Government may obtain an individual’s historical [location
information] free from Fourth Amendment scrutiny.” Ante, at
11, n. 3; see ante, at 11–15. But then it tells us that
access to seven days’ worth of information does trigger
Fourth Amendment scrutiny—even though here the carrier “produced
only two days of records.” Ante, at 11, n. 3 . Why is
the relevant fact the seven days of information the government asked for instead of the two days of information the
government actually saw ? Why seven days instead of ten or
three or one? And in what possible sense did the government
“search” five days’ worth of location information it was never even
sent? We do not know.

															Later still, the Court adds that it can’t say
whether the Fourth Amendment is triggered when the government
collects “real-time CSLI or ‘tower dumps’ (a download of
information on all the devices that connected to a particular cell
site during a particular interval).” Ante, at 17–18. But
what distinguishes historical data from real-time data, or seven
days of a single person’s data from a download of everyone ’s
data over some indefinite period of time? Why isn’t a tower dump
the paradigmatic example of “too permeating police
surveillance” and a dangerous tool of “arbitrary” authority—the
touchstones of the majority’s modified Katz analysis? On
what possible basis could such mass data collection survive the
Court’s test while collecting a single person’s data does not? Here
again we are left to guess. At the same time, though, the Court
offers some firm assurances. It tells us its decision does not “call into question conventional surveillance techniques
and tools, such as security cameras.” Ibid. That, however,
just raises more questions for lower courts to sort out about what
techniques qualify as “conventional” and why those techniques would
be okay even if they lead to “permeating police
surveillance” or “arbitrary police power.”

															Nor is this the end of it. After finding a
reasonable expectation of privacy, the Court says there’s still
more work to do. Courts must determine whether to “extend” Smith and Miller to the circumstances before them. Ante, at 11, 15–17. So apparently Smith and Miller aren’t quite left for dead; they just no longer have
the clear reach they once did. How do we measure their new reach?
The Court says courts now must conduct a second Katz -like balancing inquiry, asking whether the fact of
disclosure to a third party outweighs privacy interests in the
“category of information” so disclosed. Ante, at 13, 15–16.
But how are lower courts supposed to weigh these radically
different interests? Or assign values to different categories of
information? All we know is that historical cell-site location
information (for seven days, anyway) escapes Smith and Miller ’s shorn grasp, while a lifetime of bank or phone
records does not. As to any other kind of information, lower courts
will have to stay tuned.

															In the end, our lower court colleagues are left
with two amorphous balancing tests, a series of weighty and
incommensurable principles to consider in them, and a few
illustrative examples that seem little more than the product of
judicial intuition. In the Court’s defense, though, we have arrived
at this strange place not because the Court has misunderstood Katz . Far from it. We have arrived here because this is
where Katz inevitably leads.

															*

															There is another way. From the founding until
the 1960s, the right to assert a Fourth Amendment claim didn’t
depend on your ability to appeal to a judge’s per- sonal
sensibilities about the “reasonableness” of your expectations or
privacy. It was tied to the law. Jardines , 569 U. S.,
at 11; United States v. Jones , 565 U. S. 400,
405 (2012). The Fourth Amendment protects “the right of the people
to be secure in their persons, houses, papers and effects, against
unreasonable searches and seizures.” True to those words and their
original understanding, the traditional approach asked if a house,
paper or effect was yours under law. No more was needed to
trigger the Fourth Amendment. Though now often lost in Katz ’s shadow, this traditional understanding persists. Katz only “supplements, rather than displaces the
traditional property-based understanding of the Fourth Amendment.” Byrd , 584 U. S., at ___ (slip op., at 7) (internal
quotation marks omitted); Jardines , supra, at 11
(same); Soldal v. Cook County , 506 U. S. 56, 64
(1992) ( Katz did not “snuf[f ] out the previously
recognized protection for property under the Fourth
Amendment”).

															Beyond its provenance in the text and original
understanding of the Amendment, this traditional approach comes
with other advantages. Judges are supposed to decide cases based on
“democratically legitimate sources of law”—like positive law or
analogies to items protected by the enacted Constitution—rather
than “their own biases or personal policy preferences.” Pettys,
Judicial Discretion in Constitutional Cases, 26 J. L. & Pol.
123, 127 (2011). A Fourth Amendment model based on positive legal
rights “carves out significant room for legislative participation
in the Fourth Amendment context,” too, by asking judges to consult
what the people’s representatives have to say about their rights.
Baude & Stern, 129 Harv. L. Rev., at 1852. Nor is this
approach hobbled by Smith and Miller , for those cases
are just limitations on Katz , addressing only the
question whether individuals have a reasonable expectation of
privacy in materials they share with third parties. Under this more
traditional approach, Fourth Amendment protections for your papers
and effects do not automatically disappear just because you share
them with third parties.

															Given the prominence Katz has claimed in
our doctrine, American courts are pretty rusty at applying the
traditional approach to the Fourth Amendment. We know that if a
house, paper, or effect is yours, you have a Fourth Amendment
interest in its protection. But what kind of legal interest is
sufficient to make something yours ? And what source of law
determines that? Current positive law? The common law at 1791,
extended by analogy to modern times? Both? See Byrd , supra , at ___–___ (slip op., at 1–2) (Thomas, J.,
concurring); cf. Re, The Positive Law Floor, 129 Harv. L. Rev.
Forum 313 (2016). Much work is needed to revitalize this area and
answer these questions. I do not begin to claim all the answers
today, but (unlike with Katz ) at least I have a pretty good
idea what the questions are . And it seems to me a few things
can be said. First , the fact that a third party has
access to or possession of your papers and effects does not
necessarily eliminate your interest in them. Ever hand a private
document to a friend to be returned? Toss your keys to a valet at a
restaurant? Ask your neighbor to look after your dog while you
travel? You would not expect the friend to share the document with
others; the valet to lend your car to his buddy; or the neighbor to
put Fido up for adoption. Entrusting your stuff to others is a bailment . A bailment is the “delivery of personal property
by one person (the bailor ) to another (the bailee )
who holds the property for a certain purpose.” Black’s Law
Dictionary 169 (10th ed. 2014); J. Story, Commentaries on the Law
of Bailments §2, p. 2 (1832) (“a bailment is a delivery of a
thing in trust for some special object or purpose, and upon a
contract, expressed or implied, to conform to the object or purpose
of the trust”). A bailee normally owes a legal duty to keep the
item safe, according to the terms of the parties’ contract if they
have one, and according to the “implication[s] from their conduct”
if they don’t. 8 C. J. S., Bailments §36, pp. 468–469
(2017). A bailee who uses the item in a different way than he’s
supposed to, or against the bailor’s instructions, is liable for
conversion. Id. , §43, at 481; see Goad v. Harris , 207 Ala. 357, 92 So. 546, (1922); Knight v. Seney , 290 Ill. 11, 17, 124 N. E. 813, 815–816 (1919); Baxter v. Woodward , 191 Mich. 379, 385, 158
N. W. 137, 139 (1916). This approach is quite different from Smith and Miller ’s (counter)-intuitive approach to
reasonable expectations of privacy; where those cases extinguish
Fourth Amendment interests once records are given to a third party,
property law may preserve them.

															Our Fourth Amendment jurisprudence already
reflects this truth. In Ex parte Jackson , 96 U. S. 727
(1878), this Court held that sealed letters placed in the mail are
“as fully guarded from examination and inspection, except as to
their outward form and weight, as if they were retained by the
parties forwarding them in their own domiciles.” Id., at
733. The reason, drawn from the Fourth Amendment’s text, was that
“[t]he constitutional guaranty of the right of the people to be
secure in their papers against unreasonable searches and seizures
extends to their papers , thus closed against inspection, wherever they may be .” Ibid. (emphasis added). It did
not matter that letters were bailed to a third party (the
government, no less). The sender enjoyed the same Fourth Amendment
protection as he does “when papers are subjected to search in one’s
own household.” Ibid. These ancient principles may help us address
modern data cases too. Just because you entrust your data—in some
cases, your modern-day papers and effects—to a third party may not
mean you lose any Fourth Amendment interest in its contents.
Whatever may be left of Smith and Miller , few doubt
that e-mail should be treated much like the traditional mail it has
largely supplanted—as a bailment in which the owner retains a vital
and protected legal interest. See ante, at 13 (Kennedy, J.,
dissenting) (noting that enhanced Fourth Amendment protection may
apply when the “modern-day equivalents of an individual’s own
‘papers’ or ‘effects’ . . . are held by a third party”
through “bailment”); ante, at 23, n. 6 (Alito, J.,
dissenting) (reserving the question whether Fourth Amendment
protection may apply in the case of “bailment” or when “someone has
entrusted papers he or she owns . . . to the safekeeping
of another”); United States v. Warshak , 631
F. 3d 266, 285–286 (CA6 2010) (relying on an analogy to Jackson to extend Fourth Amendment protection to e-mail held
by a third party service provider). Second , I doubt that complete ownership
or exclusive control of property is always a necessary condition to
the assertion of a Fourth Amendment right. Where houses are
concerned, for example, individuals can enjoy Fourth Amendment
protection without fee simple title. Both the text of the Amendment
and the common law rule support that conclusion. “People call a
house ‘their’ home when legal title is in the bank, when they rent
it, and even when they merely occupy it rent free.” Carter ,
525 U. S., at 95–96 (Scalia, J., concurring). That rule
derives from the common law. Oystead v. Shed , 13
Mass. 520, 523 (1816) (explaining, citing “[t]he very learned
judges, Foster , Hale , and Coke ,” that the law
“would be as much disturbed by a forcible entry to arrest a boarder
or a servant, who had acquired, by contract, express or implied, a
right to enter the house at all times, and to remain in it as long
as they please, as if the object were to arrest the master of the
house or his children”). That is why tenants and resident family
members—though they have no legal title—have standing to complain
about searches of the houses in which they live. Chapman v. United States , 365 U. S. 610, 616–617 (1961), Bumper v. North Carolina , 391 U. S. 543, 548, n.
11 (1968).

															Another point seems equally true: just because
you have to entrust a third party with your data doesn’t
necessarily mean you should lose all Fourth Amendment protections
in it. Not infrequently one person comes into possession of someone
else’s property without the owner’s consent. Think of the finder of
lost goods or the policeman who impounds a car. The law recognizes
that the goods and the car still belong to their true owners, for
“where a person comes into lawful possession of the personal
property of another, even though there is no formal agreement
between the property’s owner and its possessor, the possessor will
become a constructive bailee when justice so requires.” Christensen v. Hoover , 643 P.2d
525 , 529 (Colo. 1982) (en banc); Laidlaw, Principles of
Bailment, 16 Cornell L. Q. 286 (1931). At least some of this
Court’s decisions have already suggested that use of technology is
functionally compelled by the demands of modern life, and in that
way the fact that we store data with third parties may amount to a
sort of involuntary bailment too. See ante, at 12–13
(majority opinion); Riley v. California , 573
U. S. ___, ___ (2014) (slip op., at 9). Third , positive law may help provide
detailed guidance on evolving technologies without resort to
judicial intuition. State (or sometimes federal) law often creates
rights in both tangible and intangible things. See Ruckelshaus v. Monsanto Co. , 467 U. S. 986, 1001
(1984). In the context of the Takings Clause we often ask whether
those state-created rights are sufficient to make something
someone’s property for constitutional purposes. See id., at
1001–1003; Louisville Joint Stock Land Bank v. Radford , 295 U. S. 555, 590–595 (1935). A similar
inquiry may be appropriate for the Fourth Amendment. Both the
States and federal government are actively legislating in the area
of third party data storage and the rights users enjoy. See, e.g., Stored Communications Act, 18 U. S. C. §2701 et seq. ; Tex. Prop. Code Ann. §111.004(12) (West 2017)
(defining “[p]roperty” to include “property held in any digital or
electronic medium”). State courts are busy expounding common law
property principles in this area as well. E.g., Ajemian v. Yahoo!, Inc. , 478 Mass. 169, 170, 84 N. E. 3d 766, 768
(2017) (e-mail account is a “form of property often referred to as
a ‘digital asset’ ”); Eysoldt v. ProScan
Imaging , 194 Ohio App. 3d 630, 638, 2011–Ohio–2359, 957
N. E. 2d 780, 786 (2011) (permitting action for conversion of
web account as intangible property). If state legislators or state
courts say that a digital record has the attributes that normally
make something property, that may supply a sounder basis for
judicial decisionmaking than judicial guesswork about societal
expectations. Fourth , while positive law may help
establish a person’s Fourth Amendment interest there may be some
circumstances where positive law cannot be used to defeat it. Ex parte Jackson reflects that understanding. There
this Court said that “[n]o law of Congress” could authorize letter
carriers “to invade the secrecy of letters.” 96 U. S., at 733.
So the post office couldn’t impose a regulation dictating that
those mailing letters surrender all legal interests in them once
they’re deposited in a mailbox. If that is right, Jackson suggests the existence of a constitutional floor below which Fourth
Amendment rights may not descend. Legislatures cannot pass laws
declaring your house or papers to be your property except to the
extent the police wish to search them without cause. As the Court
has previously explained, “we must ‘assur[e] preservation of that
degree of privacy against government that existed when the Fourth
Amendment was adopted.’ ” Jones , 565 U. S., at 406
(quoting Kyllo v. United States , 533 U. S. 27,
34 (2001)). Nor does this mean protecting only the specific rights
known at the founding; it means protecting their modern analogues
too. So, for example, while thermal imaging was unknown in 1791,
this Court has recognized that using that technology to look inside
a home constitutes a Fourth Amendment “search” of that “home” no
less than a physical inspection might. Id., at 40. Fifth , this constitutional floor may, in
some instances, bar efforts to circumvent the Fourth Amendment’s
protection through the use of subpoenas. No one thinks the
government can evade Jackson ’s prohibition on opening sealed
letters without a warrant simply by issuing a subpoena to a
postmaster for “all letters sent by John Smith” or, worse, “all
letters sent by John Smith concerning a particular transaction.” So
the question courts will confront will be this: What other kinds of
records are sufficiently similar to letters in the mail that the
same rule should apply?

															It may be that, as an original matter, a
subpoena requiring the recipient to produce records wasn’t thought
of as a “search or seizure” by the government implicating the
Fourth Amendment, see ante, at 2–12 (opinion of Alito, J.),
but instead as an act of compelled self-incrimination implicating
the Fifth Amendment, see United States v. Hubbell ,
530 U. S. 27, 49–55 (2000) (Thomas, J., dissenting); Nagareda,
Compulsion “To Be a Witness” and the Resurrection of Boyd, 74
N. Y. U. L. Rev. 1575, 1619, and n. 172 (1999).
But the common law of searches and seizures does not appear to have
confronted a case where private documents equivalent to a mailed
letter were entrusted to a bailee and then subpoenaed. As a result,
“[t]he common-law rule regarding subpoenas for documents held by
third parties entrusted with information from the target is
. . . unknown and perhaps unknowable.” Dripps,
Perspectives on The Fourth Amendment Forty Years Later: Toward the
Realization of an Inclusive Regulatory Model, 100 Minn. L. Rev.
1885, 1922 (2016). Given that (perhaps insoluble) uncertainty, I am
content to adhere to Jackson and its implications for
now.

															To be sure, we must be wary of returning to the
doctrine of Boyd v. United States , 116 U. S.
616. Boyd invoked the Fourth Amendment to restrict the use
of subpoenas even for ordinary business records and, as Justice
Alito notes, eventually proved unworkable. See ante, at 13
(dissenting opinion); 3 W. LaFave, J. Israel, N. King, & O.
Kerr, Criminal Procedure §8.7(a), pp. 185–187 (4th ed. 2015). But
if we were to overthrow Jackson too and deny Fourth
Amendment protection to any subpoenaed materials, we would
do well to reconsider the scope of the Fifth Amendment while we’re
at it. Our precedents treat the right against self-incrimination as
applicable only to testimony, not the production of incriminating
evidence. See Fisher v. United States , 425 U. S.
391, 401 (1976). But there is substantial evidence that the
privilege against self-incrimination was also originally understood
to protect a person from being forced to turn over potentially
incriminating evidence. Nagareda, supra, at 1605–1623; Rex v. Purnell , 96 Eng. Rep. 20 (K. B. 1748);
Slobogin, Privacy at Risk 145 (2007).

															*

															What does all this mean for the case before
us? To start, I cannot fault the Sixth Circuit for holding that Smith and Miller extinguish any Katz -based
Fourth Amendment interest in third party cell-site data. That is
the plain effect of their categorical holdings. Nor can I fault the
Court today for its implicit but unmistakable conclusion that the
rationale of Smith and Miller is wrong; indeed, I
agree with that. The Sixth Circuit was powerless to say so, but
this Court can and should. At the same time, I do not agree with
the Court’s decision today to keep Smith and Miller on life support and supplement them with a new and multilayered
inquiry that seems to be only Katz -squared. Returning there,
I worry, promises more trouble than help. Instead, I would look to
a more traditional Fourth Amendment approach. Even if Katz may still supply one way to prove a Fourth Amendment interest, it
has never been the only way. Neglecting more traditional approaches
may mean failing to vindicate the full protections of the Fourth
Amendment.

															Our case offers a cautionary example. It seems
to me entirely possible a person’s cell-site data could qualify as his papers or effects under existing law. Yes, the telephone
carrier holds the information. But 47 U. S. C. §222
designates a customer’s cell-site location information as “customer
proprietary network information” (CPNI), §222(h)(1)(A), and gives
customers certain rights to control use of and access to CPNI about
themselves. The statute generally forbids a carrier to “use,
disclose, or permit access to individually identifiable” CPNI
without the customer’s consent, except as needed to provide the
customer’s telecommunications services. §222(c)(1). It also
requires the carrier to disclose CPNI “upon affirmative written
request by the customer, to any person designated by the customer.”
§222(c)(2). Congress even afforded customers a private cause of
action for damages against carriers who violate the Act’s terms.
§207. Plainly, customers have substantial legal interests in this
information, including at least some right to include, exclude, and
control its use. Those interests might even rise to the level of a
property right.

															The problem is that we do not know anything
more. Before the district court and court of appeals, Mr. Carpenter
pursued only a Katz “reasonable expectations” argument. He
did not invoke the law of property or any analogies to the common
law, either there or in his petition for certiorari. Even in his
merits brief before this Court, Mr. Carpenter’s discussion of his
positive law rights in cell-site data was cursory. He offered no
analysis, for example, of what rights state law might provide him
in addition to those supplied by §222. In these circumstances, I
cannot help but conclude—reluctantly—that Mr. Carpenter forfeited
perhaps his most promising line of argument.

															Unfortunately, too, this case marks the second
time this Term that individuals have forfeited Fourth Amendment
arguments based on positive law by failing to preserve them. See Byrd , 584 U. S., at ___ (slip op., at 7). Litigants
have had fair notice since at least United States v. Jones (2012) and Florida v. Jardines (2013)
that arguments like these may vindicate Fourth Amendment interests
even where Katz arguments do not. Yet the arguments have
gone unmade, leaving courts to the usual Katz hand- waving.
These omissions do not serve the development of a sound or fully
protective Fourth Amendment jurisprudence.