NOTICE: This opinion is subject to
formal revision before publication in the preliminary print of the
United States Reports. Readers are requested to notify the Reporter
of Decisions, Supreme Court of the United States, Washington,
D. C. 20543, of any typographical or other formal errors, in
order that corrections may be made before the preliminary print
goes to press.

															SUPREME COURT OF THE UNITED STATES

															_________________

															Nos. 13–132 and 13–212

															_________________

															DAVID LEON RILEY, PETITIONER

															13–132      v.

															CALIFORNIA

															on writ of certiorari to the court of appeal
of cali-fornia, fourth appellate district, division one

															UNITED STATES, PETITIONER

															13–212      v.

															BRIMA WURIE

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

															[June 25, 2014]

															     Chief Justice Roberts
delivered the opinion of the Court.

															     These two cases raise a
common question: whether the police may, without a warrant, search
digital information on a cell phone seized from an individual who
has been arrested.

															I

															A

															     In the first case,
petitioner David Riley was stopped by a police officer for driving
with expired registration tags. In the course of the stop, the
officer also learned that Riley’s license had been suspended. The
officer impounded Riley’s car, pursuant to department policy, and
another officer conducted an inventory search of the car. Riley was
arrested for possession of concealed and loaded firearms when that
search turned up two handguns under the car’s hood. See Cal. Penal
Code Ann. §§12025(a)(1), 12031(a)(1) (West 2009).

															     An officer searched
Riley incident to the arrest and found items associated with the
“Bloods” street gang. He also seized a cell phone from Riley’s
pants pocket. According to Riley’s uncontradicted assertion, the
phone was a “smart phone,” a cell phone with a broad range of other
functions based on advanced computing capability, large storage
capacity, and Internet connectivity. The officer accessed
information on the phone and noticed that some words (presumably in
text messages or a contacts list) were preceded by the letters
“CK”—a label that, he believed, stood for “Crip Killers,” a slang
term for members of the Bloods gang.

															     At the police station
about two hours after the arrest, a detective specializing in gangs
further examined the contents of the phone. The detective testified
that he “went through” Riley’s phone “looking for evidence, because
. . . gang members will often video themselves with guns
or take pictures of themselves with the guns.” App. in No. 13–132,
p. 20. Although there was “a lot of stuff” on the phone, particular
files that “caught [the detective’s] eye” included videos of young
men sparring while someone yelled encouragement using the moniker
“Blood.” Id., at 11–13. The police also found photographs of Riley
standing in front of a car they suspected had been involved in a
shooting a few weeks earlier.

															     Riley was ultimately
charged, in connection with that earlier shooting, with firing at
an occupied vehicle, assault with a semiautomatic firearm, and
attempted murder. The State alleged that Riley had committed those
crimes for the benefit of a criminal street gang, an aggravating
factor that carries an enhanced sentence. Compare Cal. Penal Code
Ann. §246 (2008) with §186.22(b)(4)(B) (2014). Prior to trial,
Riley moved to suppress all evidence that the police had obtained
from his cell phone. He contended that the searches of his phone
violated the Fourth Amendment, because they had been performed
without a warrant and were not otherwise justified by exigent
circumstances. The trial court rejected that argument. App. in No.
13–132, at 24, 26. At Riley’s trial, police officers testified
about the photographs and videos found on the phone, and some of
the photographs were admitted into evidence. Riley was convicted on
all three counts and received an enhanced sentence of 15 years to
life in prison.

															     The California Court of
Appeal affirmed. No. D059840 (Cal. App., Feb. 8, 2013), App. to
Pet. for Cert. in No. 13–132, pp. 1a–23a. The court relied on the
California Supreme Court’s decision in People v. Diaz, 51 Cal. 4th
84, 244 P. 3d 501 (2011), which held that the Fourth Amendment
permits a warrantless search of cell phone data incident to an
arrest, so long as the cell phone was immediately associated with
the arrestee’s person. See id., at 93, 244 P. 3d, at 505–506.

															     The California Supreme
Court denied Riley’s petition for review, App. to Pet. for Cert. in
No. 13–132, at 24a, and we granted certiorari, 571 U. S. ___
(2014).

															B

															     In the second case, a
police officer performing routine surveillance observed respondent
Brima Wurie make an apparent drug sale from a car. Officers
subsequently arrested Wurie and took him to the police station. At
the station, the officers seized two cell phones from Wurie’s
person. The one at issue here was a “flip phone,” a kind of phone
that is flipped open for use and that generally has a smaller range
of features than a smart phone. Five to ten minutes after arriving
at the station, the officers noticed that the phone was repeatedly
receiving calls from a source identified as “my house” on the
phone’s external screen. A few minutes later, they opened the phone
and saw a photograph of a woman and a baby set as the phone’s
wallpaper. They pressed one button on the phone to access its call
log, then another button to determine the phone number associated
with the “my house” label. They next used an online phone directory
to trace that phone number to an apartment building.

															     When the officers went
to the building, they saw Wurie’s name on a mailbox and observed
through a window a woman who resembled the woman in the photograph
on Wurie’s phone. They secured the apartment while obtaining a
search warrant and, upon later executing the warrant, found and
seized 215 grams of crack cocaine, mari-juana, drug paraphernalia,
a firearm and ammunition, and cash.

															     Wurie was charged with
distributing crack cocaine, possessing crack cocaine with intent to
distribute, and being a felon in possession of a firearm and
ammunition. See 18 U. S. C. §922(g); 21
U. S. C. §841(a). He moved to suppress the evidence
obtained from the search of the apartment, arguing that it was the
fruit of an unconstitutional search of his cell phone. The District
Court denied the motion. 612 F. Supp. 2d 104 (Mass. 2009).
Wurie was convicted on all three counts and sentenced to 262 months
in prison.

															     A divided panel of the
First Circuit reversed the denial of Wurie’s motion to suppress and
vacated Wurie’s convictions for possession with intent to
distribute and possession of a firearm as a felon. 728 F. 3d 1
(2013). The court held that cell phones are distinct from other
physical possessions that may be searched incident to arrest
without a warrant, because of the amount of personal data cell
phones contain and the negligible threat they pose to law
enforcement interests. See id., at 8–11.

															     We granted certiorari.
571 U. S. ___ (2014).

															II

															     The Fourth Amendment
provides:

															     “The right of the
people to be secure in their persons, houses, papers, and effects,
against unreasonable searches and seizures, shall not be violated,
and no Warrants shall issue, but upon probable cause, supported by
Oath or affirmation, and particularly describing the place to be
searched, and the persons or things to be seized.”

															     As the text makes
clear, “the ultimate touchstone of the Fourth Amendment is
‘reasonableness.’ ” Brigham City v. Stuart, 547 U. S.
398, 403 (2006) . Our cases have determined that “[w]here a search
is undertaken by law enforcement officials to discover evidence of
criminal wrongdoing, . . . reasonableness generally
requires the obtaining of a judicial warrant.” Vernonia School
Dist. 47J v. Acton, 515 U. S. 646, 653 (1995) . Such a warrant
ensures that the inferences to support a search are “drawn by a
neutral and detached magistrate instead of being judged by the
officer engaged in the often competitive enterprise of ferreting
out crime.” Johnson v. United States, 333 U. S. 10, 14 (1948)
. In the absence of a warrant, a search is reasonable only if it
falls within a specific exception to the warrant requirement. See
Kentucky v. King, 563 U. S. ___, ___ (2011) (slip op., at
5–6).

															     The two cases before us
concern the reasonableness of a warrantless search incident to a
lawful arrest. In 1914, this Court first acknowledged in dictum
“the right on the part of the Government, always recognized under
English and American law, to search the person of the accused when
legally arrested to discover and seize the fruits or evidences of
crime.” Weeks v. United States, 232 U. S. 383 . Since that
time, it has been well accepted that such a search constitutes an
exception to the warrant requirement. Indeed, the label “exception”
is something of a misnomer in this context, as warrantless searches
incident to arrest occur with far greater frequency than searches
conducted pursuant to a warrant. See 3 W. LaFave, Search and
Seizure §5.2(b), p. 132, and n. 15 (5th ed. 2012).

															     Although the existence
of the exception for such searches has been recognized for a
century, its scope has been de-bated for nearly as long. See
Arizona v. Gant, 556 U. S. 332, 350 (2009) (noting the
exception’s “checkered his-tory”). That debate has focused on the
extent to which officers may search property found on or near the
arrestee. Three related precedents set forth the rules governing
such searches:

															     The first, Chimel v.
California, 395 U. S. 752 (1969) , laid the groundwork for
most of the existing search incident to arrest doctrine. Police
officers in that case arrested Chimel inside his home and proceeded
to search his entire three-bedroom house, including the attic and
garage. In particular rooms, they also looked through the contents
of drawers. Id., at 753–754.

															     The Court crafted the
following rule for assessing the reasonableness of a search
incident to arrest:

															“When an arrest is made, it is reasonable
for the arresting officer to search the person arrested in order to
remove any weapons that the latter might seek to use in order to
resist arrest or effect his escape. Otherwise, the officer’s safety
might well be endangered, and the arrest itself frustrated. In
addition, it is entirely reasonable for the arresting officer to
search for and seize any evidence on the arrestee’s person in order
to prevent its concealment or destruction. . . .
There is ample justification, therefore, for a search of the
arrestee’s person and the area ‘within his immediate
control’—construing that phrase to mean the area from within which
he might gain possession of a weapon or destructible evidence.”
Id., at 762–763.

															The extensive warrantless search of Chimel’s
home did not fit within this exception, because it was not needed
to protect officer safety or to preserve evidence. Id., at 763,
768.

															     Four years later, in
United States v. Robinson, 414 U. S. 218 (1973) , the Court
applied the Chimel analysis in the context of a search of the
arrestee’s person. A police officer had arrested Robinson for
driving with a revoked license. The officer conducted a patdown
search and felt an object that he could not identify in Robinson’s
coat pocket. He removed the object, which turned out to be a
crumpled cigarette package, and opened it. Inside were 14 capsules
of heroin. Id., at 220, 223.

															     The Court of Appeals
concluded that the search was unreasonable because Robinson was
unlikely to have evidence of the crime of arrest on his person, and
because it believed that extracting the cigarette package and
opening it could not be justified as part of a protective search
for weapons. This Court reversed, rejecting the notion that
“case-by-case adjudication” was required to determine “whether or
not there was present one of the reasons supporting the authority
for a search of the person incident to a lawful arrest.” Id., at
235. As the Court explained, “[t]he authority to search the person
incident to a lawful custodial arrest, while based upon the need to
disarm and to discover evidence, does not depend on what a court
may later decide was the probability in a particular arrest
situation that weapons or evidence would in fact be found upon the
person of the suspect.” Ibid. Instead, a “custodial arrest of a
suspect based on probable cause is a reasonable intrusion under the
Fourth Amendment; that intrusion being lawful, a search incident to
the arrest requires no additional justification.” Ibid.

															     The Court thus
concluded that the search of Robinson was reasonable even though
there was no concern about the loss of evidence, and the arresting
officer had no specific concern that Robinson might be armed. Id.,
at 236. In doing so, the Court did not draw a line between a search
of Robinson’s person and a further examination of the cigarette
pack found during that search. It merely noted that, “[h]aving in
the course of a lawful search come upon the crumpled package of
cigarettes, [the officer] was entitled to inspect it.” Ibid. A few
years later, the Court clarified that this exception was limited to
“personal property . . . immediately associated with the
person of the arrestee.” United States v. Chadwick, 433 U. S. 1, 15
(1977) (200-pound, locked footlocker could not be searched incident
to arrest), abrogated on other grounds by California v. Acevedo,
500 U. S. 565 (1991) .

															     The search incident to
arrest trilogy concludes with Gant, which analyzed searches of an
arrestee’s vehicle. Gant, like Robinson, recognized that the Chimel
concerns for officer safety and evidence preservation underlie the
search incident to arrest exception. See 556 U. S., at 338. As
a result, the Court concluded that Chimel could authorize police to
search a vehicle “only when the arrestee is unsecured and within
reaching distance of the passenger compartment at the time of the
search.” 556 U. S., at 343. Gant added, however, an
independent exception for a warrantless search of a vehicle’s
passenger compartment “when it is ‘reasonable to believe evidence
relevant to the crime of arrest might be found in the
vehicle.’ ” Ibid. (quoting Thornton v. United States, 541
U. S. 615, 632 (2004) (Scalia, J., concurring in judgment)).
That exception stems not from Chimel, the Court explained, but from
“circumstances unique to the vehicle context.” 556 U. S., at
343.

															III

															     These cases require
us to decide how the search incident to arrest doctrine applies to
modern cell phones, which are now such a pervasive and insistent
part of daily life that the proverbial visitor from Mars might
conclude they were an important feature of human anatomy. A smart
phone of the sort taken from Riley was unheard of ten years ago; a
significant majority of American adults now own such phones. See A.
Smith, Pew Research Center, Smartphone Ownership—2013 Update (June
5, 2013). Even less sophisticated phones like Wurie’s, which have
already faded in popularity since Wurie was arrested in 2007, have
been around for less than 15 years. Both phones are based on
technology nearly inconceivable just a few decades ago, when Chimel
and Robinson were decided.

															     Absent more precise
guidance from the founding era, we generally determine whether to
exempt a given type of search from the warrant requirement “by
assessing, on the one hand, the degree to which it intrudes upon an
individual’s privacy and, on the other, the degree to which it is
needed for the promotion of legitimate governmental interests.”
Wyoming v. Houghton, 526 U. S. 295, 300 (1999) . Such a
balancing of interests supported the search incident to arrest
exception in Robinson, and a mechanical application of Robinson
might well support the warrantless searches at issue here.

															     But while Robinson’s
categorical rule strikes the appropriate balance in the context of
physical objects, neither of its rationales has much force with
respect to digital content on cell phones. On the government
interest side, Robinson concluded that the two risks identified in
Chimel—harm to officers and destruction of evidence—are present in
all custodial arrests. There are no comparable risks when the
search is of digital data. In addition, Robinson regarded any
privacy interests retained by an individual after arrest as
significantly diminished by the fact of the arrest itself. Cell
phones, however, place vast quantities of personal information
literally in the hands of individuals. A search of the information
on a cell phone bears little resemblance to the type of brief
physical search considered in Robinson.

															     We therefore decline to
extend Robinson to searches of data on cell phones, and hold
instead that officers must generally secure a warrant before
conducting such a search.

															A

															     We first consider
each Chimel concern in turn. In doing so, we do not overlook
Robinson’s admonition that searches of a person incident to arrest,
“while based upon theneed to disarm and to discover evidence,” are
reasonable regardless of “the probability in a particular arrest
situation that weapons or evidence would in fact be found.” 414 U.
S., at 235. Rather than requiring the “case-by-case adjudication”
that Robinson rejected, ibid., we ask instead whether application
of the search incident to arrest doctrine to this particular
category of effects would “untether the rule from the
justifications underlying the Chimel exception,” Gant, supra, at
343. See also Knowles v. Iowa, 525 U. S. 113, 119 (1998)
(declining to extend Robinson to the issuance of citations, “a
situation where the concern for officer safety is not present to
the same extent and the concern for destruction or loss of evidence
is not present at all”).

															1

															     Digital data stored
on a cell phone cannot itself be used as a weapon to harm an
arresting officer or to effectuate the arrestee’s escape. Law
enforcement officers remain free to examine the physical aspects of
a phone to ensure that it will not be used as a weapon—say, to
determine whether there is a razor blade hidden between the phone
and its case. Once an officer has secured a phone and eliminated
any potential physical threats, however, data on the phone can
endanger no one.

															     Perhaps the same might
have been said of the cigarette pack seized from Robinson’s pocket.
Once an officer gained control of the pack, it was unlikely that
Robinson could have accessed the pack’s contents. But unknown
physical objects may always pose risks, no matter how slight,
during the tense atmosphere of a custodial arrest. The officer in
Robinson testified that he could not identify the objects in the
cigarette pack but knew they were not cigarettes. See 414
U. S., at 223, 236, n. 7. Given that, a further search was a
reasonable protective measure. No such unknowns exist with respect
to digital data. As the First Circuit explained, the officers who
searched Wurie’s cell phone “knew exactly what they would find
therein: data. They also knew that the data could not harm them.”
728 F. 3d, at 10.

															     The United States and
California both suggest that a search of cell phone data might help
ensure officer safety in more indirect ways, for example by
alerting officers that confederates of the arrestee are headed to
the scene. There is undoubtedly a strong government interest in
warning officers about such possibilities, but neither the United
States nor California offers evidence to suggest that their
concerns are based on actual experience. The proposed consideration
would also represent a broadening of Chimel’s concern that an
arrestee himself might grab a weapon and use it against an officer
“to resist arrest or effect his escape.” 395 U. S., at 763.
And any such threats from outside the arrest scene do not “lurk[ ]
in all custodial arrests.” Chadwick, 433 U. S., at 14–15.
Accordingly, the interest in protecting officer safety does not
justify dispensing with the warrant requirement across the board.
To the extent dangers to arresting officers may be implicated in a
particular way in a particular case, they are better addressed
through consideration of case-specific exceptions to the warrant
requirement, such as the one for exigent circumstances. See, e.g.,
Warden, Md. Penitentiary v. Hayden, 387 U. S. 294 –299 (1967)
(“The Fourth Amendment does not require police officers to delay in
the course of an investigation if to do so would gravely endanger
their lives or the lives of others.”).

															2

															     The United States and
California focus primarily on the second Chimel rationale:
preventing the destruction of evidence.

															     Both Riley and Wurie
concede that officers could have seized and secured their cell
phones to prevent destruction of evidence while seeking a warrant.
See Brief for Petitioner in No. 13–132, p. 20; Brief for Respondent
in No. 13–212, p. 41. That is a sensible concession. See Illinois
v. McArthur, 531 U. S. 326 –333 (2001); Chadwick, supra, at
13, and n. 8. And once law enforcement officers have secured a cell
phone, there is no longer any risk that the arrestee himself will
be able to delete incriminating data from the phone.

															     The United States and
California argue that information on a cell phone may nevertheless
be vulnerable to two types of evidence destruction unique to
digital data—remote wiping and data encryption. Remote wiping
occurs when a phone, connected to a wireless network, receives a
signal that erases stored data. This can happen when a third party
sends a remote signal or when a phone is preprogrammed to delete
data upon entering or leaving certain geographic areas (so-called
“geofencing”). See Dept. of Commerce, National Institute of
Standards and Technology, R. Ayers, S. Brothers, & W. Jansen,
Guidelines on Mobile Device Forensics (Draft) 29, 31 (SP 800–101
Rev. 1, Sept. 2013) (hereinafter Ayers). Encryption is a security
feature that some modern cell phones use in addition to password
protection. When such phones lock, data becomes protected by
sophisticated encryption that renders a phone all but “unbreakable”
unless police know the password. Brief for United States as Amicus
Curiae in No. 13–132, p. 11.

															     As an initial matter,
these broader concerns about the loss of evidence are distinct from
Chimel’s focus on a defendant who responds to arrest by trying to
conceal or destroy evidence within his reach. See 395 U. S.,
at 763–764. With respect to remote wiping, the Government’s primary
concern turns on the actions of third parties who are not present
at the scene of arrest. And data encryption is even further afield.
There, the Government focuses on the ordinary operation of a
phone’s security features, apart from any active attempt by a
defendant or his associates to conceal or destroy evidence upon
arrest.

															     We have also been given
little reason to believe that either problem is prevalent. The
briefing reveals only a couple of anecdotal examples of remote
wiping triggered by an arrest. See Brief for Association of State
Criminal Investigative Agencies et al. as Amici Curiae in No.
13–132, pp. 9–10; see also Tr. of Oral Arg. in No. 13–132,p. 48.
Similarly, the opportunities for officers to search a
password-protected phone before data becomes encrypted are quite
limited. Law enforcement officers are very unlikely to come upon
such a phone in an unlocked state because most phones lock at the
touch of a button or, as a default, after some very short period of
inactivity. See, e.g., iPhone User Guide for iOS 7.1 Software 10
(2014) (default lock after about one minute). This may explain why
the encryption argument was not made until the merits stage in this
Court, and has never been considered by the Courts of Appeals.

															     Moreover, in situations
in which an arrest might trigger a remote-wipe attempt or an
officer discovers an unlocked phone, it is not clear that the
ability to conduct a warrantless search would make much of a
difference. The need to effect the arrest, secure the scene, and
tend to other press-ing matters means that law enforcement officers
may well not be able to turn their attention to a cell phone right
away. See Tr. of Oral Arg. in No. 13–132, at 50; see also Brief for
United States as Amicus Curiae in No. 13–132, at 19. Cell phone
data would be vulnerable to remote wiping from the time an
individual anticipates arrest to the time any eventual search of
the phone is completed, which might be at the station house hours
later. Likewise, an officer who seizes a phone in an unlocked state
might not be able to begin his search in the short time remaining
before the phone locks and data becomes encrypted.

															     In any event, as to
remote wiping, law enforcement is not without specific means to
address the threat. Remote wiping can be fully prevented by
disconnecting a phone from the network. There are at least two
simple ways to do this: First, law enforcement officers can turn
the phone off or remove its battery. Second, if they are concerned
about encryption or other potential problems, they can leave a
phone powered on and place it in an enclosure that isolates the
phone from radio waves. See Ayers 30–31. Such devices are commonly
called “Faraday bags,” after the English scientist Michael Faraday.
They are essentially sandwich bags made of aluminum foil: cheap,
lightweight, and easy to use. See Brief for Criminal Law Professors
as Amici Curiae 9. They may not be a complete answer to the
problem, see Ayers 32, but at least for now they provide a
reasonable response. In fact, a number of law enforcement agencies
around the country already encourage the use of Faraday bags. See,
e.g., Dept. of Justice, National Institute of Justice, Electronic
Crime Scene Investigation: A Guide for First Responders 14, 32 (2d
ed. Apr. 2008); Brief for Criminal Law Professors as Amici Curiae
4–6.

															     To the extent that law
enforcement still has specific concerns about the potential loss of
evidence in a particular case, there remain more targeted ways to
address those concerns. If “the police are truly confronted with a
‘now or never’ situation,”—for example, circumstances suggesting
that a defendant’s phone will be the target of an imminent
remote-wipe attempt—they may be able to rely on exigent
circumstances to search the phone immediately. Missouri v. McNeely,
569 U. S. ___, ___ (2013) (slip op., at 10) (quoting Roaden v.
Kentucky, 413 U. S. 496, 505 (1973) ; some internal quotation
marks omitted). Or, if officers happen to seize a phone in an
unlocked state, they may be able to disable a phone’s
automatic-lock feature in order to prevent the phone from locking
and encrypting data. See App. to Reply Brief in No. 13–132, p. 3a
(diagramming the few necessary steps). Such a preventive measure
could be analyzed under the principles set forth in our decision in
McArthur, 531 U. S. 326 , which approved officers’ reasonable
steps to secure a scene to preserve evidence while they awaited a
warrant. See id., at 331–333.

															B

															     The search incident
to arrest exception rests not only on the heightened government
interests at stake in a volatile arrest situation, but also on an
arrestee’s reduced privacy interests upon being taken into police
custody. Robinson focused primarily on the first of those
rationales. But it also quoted with approval then-Judge Cardozo’s
account of the historical basis for the search incident to arrest
exception: “Search of the person becomes lawful when grounds for
arrest and accusation have been discovered, and the law is in the
act of subjecting the body of the accused to its physical
dominion.” 414 U. S., at 232 (quoting People v. Chiagles, 237
N. Y. 193, 197, 142 N. E. 583, 584 (1923)); see also 414
U. S., at 237 (Powell, J., concurring) (“an individual
lawfully subjected to a custodial arrest retains no significant
Fourth Amendment interest in the privacy of his person”). Put
simply, a patdown of Robinson’s cloth-ing and an inspection of the
cigarette pack found in his pocket constituted only minor
additional intrusions compared to the substantial government
authority exercised in taking Robinson into custody. See Chadwick,
433 U. S., at 16, n. 10 (searches of a person are
justified in part by “reduced expectations of privacy caused by the
arrest”).

															     The fact that an
arrestee has diminished privacy interests does not mean that the
Fourth Amendment falls out of the picture entirely. Not every
search “is acceptable solely because a person is in custody.”
Maryland v. King, 569 U. S. ___, ___ (2013) (slip op., at 26).
To the contrary, when “privacy-related concerns are weighty enough”
a “search may require a warrant, notwithstanding the diminished
expectations of privacy of the arrestee.” Ibid. One such example,
of course, is Chimel. Chimel refused to “characteriz[e] the
invasion of privacy that results from a top-to-bottom search of a
man’s house as ‘minor.’ ” 395 U. S., at 766–767, n. 12.
Because a search of the arrestee’s entire house was a substantial
invasion beyond the arrest itself, the Court concluded that a
warrant was required.

															     Robinson is the only
decision from this Court applying Chimel to a search of the
contents of an item found on an arrestee’s person. In an earlier
case, this Court had approved a search of a zipper bag carried by
an arrestee, but the Court analyzed only the validity of the arrest
itself. See Draper v. United States, 358 U. S. 307 –311
(1959). Lower courts applying Robinson and Chimel, however, have
approved searches of a variety of personal items carried by an
arrestee. See, e.g., United States v. Carrion, 809 F. 2d 1120,
1123, 1128 (CA5 1987) (billfold and address book); United States v.
Watson, 669 F. 2d 1374, 1383–1384 (CA11 1982) (wallet); United
States v. Lee, 501 F. 2d 890, 892 (CADC 1974) (purse).

															     The United States
asserts that a search of all data stored on a cell phone is
“materially indistinguishable” from searches of these sorts of
physical items. Brief for United States in No. 13–212, p. 26. That
is like saying a ride on horseback is materially indistinguishable
from a flight to the moon. Both are ways of getting from point A to
point B, but little else justifies lumping them together. Modern
cell phones, as a category, implicate privacy concerns far beyond
those implicated by the search of a cigarette pack, a wallet, or a
purse. A conclusion that inspecting the contents of an arrestee’s
pockets works no substantial additional intrusion on privacy beyond
the arrest itself may make sense as applied to physical items, but
any extension of that reasoning to digital data has to rest on its
own bottom.

															1

															     Cell phones differ in
both a quantitative and a qualitative sense from other objects that
might be kept on an arrestee’s person. The term “cell phone” is
itself misleading shorthand; many of these devices are in fact
minicomputers that also happen to have the capacity to be used as a
telephone. They could just as easily be called cameras, video
players, rolodexes, calendars, tape recorders, libraries, diaries,
albums, televisions, maps, or newspapers.

															     One of the most notable
distinguishing features of modern cell phones is their immense
storage capacity. Before cell phones, a search of a person was
limited by physical realities and tended as a general matter to
constitute only a narrow intrusion on privacy. See Kerr, Foreword:
Accounting for Technological Change, 36 Harv. J. L. & Pub.
Pol’y 403, 404–405 (2013). Most people cannot lug around every
piece of mail they have received for the past several months, every
picture they have taken, or every book or article they have
read—nor would they have any reason to attempt to do so. And if
they did, they would have to drag behind them a trunk of the sort
held to require a search warrant in Chadwick, supra, rather than a
container the size of the cigarette package in Robinson.

															     But the possible
intrusion on privacy is not physically limited in the same way when
it comes to cell phones. The current top-selling smart phone has a
standard capacity of 16 gigabytes (and is available with up to 64
gigabytes). Sixteen gigabytes translates to millions of pages of
text, thousands of pictures, or hundreds of videos. See Kerr,
supra, at 404; Brief for Center for Democracy & Technol-ogy
et al. as Amici Curiae 7–8. Cell phones couple that capacity
with the ability to store many different types of information: Even
the most basic phones that sell for less than $20 might hold
photographs, picture messages, text messages, Internet browsing
history, a calendar, a thousand-entry phone book, and so on. See
id., at 30; United States v. Flores-Lopez, 670 F. 3d 803, 806
(CA7 2012). We expect that the gulf between physical practicability
and digital capacity will only continue to widen in the future.

															     The storage capacity of
cell phones has several interrelated consequences for privacy.
First, a cell phone collects in one place many distinct types of
information—an address, a note, a prescription, a bank statement, a
video—that reveal much more in combination than any isolated
record. Second, a cell phone’s capacity allows even just one type
of information to convey far more than previously possible. The sum
of an individual’s private life can be reconstructed through a
thousand photographs labeled with dates, locations, and
descriptions; the same cannot be said of a photograph or two of
loved ones tucked into a wallet. Third, the data on a phone can
date back to the purchase of the phone, or even earlier. A person
might carry in his pocket a slip of paper reminding him to call Mr.
Jones; he would not carry a record of all his communications with
Mr. Jones for the past several months, as would routinely be kept
on a phone.[ 1 ]

															     Finally, there is an
element of pervasiveness that characterizes cell phones but not
physical records. Prior to the digital age, people did not
typically carry a cache of sensitive personal information with them
as they went about their day. Now it is the person who is not
carrying a cell phone, with all that it contains, who is the
exception. According to one poll, 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. See Harris Interactive, 2013 Mobile Consumer Habits Study
(June 2013). A decade ago police officers searching an arrestee
might have occasionally stumbled across a highly personal item such
as a diary. See, e.g., United States v. Frankenberry, 387
F. 2d 337 (CA2 1967) (per curiam). But those discoveries were
likely to be few and far between. Today, by contrast, it is no
exaggeration to say that many of the more than 90% of American
adults who own a cell phone keep on their person a digital record
of nearly every aspect of their lives—from the mundane to the
intimate. See Ontario v. Quon, 560 U. S. 746, 760 (2010) .
Allowing the police to scrutinize such records on a routine basis
is quite different from allowing them to search a personal item or
two in the occasional case.

															     Although the data
stored on a cell phone is distinguished from physical records by
quantity alone, certain types of data are also qualitatively
different. An Internet search and browsing history, for example,
can be found on an Internet-enabled phone and could reveal an
individual’s private interests or concerns—perhaps a search for
certain symptoms of disease, coupled with frequent visits to WebMD.
Data on a cell phone can also reveal where a person has been.
Historic location information is a stand-ard feature on many smart
phones and can reconstruct someone’s specific movements down to the
minute, not only around town but also within a particular building.
See United States v. Jones, 565 U. S. ___, ___ (2012)
(Sotomayor, J., concurring) (slip op., at 3) (“GPS monitoring
generates a precise, comprehensive record of a person’s public
movements that reflects a wealth of detail about her familial,
political, professional, religious, and sexual associations.”).

															     Mobile application
software on a cell phone, or “apps,” offer a range of tools for
managing detailed information about all aspects of a person’s life.
There are apps for Democratic Party news and Republican Party news;
apps for alcohol, drug, and gambling addictions; apps for sharing
prayer requests; apps for tracking pregnancy symptoms; apps for
planning your budget; apps for every conceivable hobby or pastime;
apps for improving your romantic life. There are popular apps for
buying or selling just about anything, and the records of such
transactions may be accessible on the phone indefinitely. There are
over a million apps available in each of the two major app stores;
the phrase “there’s an app for that” is now part of the popular
lexicon. The average smart phone user has installed 33 apps, which
together can form a revealing montage of the user’s life. See Brief
for Electronic Privacy Information Center as Amicus Curiae in No.
13–132, p. 9.

															     In 1926, Learned Hand
observed (in an opinion later quoted in Chimel) that it is “a
totally different thing to search a man’s pockets and use against
him what they contain, from ransacking his house for everything
which may incriminate him.” United States v. Kirschenblatt, 16
F. 2d 202, 203 (CA2). If his pockets contain a cell phone,
however, that is no longer true. Indeed, a cell phone search would
typically expose to the government far more than the most
exhaustive search of a house: A phone not only contains in digital
form many sensitive records previ-ously found in the home; it also
contains a broad array of private information never found in a home
in any form—unless the phone is.

															2

															     To further complicate
the scope of the privacy interests at stake, the data a user views
on many modern cell phones may not in fact be stored on the device
itself. Treating a cell phone as a container whose contents may be
searched incident to an arrest is a bit strained as an initial
matter. See New York v. Belton, 453 U. S. 454, 460, n. 4
(1981) (describing a “container” as “any object capable of holding
another object”). But the analogy crumbles entirely when a cell
phone is used to access data located elsewhere, at the tap of a
screen. That is what cell phones, with increasing frequency, are
designed to do by taking advantage of “cloud computing.” Cloud
computing is the capacity of Internet-connected devices to display
data stored on remote servers rather than on the device itself.
Cell phone users often may not know whether particular information
is stored on the device or in the cloud, and it generally makes
little difference. See Brief for Electronic Privacy Information
Center in No. 13–132, at 12–14, 20. Moreover, the same type of data
may be stored locally on the device for one user and in the cloud
for another.

															     The United States
concedes that the search incident to arrest exception may not be
stretched to cover a search of files accessed remotely—that is, a
search of files stored in the cloud. See Brief for United States in
No. 13–212, at 43–44. Such a search would be like finding a key in
a suspect’s pocket and arguing that it allowed law enforcement to
unlock and search a house. But officers searching a phone’s data
would not typically know whether the information they are viewing
was stored locally at the time of the arrest or has been pulled
from the cloud.

															     Although the Government
recognizes the problem, its proposed solutions are unclear. It
suggests that officers could disconnect a phone from the network
before searching the device—the very solution whose feasibility it
contested with respect to the threat of remote wiping. Compare Tr.
of Oral Arg. in No. 13–132, at 50–51, with Tr. of Oral Arg. in No.
13–212, pp. 13–14. Alternatively, the Government proposes that law
enforcement agencies “develop protocols to address” concerns raised
by cloud computing. Reply Brief in No. 13–212, pp. 14–15. Probably
a good idea, but the Founders did not fight a revolution to gain
the right to government agency protocols. The possibility that a
search might extend well beyond papers and effects in the physical
proximity of an arrestee is yet another reason that the privacy
interests here dwarf those in Robinson.

															C

															     Apart from their
arguments for a direct extension of Robinson, the United States and
California offer various fallback options for permitting
warrantless cell phone searches under certain circumstances. Each
of the proposals is flawed and contravenes our general preference
to provide clear guidance to law enforcement through categorical
rules. “[I]f police are to have workable rules, the balancing of
the competing interests . . . ‘must in large part be done
on a categorical basis—not in an ad hoc, case-by-case fashion
by individual police officers.’ ” Michigan v. Summers, 452
U. S. 692, 705, n. 19 (1981) (quoting Dunaway v. New York, 442
U. S. 200 –220 (1979) (White, J., concurring)).

															     The United States first
proposes that the Gant standard be imported from the vehicle
context, allowing a warrantless search of an arrestee’s cell phone
whenever it is reasonable to believe that the phone contains
evidence of the crime of arrest. But Gant relied on “circumstances
unique to the vehicle context” to endorse a search solely for the
purpose of gathering evidence. 556 U. S., at 343. Justice
Scalia’s Thornton opinion, on which Gant was based, explained that
those unique circumstances are “a reduced expectation of privacy”
and “heightened law enforcement needs” when it comes to motor
vehicles. 541 U. S., at 631; see also Wyoming v. Houghton, 526
U. S., at 303–304. For reasons that we have explained, cell
phone searches bear neither of those characteristics.

															     At any rate, a Gant
standard would prove no practical limit at all when it comes to
cell phone searches. In the vehicle context, Gant generally
protects against searches for evidence of past crimes. See 3 W.
LaFave, Search and Seizure §7.1(d), at 709, and n. 191. In the cell
phone context, however, it is reasonable to expect that
incriminating information will be found on a phone regardless of
when the crime occurred. Similarly, in the vehicle context Gant
restricts broad searches resulting from minor crimes such as
traffic violations. See id., §7.1(d), at 713, and n. 204. That
would not necessarily be true for cell phones. It would be a
particularly inexperienced or unimaginative law enforcement officer
who could not come up with sev-eral reasons to suppose evidence of
just about any crime could be found on a cell phone. Even an
individual pulled over for something as basic as speeding might
well have locational data dispositive of guilt on his phone. An
individual pulled over for reckless driving might have evidence on
the phone that shows whether he was texting while driving. The
sources of potential pertinent information are virtually unlimited,
so applying the Gant standard to cell phones would in effect give
“police officers unbridled discretion to rummage at will among a
person’s private effects.” 556 U. S., at 345.

															     The United States also
proposes a rule that would restrict the scope of a cell phone
search to those areas of the phone where an officer reasonably
believes that infor-mation relevant to the crime, the arrestee’s
identity, or officer safety will be discovered. See Brief for
United States in No. 13–212, at 51–53. This approach would again
impose few meaningful constraints on officers. The proposed
categories would sweep in a great deal of information, and officers
would not always be able to discern in advance what information
would be found where.

															     We also reject the
United States’ final suggestion that officers should always be able
to search a phone’s call log, as they did in Wurie’s case. The
Government relies on Smith v. Maryland, 442 U. S. 735 (1979) ,
which held that no warrant was required to use a pen register at
telephone company premises to identify numbers dialed by a
particular caller. The Court in that case, however, concluded that
the use of a pen register was not a “search” at all under the
Fourth Amendment. See id., at 745–746. There is no dispute here
that the officers engaged in a search of Wurie’s cell phone.
Moreover, call logs typically contain more than just phone numbers;
they include any identifying information that an individual might
add, such as the label “my house” in Wurie’s case.

															     Finally, at oral
argument California suggested a different limiting principle, under
which officers could search cell phone data if they could have
obtained the same information from a pre-digital counterpart. See
Tr. of Oral Arg. in No. 13–132, at 38–43; see also Flores-Lopez,
670 F. 3d, at 807 (“If police are entitled to open a pocket
diary to copy the owner’s address, they should be entitled to turn
on a cell phone to learn its number.”). But the fact that a search
in the pre-digital era could have turned up a photograph or two in
a wallet does not justify a search of thousands of photos in a
digital gallery. The fact that someone could have tucked a paper
bank statement in a pocket does not justify a search of every bank
statement from the last five years. And to make matters worse, such
an analogue test would allow law enforcement to search a range of
items contained on a phone, even though people would be unlikely to
carry such a variety of information in physical form. In Riley’s
case, for example, it is implausible that he would have strolled
around with video tapes, photo albums, and an address book all
crammed into his pockets. But because each of those items has a
pre-digital analogue, police under California’s proposal would be
able to search a phone for all of those items—a significant
diminution of privacy.

															     In addition, an
analogue test would launch courts on a difficult line-drawing
expedition to determine which digital files are comparable to
physical records. Is an e-mail equivalent to a letter? Is a
voicemail equivalent to a phone message slip? It is not clear how
officers could make these kinds of decisions before conducting a
search, or how courts would apply the proposed rule after the fact.
An analogue test would “keep defendants and judges guessing for
years to come.” Sykes v. United States, 564 U. S. 1 , ___
(2011) (Scalia, J., dissenting) (slip op., at 7) (discussing the
Court’s analogue test under the Armed Career Criminal Act).

															IV

															     We cannot deny that
our decision today will have an impact on the ability of law
enforcement to combat crime. Cell phones have become important
tools in facilitating coordination and communication among members
of criminal enterprises, and can provide valuable incriminating
information about dangerous criminals. Privacy comes at a cost.

															     Our holding, of course,
is not that the information on a cell phone is immune from search;
it is instead that a warrant is generally required before such a
search, even when a cell phone is seized incident to arrest. Our
cases have historically recognized that the warrant requirement is
“an important working part of our machinery of gov-ernment,” not
merely “an inconvenience to be somehow ‘weighed’ against the claims
of police efficiency.” Coolidge v. New Hampshire, 403 U. S.
443, 481 (1971) . Recent technological advances similar to those
discussed here have, in addition, made the process of obtaining a
warrant itself more efficient. See McNeely, 569 U. S., at ___
(slip op., at 11–12); id., at ___ (Roberts, C. J., concurring
in part and dissenting in part) (slip op., at 8) (describing
jurisdiction where “police officers can e-mail warrant requests to
judges’ iPads [and] judges have signed such warrants and e-mailed
them back to officers in less than 15 minutes”).

															     Moreover, even though
the search incident to arrest exception does not apply to cell
phones, other case-specific exceptions may still justify a
warrantless search of a particular phone. “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., at ___ (slip
op., at 6) (quoting Mincey v. Arizona, 437 U. S. 385, 394
(1978) ). Such exigencies could include the need to prevent the
imminent destruction of evidence in individual cases, to pursue a
fleeing suspect, and to assist persons who are seriously injured or
are threatened with imminent injury. 563 U. S., at ___. In
Chadwick, for example, the Court held that the exception for
searches incident to arrest did not justify a search of the trunk
at issue, but noted that “if officers have reason to believe that
luggage contains some immediately dangerous instrumentality, such
as explosives, it would be foolhardy to transport it to the station
house without opening the luggage.” 433 U. S., at 15, n.
9.

															     In light of the
availability of the exigent circumstances exception, there is no
reason to believe that law enforcement officers will not be able to
address some of the more extreme hypotheticals that have been
suggested: a suspect texting an accomplice who, it is feared, is
preparing to detonate a bomb, or a child abductor who may have
information about the child’s location on his cell phone. The
defendants here recognize—indeed, they stress—that such
fact-specific threats may justify a warrantless search of cell
phone data. See Reply Brief in No. 13–132, at 8–9; Brief for
Respondent in No. 13–212, at 30, 41. The critical point is that,
unlike the search incident to arrest exception, the exigent
circumstances exception requires a court to examine whether an
emergency justified a warrantless search in each particular case.
See McNeely, supra, at ___ (slip op., at 6).[ 2 ]

															*  *  *

															     Our cases have
recognized 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. Opposition to such searches was in fact one of
the driving forces behind the Revolution itself. In 1761, the
patriot James Otis delivered a speech in Boston denouncing the use
of writs of assistance. A young John Adams was there, and he would
later write that “[e]very man of a crowded audience appeared to me
to go away, as I did, ready to take arms against writs of
assistance.” 10 Works of John Adams 247–248 (C. Adams ed. 1856).
According to Adams, Otis’s speech was “the first scene of the first
act of opposition to the arbitrary claims of Great Britain. Then
and there the child Independence was born.” Id., at 248 (quoted in
Boyd v. United States, 116 U. S. 616, 625 (1886) ).

															     Modern cell phones are
not just another technological convenience. With all they contain
and all they may reveal, they hold for many Americans “the
privacies of life,” Boyd, supra, at 630. The fact that technology
now allows an individual to carry such information in his hand does
not make the information any less worthy of the protection for
which the Founders fought. Our answer to the question of what
police must do before searching a cell phone seized incident to an
arrest is accordingly simple—get a warrant.

															     We reverse the judgment
of the California Court of Appeal in No. 13–132 and remand the case
for further proceedings not inconsistent with this opinion. We
affirm the judgment of the First Circuit in No. 13–212.

															It is so ordered. Notes 1 Because the United States
and California agree that these cases involve incident to arrest,
these cases do not implicate the question whether the collection or
inspection of aggregated digital information amounts to a search
under other circumstances. 2 In Wurie’s case, for
example, the dissenting First Circuit judge argued that exigent
circumstances could have justified a search of Wurie’s phone. See
728 F. 3d 1, 17 (2013) (opinion of Howard, J.) (discussing the
repeated unanswered calls from “my house,” the suspected location
of a drug stash). But the majority concluded that the Government
had not made an exigent circumstances argument. See at 1. The
Government acknowledges the same in this Court. See Brief for
United States in No. 13–212, p. 28, n. 8. SUPREME COURT OF THE UNITED STATES

															_________________

															Nos. 13–132 and 13–212

															_________________

															DAVID LEON RILEY, PETITIONER

															13–132      v.

															CALIFORNIA

															on writ of certiorari to the court of appeal
of cali-fornia, fourth appellate district, division one

															UNITED STATES, PETITIONER

															13–212      v.

															BRIMA WURIE

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

															[June 25, 2014]

															     Justice Alito,
concurring in part and concurring in the judgment.

															     I agree with the Court
that law enforcement officers, in conducting a lawful search
incident to arrest, must generally obtain a warrant before
searching information stored or accessible on a cell phone. I write
separately to address two points.

															I

															A

															     First, I am not
convinced at this time that the ancient rule on searches incident
to arrest is based exclusively (or even primarily) on the need to
protect the safety of arresting officers and the need to prevent
the destruction of evidence. Cf. ante, at 9. This rule antedates
the adoption of the Fourth Amendment by at least a century. See T.
Clancy, The Fourth Amendment: Its History and Interpretation 340
(2008); T. Taylor, Two Studies in Constitutional Interpretation 28
(1969); Amar, Fourth Amendment First Principles, 107 Harv. L. Rev.
757, 764 (1994). In Weeks v. United States, 232 U. S. 383, 392
(1914) , we held that the Fourth Amendment did not disturb this
rule. See also Taylor, supra, at 45; Stuntz, The Substantive
Origins of Criminal Procedure, 105 Yale L. J. 393, 401 (1995) (“The
power to search incident to arrest—a search of the arrested
suspect’s person . . .—was well established in the
mid-eighteenth century, and nothing in . . . the Fourth
Amendment changed that”). And neither in Weeks nor in any of the
authorities discussing the old common-law rule have I found any
suggestion that it was based exclusively or primarily on the need
to protect arresting officers or to prevent the destruction of
evidence.

															     On the contrary, when
pre-Weeks authorities discussed the basis for the rule, what was
mentioned was the need to obtain probative evidence. For example,
an 1839 case stated that “it is clear, and beyond doubt, that
. . . constables . . . are entitled, upon a
lawful arrest by them of one charged with treason or felony, to
take and detain prop-erty found in his possession which will form
material evi-dence in his prosecution for that crime.” See Dillon
v. O’Brien, 16 Cox Crim. Cas. 245, 249–251 (1887) (citing Regina,
v. Frost, 9 Car. & P. 129, 173 Eng. Rep. 771)). The court noted
that the origins of that rule “deriv[e] from the interest which the
State has in a person guilty (or reasonably believed to be guilty)
of a crime being brought to justice, and in a prosecution, once
commenced, being determined in due course of law.” 16 Cox Crim.
Cas., at 249–250. See also Holker v. Hennessey, 141 Mo. 527,
537–540, 42 S. W. 1090, 1093 (1897).

															     Two 19th-century
treatises that this Court has previ-ously cited in connection with
the origin of the search-incident-to-arrest rule, see Weeks, supra,
at 392, suggest the same rationale. See F. Wharton, Criminal
Pleading and Practice §60, p. 45 (8th ed. 1880) (“Those arresting a
defendant are bound to take from his person any articles which may
be of use as proof in the trial of the offense with which the
defendant is charged”); J. Bishop, Criminal Procedure §§210–212, p.
127 (2d ed. 1872) (if an arresting officer finds “about the
prisoner’s person, or otherwise in his possession, either goods or
moneys which there is reason to believe are connected with the
supposed crime as its fruits, or as the instruments with which it
was committed, or as directly furnishing evidence relating to the
transaction, he may take the same, and hold them to be disposed of
as the court may direct”).

															     What ultimately
convinces me that the rule is not closely linked to the need for
officer safety and evidence preser-vation is that these rationales
fail to explain the rule’s well-recognized scope. It has long been
accepted that written items found on the person of an arrestee may
be examined and used at trial.[ 1 ]* But once these items are taken away from an arrestee
(something that obviously must be done before the items are read),
there is no risk that the arrestee will destroy them. Nor is there
any risk that leaving these items unread will endanger the
arresting officers.

															     The idea that officer
safety and the preservation of evidence are the sole reasons for
allowing a warrantless search incident to arrest appears to derive
from the Court’s reasoning in Chimel v. California, 395 U. S.
752 (1969) , a case that involved the lawfulness of a search of the
scene of an arrest, not the person of an arrestee. As I have
explained, Chimel’s reasoning is questionable, see Arizona v. Gant,
556 U. S. 332 –363 (2009) (Alito, J., dissenting), and I think
it is a mistake to allow that reasoning to affect cases like these
that concern the search of the person of arrestees.

															B

															     Despite my view on
the point discussed above, I agree that we should not mechanically
apply the rule used in the predigital era to the search of a cell
phone. Many cell phones now in use are capable of storing and
accessing a quantity of information, some highly personal, that no
person would ever have had on his person in hard-copy form. This
calls for a new balancing of law enforcement and privacy
interests.

															     The Court strikes this
balance in favor of privacy interests with respect to all cell
phones and all information found in them, and this approach leads
to anomalies. For example, the Court’s broad holding favors
information in digital form over information in hard-copy form.
Suppose that two suspects are arrested. Suspect number one has in
his pocket a monthly bill for his land-line phone, and the bill
lists an incriminating call to a long-distance number. He also has
in his a wallet a few snapshots, and one of these is incriminating.
Suspect number two has in his pocket a cell phone, the call log of
which shows a call to the same incriminating number. In addition, a
number of photos are stored in the memory of the cell phone, and
one of these is incriminating. Under established law, the police
may seize and examine the phone bill and the snapshots in the
wallet without obtaining a warrant, but under the Court’s holding
today, the information stored in the cell phone is out.

															     While the Court’s
approach leads to anomalies, I do not see a workable alternative.
Law enforcement officers need clear rules regarding searches
incident to arrest, and it would take many cases and many years for
the courts to develop more nuanced rules. And during that time, the
nature of the electronic devices that ordinary Americans carry on
their persons would continue to change.

															II

															     This brings me to my
second point. While I agree with the holding of the Court, I would
reconsider the question presented here if either Congress or state
legislatures, after assessing the legitimate needs of law
enforcement and the privacy interests of cell phone owners, enact
legislation that draws reasonable distinctions based on categories
of information or perhaps other variables.

															     The regulation of
electronic surveillance provides an instructive example. After this
Court held that electronic surveillance constitutes a search even
when no property interest is invaded, see Katz v. United States,
389 U. S. 347 –359 (1967), Congress responded by enacting
Title III of the Omnibus Crime Control and Safe Streets Act of
1968, 82Stat. 211. See also 18 U. S. C. §2510
et seq. Since that time, electronic surveillance has been
governed primarily, not by decisions of this Court, but by the
stat-ute, which authorizes but imposes detailed restrictions on
electronic surveillance. See ibid.

															     Modern cell phones are
of great value for both lawful and unlawful purposes. They can be
used in committing many serious crimes, and they present new and
difficult law enforcement problems. See Brief for United States in
No. 13–212, pp. 2–3. At the same time, because of the role that
these devices have come to play in contemporary life, searching
their contents implicates very sensitive privacy interests that
this Court is poorly positioned to understand and evaluate. Many
forms of modern technology are making it easier and easier for both
government and private entities to amass a wealth of information
about the lives of ordinary Americans, and at the same time, many
ordinary Americans are choosing to make public much information
that was seldom revealed to outsiders just a few decades ago.

															     In light of these
developments, it would be very unfortunate if privacy protection in
the 21st century were left primarily to the federal courts using
the blunt instrument of the Fourth Amendment. Legislatures, elected
by the people, are in a better position than we are to assess and
respond to the changes that have already occurred and those that
almost certainly will take place in the future. Notes 1 * Cf. v. , –802, and
n. 1 (1971) (diary); v. , –199 (1927) (ledgerand bills); v. ,
, overruled on other grounds, v. , –301 (1967) (papers); see v. ,
995 F. 2d 776, 778 (CA7 1993) (address book); v. , 949 F. 2d
151, 153 (CA5 1991) (notebook); v. , 877 F. 2d 1341 (CA7 1989)
(wallet); v. , 764 F. 2d 1514, 1527 (CA11 1985) (wallet and
papers); v. , 669 F. 2d 1374, 1383–1384 (CA11 1982) (documents
found in a wallet); v. , 596 F. 2d 674, 677 (CA5 1979), cert.
denied, (paper found in a pocket); v. , 520 F. 2d 1256, 1267–1268
(CA7 1975) (three notebooks and meeting minutes); v. , 126 F. 2d
585, 587 (CA10 1942) (papers, circulars, advertising matter,
“memoranda containing various names and addresses”); v. , 56 F. 2d
753, 755 (CA2 1932) (“numerous prescriptions blanks” and a check
book). See also 3 W. LaFave, Search and Seizure §5.2(c), p. 144
(5th ed. 2012) (“Lower courts, in applying Robinson, have deemed
evidentiary searches of an arrested person to be virtually
unlimited”); W. Cuddihy, FourthAmendment: Origins and Original
Meaning 847–848 (1990) (in the pre-Constitution colonial era,
“[a]nyone arrested could expect that not only his surface clothing
but his body, luggage, and saddlebags would be
searched”).

Summary: The Supreme Court ruled that police officers cannot search digital information on a cell phone without a warrant, even if the phone was seized from someone who was arrested. This decision recognizes the sensitive privacy interests associated with modern cell phones and digital technology, and highlights the need for legislative action to address these complex issues.