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

															_________________

															No. 13–604

															_________________

															NICHOLAS BRADY HEIEN, PETITIONER v. NORTH CAROLINA

															on writ of certiorari to the supreme court of north carolina

															[December 15, 2014] Chief Justice Roberts delivered the opinion of the
Court. The Fourth Amendment prohibits “unreasonable searches and
seizures.” Under this standard, a search or seizure may be
permissible even though the justification for the action includes a
reasonable factual mistake. An officer might, for example, stop a
motorist for traveling alone in a high-occupancy vehicle lane, only
to discover upon approaching the car that two children are slumped
over asleep in the back seat. The driver has not violated the law,
but neither has the officer violated the Fourth Amendment.

															But what if the police officer’s reasonable mistake is not one
of fact but of law? In this case, an officer stopped a vehicle
because one of its two brake lights was out, but a court later
determined that a single working brake light was all the law
required. The question presented is whether such a mistake of law
can nonetheless give rise to the reasonable suspicion necessary to
uphold the seizure under the Fourth Amendment. We hold that it can.
Because the officer’s mistake about the brake-light law was
reasonable, the stop in this case was lawful under the Fourth
Amendment.

															I

															On the morning of April 29, 2009, Sergeant Matt Da-risse of the
Surry County Sheriff’s Department sat in his patrol car near
Dobson, North Carolina, observing northbound traffic on Interstate
77. Shortly before 8 a.m., a Ford Escort passed by. Darisse thought
the driver looked “very stiff and nervous,” so he pulled onto the
interstate and began following the Escort. A few miles down the
road, the Escort braked as it approached a slower vehicle, but only
the left brake light came on. Noting the faulty right brake light,
Darisse activated his vehicle’s lights and pulled the Escort over.
App. 4–7, 15–16.

															Two men were in the car: Maynor Javier Vasquez sat behind the
wheel, and petitioner Nicholas Brady Heien lay across the rear
seat. Sergeant Darisse explained to Vasquez that as long as his
license and registration checked out, he would receive only a
warning ticket for the broken brake light. A records check revealed
no problems with the documents, and Darisse gave Vasquez the
warning ticket. But Darisse had become suspicious during the course
of the stop—Vasquez appeared nervous, Heien remained lying down the
entire time, and the two gave inconsistent answers about their
destination. Darisse asked Vasquez if he would be willing to answer
some questions. Vasquez assented, and Darisse asked whether the men
were transporting various types of contraband. Told no, Darisse
asked whether he could search the Escort. Vasquez said he had no
objection, but told Darisse he should ask Heien, because Heien
owned the car. Heien gave his consent, and Darisse, aided by a
fellow officer who had since arrived, began a thorough search of
the vehicle. In the side compartment of a duffle bag, Darisse found
a sandwich bag containing cocaine. The officers arrested both men.
366 N. C. 271, 272–273, 737 S. E. 2d 351, 352–353 (2012);
App. 5–6, 25, 37.

															The State charged Heien with attempted trafficking in cocaine.
Heien moved to suppress the evidence seized from the car,
contending that the stop and search had violated the Fourth
Amendment of the United States Constitution. After a hearing at
which both officers testified and the State played a video
recording of the stop, the trial court denied the suppression
motion, concluding that the faulty brake light had given Sergeant
Darisse reasonable suspicion to initiate the stop, and that Heien’s
subsequent consent to the search was valid. Heien pleaded guilty
but reserved his right to appeal the suppression decision. App. 1,
7–10, 12, 29, 43–44.

															The North Carolina Court of Appeals reversed. 214 N. C.
App. 515, 714 S. E. 2d 827 (2011). The initial stop was not valid,
the court held, because driving with only one working brake light
was not actually a violation of North Carolina law. The relevant
provision of the vehicle code provides that a car must be

															“equipped with a stop lamp on the rear of the vehicle. The stop
lamp shall display a red or amber light visible from a distance of
not less than 100 feet to the rear in normal sunlight, and shall be
actuated upon application of the service (foot) brake. The stop
lamp may be incorporated into a unit with one or moreother rear
lamps.” N. C. Gen. Stat. Ann. §20–129(g) (2007).

															Focusing on the statute’s references to “a stop lamp” and “[t]he
stop lamp” in the singular, the court concluded that a vehicle is
required to have only one working brake light—which Heien’s vehicle
indisputably did. The justification for the stop was therefore
“objectively unreason-able,” and the stop violated the Fourth
Amendment. 214 N. C. App., at 518–522, 714 S. E. 2d, at
829–831.

															The State appealed, and the North Carolina Supreme Court
reversed. 366 N. C. 271, 737 S. E. 2d 351. Noting that
the State had chosen not to seek review of the Court of Appeals’
interpretation of the vehicle code, the North Carolina Supreme
Court assumed for purposes of its decision that the faulty brake
light was not a violation. Id., at 275, 737 S. E. 2d,
at 354. But the court concluded that, for several reasons, Sergeant
Darisse could have reasonably, even if mistakenly, read the vehicle
code to require that both brake lights be in good working order.
Most notably, a nearby code provision requires that “all originally
equipped rear lamps” be functional. Id., at 282–283, 737
S. E. 2d, at 358–359 (quoting N. C. Gen. Stat. Ann.
§20–129(d)). Because Sergeant Darisse’s mistaken understanding of
the vehicle code was reasonable, the stop was valid. “An officer
may make a mistake, including a mistake of law, yet still act
reasonably under the circumstances. . . . [W]hen an officer acts
reasonably under the circumstances, he is not violating the Fourth
Amendment.” Id., at 279, 737 S. E. 2d, at 356.

															The North Carolina Supreme Court remanded to the Court of
Appeals to address Heien’s other arguments for suppression (which
are not at issue here). Id., at 283, 737 S. E. 2d, at
359. The Court of Appeals rejected those arguments and affirmed the
trial court’s denial of his motion to suppress. ___ N. C. App.
___, 741 S. E. 2d 1 (2013). The North Carolina Supreme Court
affirmed in turn. 367 N. C. 163, 749 S. E. 2d 278 (2013).
We granted certiorari. 572 U. S. ___ (2014).

															II

															The Fourth Amendment provides:

															“The right of the people to be secure in their persons, houses,
papers, and effects, against unreason-able 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.”

															A traffic stop for a suspected violation of law is a “seizure”
of the occupants of the vehicle and therefore must be conducted in
accordance with the Fourth Amendment. Brendlin v. California , 551 U. S. 249 –259 (2007). All parties
agree that to justify this type of seizure, officers need only
“reasonable suspicion”—that is, “a particularized and objective
basis for suspecting the particular person stopped” of breaking the
law. Prado Navarette v. California , 572 U. S.
___, ___ (2014) (slip op., at 3) (internal quotation marks
omitted). The question here is whether reasonable suspicion can
rest on a mistaken understanding of the scope of a legal
prohibition. We hold that it can.

															As the text indicates and we have repeatedly affirmed, “the
ultimate touchstone of the Fourth Amendment is
‘reasonableness.’ ” Riley v. California , 573
U. S. ___, ___ (2014) (slip op., at 5) (some internal
quotation marks omitted). To be reasonable is not to be perfect,
and so the Fourth Amendment allows for some mistakes on the part of
government officials, giving them “fair leeway for enforcing the
law in the community’s protection.” Brinegar v. United
States , 338 U. S. 160, 176 (1949) . We have recognized
that searches and seizures based on mistakes of fact can be
reasonable. The warrantless search of a home, for instance, is
reasonable if undertaken with the consent of a resident, and
remains lawful when officers obtain the consent of someone who
reasonably appears to be but is not in fact a resident. See Illinois v. Rodriguez , 497 U. S. 177 –186
(1990). By the same token, if officers with probable cause to
arrest a suspect mistakenly arrest an individual matching the
suspect’s description, neither the seizure nor an accompanying
search of the arrestee would be unlawful. See Hill v. California , 401 U. S. 797 –805 (1971). The limit is
that “the mistakes must be those of reasonable men.” Brinegar , supra, at 176.

															But reasonable men make mistakes of law, too, and such mistakes
are no less compatible with the concept of reasonable suspicion.
Reasonable suspicion arises from the combination of an officer’s
understanding of the facts and his understanding of the relevant
law. The officer may be reasonably mistaken on either ground.
Whether the facts turn out to be not what was thought, or the law
turns out to be not what was thought, the result is the same: the
facts are outside the scope of the law. There is no reason, under
the text of the Fourth Amendment or our precedents, why this same
result should be acceptable when reached by way of a reasonable
mistake of fact, but not when reached by way of a similarly
reasonable mistake of law.

															The dissent counters that our cases discussing probable cause
and reasonable suspicion, most notably Ornelas v. United
States , 517 U. S. 690 –697 (1996), have contained
“scarcely a peep” about mistakes of law. Post , at 2–3
(opinion of Sotomayor, J.). It would have been surprising, of
course, if they had, since none of those cases involved a mistake
of law.

															Although such recent cases did not address mistakes of law,
older precedents did. In fact, cases dating back two centuries
support treating legal and factual errors alike in this context.
Customs statutes enacted by Congress not long after the founding
authorized courts to issue certificates indemnifying customs
officers against damages suits premised on unlawful seizures. See, e.g., Act of Mar. 2, 1799, ch. 22, §89, 1Stat. 695–696.
Courts were to issue such certificates on a showing that the
officer had “reasonable cause”—a synonym for “probable cause”—for
the challenged seizure. Ibid. ; see Stacey v. Emery , 97 U. S. 642, 646 (1878); United States v. Riddle , 5 Cranch 311 (1809). In United States v. Riddle , a customs officer seized goods on the ground that
the English shipper had violated the customs laws by preparing an
invoice that undervalued the merchandise, even though the American
consignee declared the true value to the customs collector. Chief
Justice Marshall held that there had been no violation of the
customs law because, whatever the shipper’s intention, the
consignee had not actually attempted to defraud the Government.
Nevertheless, because “the construction of the law was liable to
some question,” he affirmed the issuance of a certificate of
probable cause: “A doubt as to the true construction of the law is as reasonable a cause for seizure as a doubt
respecting the fact.” Id. , at 313.

															This holding—that reasonable mistakes of law, like those of
fact, would justify certificates of probable cause—was reiterated
in a number of 19th-century decisions. See, e.g., The
Friendship , 9 F. Cas. 825, 826 (No. 5,125) (CC Mass. 1812)
(Story, J.); United States v. The Reindeer , 27
F. Cas. 758, 768 (No. 16,145) (CC RI 1848); United
States v. The Recorder , 27 F. Cas. 723 (No. 16,130)
(CC SDNY 1849). By the Civil War, there had been “numerous cases in
which [a] captured vessel was in no fault, and had not, under a
true construction of the law, presented even ground of suspicion,
and yet the captor was exonerated because he acted under an honest
mistake of the law.” The La Manche , 14 F. Cas. 965, 972
(No. 8,004) (D Mass. 1863). Riddle and its progeny are not directly on point. Chief
Justice Marshall was not construing the Fourth Amendment, and a
certificate of probable cause functioned much like a modern-day
finding of qualified immunity, which depends on an inquiry distinct
from whether an officer has committed a constitutional violation.
See, e.g., Carroll v. Carman , ante, at
7 ( per curiam ). But Chief Justice Marshall was nevertheless
explaining the concept of probable cause, which, he noted
elsewhere, “in all cases of seizure, has a fixed and well known
meaning. It imports a seizure made under circumstances which
warrant suspicion.” Locke v. United States , 7 Cranch
339, 348 (1813). We have said the phrase “probable cause” bore this
“fixed and well known meaning” in the Fourth Amendment, see Brinegar , supra, at 175, and n. 14, and Riddle illustrates that it encompassed suspicion based on
reasonable mistakes of both fact and law. No decision of this Court
in the two centuries since has undermined that
understanding.[ 1 ]

															The contrary conclusion would be hard to reconcile with a much
more recent precedent. In Michigan v. DeFillippo , 443
U. S. 31 (1979) , we addressed the validity of an arrest made
under a criminal law later declared unconstitu-tional. A Detroit
ordinance that authorized police officers to stop and question
individuals suspected of criminal activ-ity also made it an offense
for such an individual “to refuse to identify himself and produce
evidence of his identity.” Id., at 33. Detroit police
officers sent to investigate a report of public intoxication
arrested Gary DeFillippo after he failed to identify himself. A
search incident to arrest uncovered drugs, and DeFillippo was
charged with possession of a controlled substance. The Michigan
Court of Appeals ordered the suppression of the drugs, concluding
that the identification ordinance was unconstitutionally vague and
that DeFillippo’s arrest was therefore invalid. Id., at
34–35.

															Accepting the unconstitutionality of the ordinance as a given,
we nonetheless reversed. At the time the officers arrested
DeFillippo, we explained, “there was no controlling precedent that
this ordinance was or was not constitutional, and hence the conduct
observed violated a presumptively valid ordinance.” Id., at
37. Acknowledging that the outcome might have been different had
the ordinance been “grossly and flagrantly unconstitutional,” we
concluded that under the circumstances “there was abundant probable
cause to satisfy the constitutional prerequisite for an arrest.” Id., at 37–38.

															The officers were wrong in concluding that DeFillippo was guilty
of a criminal offense when he declined to iden-tify himself. That a
court only later declared the ordinance unconstitutional
does not change the fact that DeFillippo’s conduct was lawful when
the officers observed it. See Danforth v. Minnesota ,
552 U. S. 264, 271 (2008) . But the officers’ assumption that
the law was valid was reason-able, and their observations gave them
“abundant probable cause” to arrest DeFillippo. 443 U. S., at
37. Although DeFillippo could not be prosecuted under the
identifica-tion ordinance, the search that turned up the drugs was
constitutional.

															Heien struggles to recast DeFillippo as a case solely
about the exclusionary rule, not the Fourth Amendment itself. In
his view, the officers’ mistake of law resulted in a violation the
Fourth Amendment, but suppression of the drugs was not the proper
remedy. We did say in a footnote that suppression of the evidence
found on DeFillippo would serve none of the purposes of the
exclusionary rule. See id., at 38, n. 3. But that
literally marginal discussion does not displace our express holding
that the arrest was constitutionally valid because the officers had
probable cause. See id., at 40. Nor, contrary to Heien’s
suggestion, did either United States v. Leon , 468
U. S. 897 (1984) , or Illinois v. Gates , 462
U. S. 213 (1983) , somehow erase that holding and transform DeFillippo into an exclusionary rule decision. See Brief for
Petitioner 28–29. In Leon , we said DeFillippo paid
“attention to the purposes underlying the exclusionary rule,” but
we also clarified that it did “not involv[e] the scope of the rule
itself.” 468 U. S., at 911–912. As for Gates , only
Justice White’s separate opinion (joined by no other Justice)
discussed DeFillippo , and it acknowledged that
“ DeFillippo did not modify the exclusionary rule itself” but
instead “upheld the validity of an arrest.” 462 U. S., at 256,
n. 12 (opinion concurring in judgment).

															Heien is correct that in a number of decisions we have looked to
the reasonableness of an officer’s legal error in the course of
considering the appropriate remedy for a constitutional violation,
instead of whether there was a violation at all. See, e.g., Davis v. United States , 564 U. S. ___, ___
(2011) (slip op., at 11) (exclusionary rule); Illinois v. Krull , 480 U. S. 340 –360 (1987) (exclusionary rule); Wilson v. Layne , 526 U. S. 603, 615 (1999)
(qualified immunity); Anderson v. Creighton , 483
U. S. 635, 641 (1987) (qualified immunity). In those cases,
however, we had already found or assumed a Fourth Amendment
violation. An officer’s mistaken view that the conduct at issue did not give rise to such a violation—no matter how
reason-able—could not change that ultimate conclusion. See Brief
for Respondent 29–31; Brief for United States as Amicus
Curiae 30, n. 3. Any consideration of the reasonableness
of an officer’s mistake was therefore limited to the separate
matter of remedy.

															Here, by contrast, the mistake of law relates to the antecedent
question of whether it was reasonable for an officer to suspect
that the defendant’s conduct was illegal. If so, there was no
violation of the Fourth Amendment in the first place. None of the
cases Heien or the dissent cites precludes a court from considering
a reasonable mistake of law in addressing that question. Cf. Herring v. United States , 555 U. S. 135, 139
(2009) (assuming a Fourth Amendment violation while rejecting
application of the exclusionary rule, but noting that “[w]hen a
probable-cause determination was based on reasonable but mis-taken
assumptions, the person subjected to a search or seizure has not
necessarily been the victim of a constitutional violation”).

															Heien also contends that the reasons the Fourth Amendment allows
some errors of fact do not extend to errors of law. Officers in the
field must make factual assessments on the fly, Heien notes, and so
deserve a margin of error. In Heien’s view, no such margin is
appropriate for questions of law: The statute here either requires
one working brake light or two, and the answer does not turn on
anything “an officer might suddenly confront in the field.” Brief
for Petitioner 21. But Heien’s point does not consider the reality
that an officer may “suddenly confront” a situation in the field as
to which the application of a statute is unclear—however clear it
may later become. A law prohibiting “vehicles” in the park either
covers Segways or not, see A. Scalia & B. Garner, Reading Law:
The Interpretation of Legal Texts 36–38 (2012), but an officer will
nevertheless have to make a quick decision on the law the first
time one whizzes by.

															Contrary to the suggestion of Heien and amici , our
decision does not discourage officers from learning the law. The
Fourth Amendment tolerates only reasonable mistakes, and
those mistakes—whether of fact or of law—must be objectively reasonable. We do not examine the subjective understanding of the
particular officer involved. Cf. Whren v. United
States , 517 U. S. 806, 813 (1996) . And the inquiry is not
as forgiving as the one employed in the distinct context of
deciding whether an officer is entitled to qualified immunity for a
constitutional or statutory violation. Thus, an officer can gain no
Fourth Amendment advantage through a sloppy study of the laws he is
duty-bound to enforce.

															Finally, Heien and amici point to the well-known maxim,
“Ignorance of the law is no excuse,” and contend that itis
fundamentally unfair to let police officers get away with mistakes
of law when the citizenry is accorded no such leeway. Though this
argument has a certain rhetorical appeal, it misconceives the
implication of the maxim. The true symmetry is this: Just as an
individual generally cannot escape criminal liability based on a
mistaken understanding of the law, so too the government cannot
impose criminal liability based on a mistaken understanding of the
law. If the law required two working brake lights, Heien could not
escape a ticket by claiming he reasonably thought he needed only
one; if the law required only one, Sergeant Darisse could not issue
a valid ticket by claiming he reasonably thought drivers needed
two. But just because mistakes of law cannot justify either the
imposition or the avoidance of criminal liability, it does not
follow that they cannot justify an investigatory stop. And Heien is
not appealing a brake-light ticket; he is appealing a
cocaine-trafficking conviction as to which there is no asserted
mistake of fact or law.

															III

															Here we have little difficulty concluding that the officer’s
error of law was reasonable. Although the North Carolina statute at
issue refers to “ a stop lamp,” suggesting the need for only
a single working brake light, it also provides that “[t]he stop
lamp may be incorporated into a unit with one or more other rear lamps.” N. C. Gen. Stat. Ann. §20–129(g) (emphasis
added). The use of “other” suggests to the everyday reader of
English that a “stop lamp” is a type of “rear lamp.” And another
subsection of the same provision requires that vehicles “have all
originally equipped rear lamps or the equivalent in good working
order,” §20–129(d), arguably indicating that if a vehicle has
multiple “stop lamp[s],” all must be functional.

															The North Carolina Court of Appeals concluded that the “rear
lamps” discussed in subsection (d) do not include brake lights,
but, given the “other,” it would at least have been reasonable to
think they did. Both the majority and the dissent in the North
Carolina Supreme Court so concluded, and we agree. See 366
N. C., at 282–283, 737 S. E. 2d, at 358–359; id., at 283, 737 S. E. 2d, at 359 (Hudson, J., dissenting) (calling
the Court of Appeals’ decision “surprising”). This “stop lamp”
provision, moreover, had never been previously construed by North
Carolina’s appellate courts. See id., at 283, 737 S. E.
2d, at 359 (majority opinion). It was thus objectively reasonable
for an officer in Sergeant Darisse’s position to think that Heien’s
faulty right brake light was a violation of North Carolina law. And
because the mistake of law was reasonable, there was reasonable
suspicion justifying the stop.

															The judgment of the Supreme Court of North Carolina is

															Affirmed. Notes 1 The dissent contends that “the
tolerance of mistakes of law in cases like Riddle was a
result of the specific customs statute that Congress had enacted.” Post , at 8, n. 3 (citing The Apollon , 9 Wheat. 362,
373 (1824) (Story, J.)). The relevant portion of The
Apollon , however, addressed “the effect of probable
cause,” not what gave rise to it. Id. , at 372 (emphasis
added); see id., at 376 (finding it “unnecessary” to decide
whether probable cause existed because it “would not, under the
circumstances of this case, constitute a valid defence”). Justice
Story understandably did not cite Riddle or discuss its
tolerance of mistakes of law anywhere in The
Apollon . SUPREME COURT OF THE UNITED STATES

															_________________

															No. 13–604

															_________________

															NICHOLAS BRADY HEIEN, PETITIONER v. NORTH CAROLINA

															on writ of certiorari to the supreme court of north carolina

															[December 15, 2014]

															Justice Kagan, with whom Justice Ginsburg joins, concurring.

															I concur in full in the Court’s opinion, which explains why
certain mistakes of law can support the reasonable suspicion needed
to stop a vehicle under the Fourth Amendment. In doing so, the
Court correctly emphasizes that the “ Fourth Amendment tolerates
only . . . objectively reasonable” mistakes of
law. Ante , at 11. And the Court makes clear that the inquiry
into whether an officer’s mistake of law counts as objectively
reasonable “is not as forgiving as the one employed in the distinct
context of deciding whether an officer is entitled to qualified
immunity.” Ibid . I write separately to elaborate briefly on
those important limitations.[ 1 ]

															First, an officer’s “subjective understanding” is irrelevant: As
the Court notes, “[w]e do not examine” it at all. Ibid. That
means the government cannot defend an officer’s mistaken legal
interpretation on the ground that the officer was unaware of or
untrained in the law. And it means that, contrary to the dissenting
opinion in the court below, an officer’s reliance on “an incorrect
memo or training program from the police department” makes no
difference to the analysis. 366 N. C. 271, 284, 737 S. E.
2d 351, 360 (2012) (Hudson, J., dissenting). Those considerations
pertain to the officer’s subjective understanding of the law and
thus cannot help to justify a seizure.

															Second, the inquiry the Court permits today is more demanding
than the one courts undertake before awarding qualified immunity.
See Tr. of Oral Arg. 51 (Solicitor General stating that the two
tests “require essentially the opposite” showings); Brief for
Respondent 31–32 (making a similar point). Our modern qualified
immunity doctrine protects “all but the plainly incompetent or
those who knowingly violate the law.” Ashcroft v. al-Kidd , 563 U. S. ___, ___ (2011) (slip op., at 12)
(quoting Malley v. Briggs ,475 U. S. 335,341
(1986)). By contrast, Justice Story’s opinion in The
Friendship , 9 F. Cas. 825, 826 (No. 5,125) (CC Mass. 1812)
(cited ante, at 7), suggests the appropriate standard for
deciding when a legal error can support a seizure: when an officer
takes a reasonable view of a “vexata questio” on which different
judges “h[o]ld opposite opinions.” See Brief for United States as Amicus Curiae 26 (invoking that language). Or to make the
same point without the Latin, the test is satisfied when the law at
issue is “so doubtful in construction” that a reasonable judge
could agree with the officer’s view. The Friendship , 9
F. Cas., at 826.

															A court tasked with deciding whether an officer’s mistake of law
can support a seizure thus faces a straightforward question of
statutory construction. If the statute is genuinely ambiguous, such
that overturning the officer’s judgment requires hard interpretive
work, then the officer has made a reasonable mistake. But if not,
not. As the Solicitor General made the point at oral argument, the
statute must pose a “really difficult” or “very hard question of
statutory interpretation.” Tr. of Oral Arg. 50. And indeed, both
North Carolina and the Solicitor General agreed that such cases
will be “exceedingly rare.” Brief for Respondent 17; Tr. of Oral
Arg. 48.

															The Court’s analysis of Sergeant Darisse’s interpretation of the
North Carolina law at issue here appropriately reflects these
principles. As the Court explains, see ante , at
12–13 , the statute requires every car on the highway to have
“a stop lamp,” in the singular. N. C. Gen. Stat. Ann.
§20–129(g) (2007). But the statute goes on to state that a stop
lamp (or, in more modern terminology, brake light) “may be
incorporated into a unit with one or more other rear lamps,”
suggesting that a stop lamp itself qualifies as a rear lamp. Ibid. (emphasis added). And the statute further mandates
that every car have “ all originally equipped rear lamps
. . . in good working order.” §20–129(d) (emphasis
added). The North Carolina Court of Appeals dealt with the
statute’s conflicting signals in one way (deciding that a brake
light is not a rear lamp, and so only one needs to work);
but a court could easily take the officer’s view (deciding that a
brake light is a rear lamp, and if a car comes equipped with
more than one, as modern cars do, all must be in working order).
The critical point is that the statute poses a quite difficult
question of interpretation, and Sergeant Darisse’s judgment,
although overturned, had much to recommend it. I therefore agree
with the Court that the traffic stop he conducted did not violate
the Fourth Amendment. Notes 1 I note in addition, as does the
Court, that one kind of mistaken legal judgment—an error about the
contours of the Fourth Amendment itself—can never support a search
or seizure. See ante, at 10 (“An officer’s mistaken view
that” conduct does “ not give rise to” a Fourth Amendment
violation, “no matter how reasonable,” cannot change a court’s
“ultimate conclusion” that such a violation has occurred). As the
Solicitor General has explained, mistakes about the requirements of
the Fourth Amendment “violate the Fourth Amendment even when they
are reasonable.” Brief for United States as Amicus Curiae 30, n. 3; see Brief for Respondent 29 (stating the same
view). SUPREME COURT OF THE UNITED STATES

															_________________

															No. 13–604

															_________________

															NICHOLAS BRADY HEIEN, PETITIONER v. NORTH CAROLINA

															on writ of certiorari to the supreme court of north carolina

															[December 15, 2014]

															Justice Sotomayor, dissenting.

															The Court is, of course, correct that “ ‘the ultimate
touchstone of the Fourth Amendment is
“reasonableness.” ’ ” Riley v. California ,
573 U. S. ___, ___ (2014) (slip op., at 5). But this broad
statement simply sets the standard a court is to apply when it
conducts its inquiry into whether the Fourth Amendment has been
violated. It does not define the categories of inputs that courts
are to consider when assessing the reasonableness of a search or
seizure, each of which must be independently justified. What this
case requires us to decide is whether a police officer’s
understanding of the law is an input into the reasonableness
inquiry, or whether this inquiry instead takes the law as a given
and assesses an officer’s understanding of the facts against a
fixed legal yardstick.

															I would hold that determining whether a search or seizure is
reasonable requires evaluating an officer’s understanding of the
facts against the actual state of the law. I would accordingly
reverse the judgment of the North Carolina Supreme Court, and I
respectfully dissent from the Court’s contrary holding.

															I

															It is common ground that Heien was seized within the meaning of
the Fourth Amendment. Such a seizure comports with the Constitution
only if the officers had articulable and reasonable suspicion that
Heien was breaking the law. In Ornelas v. United
States ,517 U. S. 690,696 (1996), we explained that the
“principal components” of that determination “will be the events
which occurred leading up to the stop or search, and then the
decision whether these historical facts, viewed from the standpoint
of an objectively reasonable police officer, amount to reasonable
suspicion or to probable cause.” We described this kind of
determination as “a mixed question of law and fact”: “ ‘[T]he
issue is whether the facts satisfy the [relevant] statutory [or
constitutional] standard, or to put it another way, whether the
rule of law as applied to the established facts is or is not
violated.’ ” Id., at 696–697 (quoting Pullman-Standard v. Swint , 456 U. S 273, 289,
n. 19 (1982)). What matters, we said, are the facts as viewed
by an objectively reasonable officer, and the rule of law—not an
officer’s conception of the rule of law, and not even an officer’s
reasonable misunderstanding about the law, but the law.

															As a result, when we have talked about the leeway that officers
have in making probable-cause determinations, we have focused on
their assessments of facts. See, e.g., Terry v. Ohio ,392 U. S. 1–22 (1968) (framing the question as whether
the “facts” give rise to reasonable suspicion). We have conceded
that an arresting officer’s state of mind does not factor into the
probable-cause inquiry, “except for the facts that he
knows.” Devenpeck v. Alford ,543 U. S. 146,153
(2004) (emphasis added). And we have said that, to satisfy the
reasonableness requirement, “what is generally demanded of the many factual determinations that must regularly be made by agents
of the government . . . is not that they always be
correct, but that they always be reasonable.” Illinois v. Rodriguez ,497 U. S. 177,185 (1990) (emphasis added).
There is scarcely a peep in these cases to suggest that an
officer’s understanding or conception of anything other than the
facts is relevant.

															This framing of the reasonableness inquiry has not only been
focused on officers’ understanding of the facts, it has been
justified in large part based on the recognition that officers are
generally in a superior position, relative to courts, to evaluate
those facts and their significance as they unfold. In other words,
the leeway we afford officers’ factual assessments is rooted not
only in our recognition that police officers operating in the field
have to make quick decisions, see id., at 186, but also in
our understanding that police officers have the expertise to
“dra[w] inferences and mak[e] deductions . . . that might
well elude an untrained person.” United States v. Cortez ,449 U. S. 411,418 (1981). When officers evaluate
unfolding circumstances, they deploy that expertise to draw
“conclusions about human behavior” much in the way that “jurors
[do] as factfinders .” Ibid. (emphasis
added).

															The same cannot be said about legal exegesis. After all, the
meaning of the law is not probabilistic in the same way that
factual determinations are. Rather, “the notion that the law is
definite and knowable” sits at the foundation of our legal system. Cheek v. United States ,498 U. S. 192,199 (1991).
And it is courts, not officers, that are in the best position to
interpret the laws.

															Both our enunciation of the reasonableness inquiry and our
justification for it thus have always turned on an officer’s
factual conclusions and an officer’s expertise with respect to
those factual conclusions. Neither has hinted at taking into
account an officer’s understanding of the law, reasonable or
otherwise.

															II

															Departing from this tradition means further eroding the Fourth
Amendment’s protection of civil liberties in a context where that
protection has already been worn down. Traffic stops like those at
issue here can be “annoying, frightening, and perhaps humiliating.” Terry , 392 U. S., at 25; see Delaware v. Prouse ,440 U. S. 648,657 (1979). We have nevertheless
held that an officer’s subjective motivations do not render a
traffic stop unlawful. Whren v. United States ,517
U. S. 806 (1996). But we assumed in Whren that when an
officer acts on pretext, at least that pretext would be the
violation of an actual law. See id., at 810 (discussing the
three provisions of the District of Columbia traffic code that the
parties accepted the officer had probable cause to believe had been
vio-lated). Giving officers license to effect seizures so long as
they can attach to their reasonable view of the facts some
reasonable legal interpretation (or misinterpretation) that
suggests a law has been violated significantly expands this
authority. Cf. Barlow v. United States , 7 Pet. 404,
411 (1833) (Story, J.) (“There is scarcely any law which does not
admit of some ingenious doubt”). One wonders how a citizen seeking
to be law-abiding and to structure his or her behavior to avoid
these invasive, frightening, and humiliating encounters could do
so.

															In addition to these human consequences—including those for
communities and for their relationships with the police—permitting
mistakes of law to justify seizures has the perverse effect of
preventing or delaying the clarification of the law. Under such an
approach, courts need not interpret statutory language but can
instead simply decide whether an officer’s interpretation was
reasonable. Indeed, had this very case arisen after the North
Carolina Supreme Court announced its rule, the North Carolina Court
of Appeals would not have had the occasion to interpret the statute
at issue. Similarly, courts in the Eighth Circuit, which has been
the only Circuit to include police mistakes of law in the
reasonableness inquiry, have observed that they need not decide
interpretive questions under their approach. See, e.g., United States v. Rodriguez-Lopez , 444 F. 3d 1020,
1022–1023 (CA8 2006).[ 1 ] This result is bad for
citizens, who need to know their rights and responsibilities, and
it is bad for police, who would benefit from clearer direction. Cf. Camreta v. Greene , 563 U. S. ___, ___–___ (2011)
(slip op., at 10–11) (recognizing the importance of clarifying the
law).

															Of course, if the law enforcement system could not function
without permitting mistakes of law to justify seizures, one could
at least argue that permitting as much is a necessary evil. But I
have not seen any persuasive argument that law enforcement will be
unduly hampered by a rule that precludes consideration of mistakes
of law in the reasonableness inquiry. After all, there is no
indication that excluding an officer’s mistake of law from the
reasonableness inquiry has created a problem for law enforcement in
the overwhelming number of Circuits which have adopted that
approach. If an officer makes a stop in good faith but it turns out
that, as in this case, the officer was wrong about what the law
proscribed or required, I know of no penalty that the officer would
suffer. See 366 N. C. 271, 286–288, 737 S. E. 2d 351,
361–362 (2012) (Hudson, J., dissenting) (observing that “officers
(rightfully) face no punishment for a stop based on a mistake of
law”). Moreover, such an officer would likely have a defense to any
civil suit on the basis of qualified immunity. See Ashcroft v. al-Kidd , 563 U. S. ___, ___ (2011) (slip op., at 12)
(“Qualified immunity gives government officials breathing room to
make reasonable but mistaken judgments about open legal
questions”).

															Nor will it often be the case that any evidence that may be
seized during the stop will be suppressed, thanks to the exception
to the exclusionary rule for good-faith police errors. See, e.g., Davis v. United States , 564 U. S.
___, ___–___ (2011) (slip op., at 8–9). It is true that, unlike
most States, North Carolina does not provide a good-faith exception
as a matter of state law, see State v. Carter , 322
N. C. 709, 721–724, 370 S. E. 2d 553, 560–562 (1988), but
North Carolina recognizes that it may solve any remedial problems
it may perceive on its own, see id., at 724, 370 S. E.
2d, at 562; N. C. Gen. Stat. Ann. §15A–974 (2013) (statutory
good-faith exception).[ 2 ] More fundamentally,
that is a remedial concern, and the protections offered by the
Fourth Amendment are not meant to yield to accommodate remedial
concerns. Our jurisprudence draws a sharp “analytica[l]
distinct[ion]” between the existence of a Fourth Amendment
violation and the remedy for that violation. Davis , 564
U. S., at ___ (slip op., at 14).

															In short, there is nothing in our case law requiring us to hold
that a reasonable mistake of law can justify a seizure under the
Fourth Amendment, and quite a bit suggesting just the opposite. I
also see nothing to be gained from such a holding, and much to be
lost.

															III

															In reaching the contrary conclusion, the Court makes both
serious legal and practical errors. On the legal side, the Court
barely addresses Ornelas and the other cases that frame the
reasonableness inquiry around factual determinations. Instead, in
support of its conclusion that reasonable suspicion “arises from
the combination of an officer’s understanding of the facts and his understanding of the relevant law,” ante, at
6 (emphasis added), the Court first reaches to founding-era customs
statutes and cases applying those statutes. It concedes, however,
that these cases are “not directly on point” because they say
nothing about the scope of the Fourth Amendment and are instead
equivalents of our modern-day qualified immunity jurisprudence for
civil damages. Ante, at 7.

															The only link in the tenuous chain the Court constructs between
those cases and this one that has anything to say about the Fourth
Amendment is Brinegar v. United States ,338 U. S.
160 (1949). See ante , at 8. But all that our opinion in Brinegar actually says is that probable cause exists where
“ ‘the facts and circumstances within [the officers’]
knowledge and of which they had reasonably trustworthy information
[are] sufficient in themselves to warrant a man of reasonable
caution in the belief that’ an offense has been or is being
committed.” 338 U. S., at 175–176 (quoting Carroll v. United States ,267 U. S. 132,162 (1925)). It thus states
the uncontroversial proposition that the probable-cause inquiry
looks to the reasonableness of an officer’s understanding of the
facts. Indeed, Brinegar is an odd case for the Court to rely
on given that, like the cases I discussed above, it subsequently
emphasizes that “the mistakes must be those of reasonable men,
acting on facts leading sensibly to their conclusions of
probability.” 338 U. S., at 176 (emphasis added). Again,
reasonable understandings of the facts, not reasonable
understandings of what the law says.[ 3 ]

															Further, the Court looks to our decision in Michigan v. DeFillippo ,443 U. S. 31 (1979). This is a Fourth
Amendment case, but the Court’s reading of it imagines a holding
that is not rooted in the logic of the opinion. We held in DeFillippo that an officer had probable cause to support an
arrest even though the ordinance that had allegedly been violated
was later held by the Michigan Court of Appeals to be
unconstitutional. This was so, we explained, because the officer
conducted an arrest after having observed conduct that was
criminalized by a presumptively valid law at the time of that
conduct. See id ., at 37 (“At th[e] time [of the arrest], of
course, there was no controlling precedent that this ordinance was
or was not constitutional, and hence the conduct observed violated
a presumptively valid ordinance”). We noted that it would have been
wrong for that officer not to enforce the law in that sit-uation.
See id., at 38 (“Police are charged to enforce laws until
and unless they are declared unconstitutional. . . .
Society would be ill-served if its police officers tookit upon
themselves to determine which laws are and which are not
constitutionally entitled to enforcement”). DeFillippo thus did not involve any police “mistake” at
all. Rather, DeFillippo involved a police officer correctly
applying the law that was then in existence and that carried with
it a presumption of validity. Here, by contrast, police stopped
Heien on suspicion of committing an offense that never actually
existed. Given that our holding in DeFillippo relied so
squarely on the existence of a law criminalizing the defendant’s
conduct, and on the presumption of validity that attends actual
laws, it can hardly be said to control where, as here, no law ever
actually criminalized Heien’s conduct.

															On the practical side, the Court primarily contends that an
officer may confront “a situation in the field as to which the
application of a statute is unclear.” Ante , at 11. One is
left to wonder, however, why an innocent citizen should be made to
shoulder the burden of being seized whenever the law may be
susceptible to an interpretive question. Moreover, the Court fails
to reconcile its belief that the Fourth Amendment gives officers
leeway to address situations where the application of a criminal
statute may be unclear with our prior assumption that the Fourth
Amendment does not give officers such leeway where they rely on a
statute that authorizes police conduct that may violate the Fourth
Amendment. See Illinois v. Krull ,480 U. S. 340,
n. 12, 359 (1987). Nor does it engage with the analytic
consequences of North Carolina’s similar concession that it does
not mean to claim “that an officer’s mistaken understanding of the
Fourth Amendment itself can support a seizure if that understanding
was reason-able.” Brief for Respondent 29. It is not clear why an
officer’s mistaken understanding of other laws should be viewed
differently.

															While I appreciate that the Court has endeavored to set some
bounds on the types of mistakes of law that it thinks will qualify
as reasonable, and while I think that the set of reasonable
mistakes of law ought to be narrowly circumscribed if they are to
be countenanced at all, I am not at all convinced that the Court
has done so in a clear way. It seems to me that the difference
between qualified immunity’s reasonableness standard—which the
Court insists without elaboration does not apply here—and the
Court’s conception of reasonableness in this context—which remains
undefined—will prove murky in application. See ante, at 11.
I fear the Court’s unwillingness to sketch a fuller view of what
makes a mistake of law reasonable only presages the likely
difficulty that courts will have applying the Court’s decision in
this case.

															*  *  *

															To my mind, the more administrable approach—and the one more
consistent with our precedents and principles—would be to hold that
an officer’s mistake of law, no matter how reasonable, cannot
support the individualized suspicion necessary to justify a seizure
under the Fourth Amendment. I respectfully dissent. Notes 1 Every other Circuit to have squarely
addressed the question has held that police mistakes of law are not
a factor in the reasonableness inquiry. See United States v. Miller , 146 F. 3d 274, 279 (CA5 1998); United States v. McDonald , 453 F. 3d 958, 962 (CA7 2006); United
States v. King , 244 F. 3d 736, 741 (CA9 2001); United
States v. Nicholson , 721 F. 3d 1236, 1244 (CA10 2013); United States v. Chanthasouxat , 342 F. 3d 1271,
1279–1280 (CA11 2003). Five States have agreed. See Hilton v. State , 961 So. 2d 284, 298 (Fla. 2007); State v. Louwrens , 792 N. W. 2d 649, 652 (Iowa 2010); Martin v. Kansas Dept. of Revenue , 285 Kan. 625, 637–639, 176 P. 3d
938, 948 (2008); State v. Anderson , 683 N. W. 2d
818, 823–824 (Minn. 2004); State v. Lacasella , 313
Mont. 185, 193–195, 60 P. 3d 975, 981–982 (2002). 2 In addition to North Carolina, it
appears that 13 States do not provide a good-faith exception. See State v. Marsala , 216 Conn. 150, 151, 579 A. 2d
58, 59 (1990); Dorsey v. State , 761 A. 2d 807,
814 (Del. 2000); Gary v. State , 262 Ga. 573, 574–575,
422 S. E. 2d 426, 428 (1992); State v. Guzman ,
122 Idaho 981, 998, 842 P. 2d 660, 677 (1992); State v. Cline , 617 N. W. 2d 277, 283 (Iowa 2000), abrogated on
other grounds by State v. Turner , 630 N. W. 2d
601 (Iowa 2001); Commonwealth v. Upton , 394 Mass.
363, 370, n. 5, 476 N. E. 2d 548, 554, n. 5 (1985); State v. Canelo , 139 N. H. 376, 383, 653
A. 2d 1097, 1102 (1995); State v. Johnson , 168
N. J. 608, 622–623, 775 A. 2d 1273, 1281–1282 (2001); State v. Gutierrez , 116 N. M. 431, 432, 863
P. 2d 1052, 1053 (1993); People v. Bigelow , 66
N. Y. 2d 417, 427, 488 N. E. 2d 451, 457–458 (1985); Commonwealth v. Edmunds , 526 Pa. 374, 376, 586
A. 2d 887, 888 (1991); State v. Oakes , 157 Vt.
171, 173, 598 A. 2d 119, 121 (1991); State v. Afana , 169 Wash. 2d 169, 184, 233 P. 3d 879, 886
(2010);see also People v. Krueger , 175 Ill. 2d 60,
61, 76, 675 N. E. 2d 604, 606, 612 (1996) (limiting the
exception to situations where police have a warrant). 3 The Court in fact errs even earlier
in the chain when it represents United States v. Riddle , 5 Cranch 311 (1809), as containing some broad
proposition. Ante , at 6–7. As Justice Story explained in a
later case, the tolerance of mistakes of law in cases like Riddle was a result of the specific customs statute that
Congress had enacted. The Apollon , 9 Wheat. 362, 373 (1824)
(explaining that findings of probable cause “ha[d] never been
supposed to excuse any seizure, except where some statute
creates and defines the exemption from damages” (emphasis
added)).

Summary: The Supreme Court ruled that a police officer's reasonable mistake of law can still be considered reasonable suspicion to justify a traffic stop under the Fourth Amendment. In this case, the officer pulled over a vehicle for a broken brake light, but it was later determined that only one working brake light was required by law. The Court held that the officer's mistake about the brake-light law was reasonable, and therefore the traffic stop was lawful.