(Slip Opinion)              OCTOBER TERM, 2012                                       1

                                       Syllabus

         NOTE: Where it is feasible, a syllabus (headnote) will be released, as is
       being done in connection with this case, at the time the opinion is issued.
       The syllabus constitutes no part of the opinion of the Court but has been
       prepared by the Reporter of Decisions for the convenience of the reader.
       See United States v. Detroit Timber & Lumber Co., 200 U. S. 321, 337.


SUPREME COURT OF THE UNITED STATES

                                       Syllabus

                         FLORIDA v. JARDINES

        CERTIORARI TO THE SUPREME COURT OF FLORIDA

    No. 11–564.      Argued October 31, 2012—Decided March 26, 2013
Police took a drug-sniffing dog to Jardines’ front porch, where the dog
  gave a positive alert for narcotics. Based on the alert, the officers ob-
  tained a warrant for a search, which revealed marijuana plants;
  Jardines was charged with trafficking in cannabis. The Supreme
  Court of Florida approved the trial court’s decision to suppress the
  evidence, holding that the officers had engaged in a Fourth Amend-
  ment search unsupported by probable cause.
Held: The investigation of Jardines’ home was a “search” within the
 meaning of the Fourth Amendment. Pp. 3–10.
    (a) When “the Government obtains information by physically in-
 truding” on persons, houses, papers, or effects, “a ‘search’ within the
 original meaning of the Fourth Amendment” has “undoubtedly oc-
 curred.” United States v. Jones, 565 U. S. ___, ___, n. 3. Pp. 3–4.
    (b) At the Fourth Amendment’s “very core” stands “the right of a
 man to retreat into his own home and there be free from unreason-
 able governmental intrusion.” Silverman v. United States, 365 U. S.
 505, 511. The area “immediately surrounding and associated with
 the home”—the curtilage—is “part of the home itself for Fourth
 Amendment purposes.” Oliver v. United States, 466 U. S. 170, 180.
 The officers entered the curtilage here: The front porch is the classic
 exemplar of an area “to which the activity of home life extends.” Id.,
 at 182, n. 12. Pp. 4–5.
    (c) The officers’ entry was not explicitly or implicitly invited. Offi-
 cers need not “shield their eyes” when passing by a home “on public
 thoroughfares,” California v. Ciraolo, 476 U. S. 207, 213, but “no man
 can set his foot upon his neighbour’s close without his leave,” Entick
 v. Carrington, 2 Wils. K. B. 275, 291, 95 Eng. Rep. 807, 817. A police
 officer not armed with a warrant may approach a home in hopes of
 speaking to its occupants, because that is “no more than any private
2                          FLORIDA v. JARDINES

                                   Syllabus

    citizen might do.” Kentucky v. King, 563 U. S. ___, ___. But the scope
    of a license is limited not only to a particular area but also to a specif-
    ic purpose, and there is no customary invitation to enter the curtilage
    simply to conduct a search. Pp. 5–8.
       (d) It is unnecessary to decide whether the officers violated
    Jardines’ expectation of privacy under Katz v. United States, 389
    U. S. 347. Pp. 8–10.
73 So. 3d 34, affirmed.

   SCALIA, J., delivered the opinion of the Court, in which THOMAS,
GINSBURG, SOTOMAYOR, and KAGAN, JJ., joined. KAGAN, J., filed a con-
curring opinion, in which GINSBURG and SOTOMAYOR, JJ., joined. ALITO,
J., filed a dissenting opinion, in which ROBERTS, C. J., and KENNEDY
and BREYER, JJ., joined.
                       Cite as: 569 U. S. ____ (2013)                              1

                            Opinion of the Court

    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, Wash-
    ington, 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. 11–564
                                  _________________


    FLORIDA, PETITIONER v. JOELIS JARDINES
    ON WRIT OF CERTIORARI TO THE SUPREME COURT OF

                       FLORIDA

                               [March 26, 2013]


  JUSTICE SCALIA delivered the opinion of the Court.
  We consider whether using a drug-sniffing dog on a
homeowner’s porch to investigate the contents of the
home is a “search” within the meaning of the Fourth
Amendment.
                             I
  In 2006, Detective William Pedraja of the Miami-Dade
Police Department received an unverified tip that mari-
juana was being grown in the home of respondent Joelis
Jardines. One month later, the Department and the
Drug Enforcement Administration sent a joint surveillance
team to Jardines’ home. Detective Pedraja was part of
that team. He watched the home for fifteen minutes and
saw no vehicles in the driveway or activity around the
home, and could not see inside because the blinds were
drawn. Detective Pedraja then approached Jardines’
home accompanied by Detective Douglas Bartelt, a trained
canine handler who had just arrived at the scene with his
drug-sniffing dog. The dog was trained to detect the scent
of marijuana, cocaine, heroin, and several other drugs,
indicating the presence of any of these substances through
particular behavioral changes recognizable by his handler.
2                  FLORIDA v. JARDINES

                     Opinion of the Court

    Detective Bartelt had the dog on a six-foot leash, owing
in part to the dog’s “wild” nature, App. to Pet. for Cert. A–
35, and tendency to dart around erratically while search-
ing. As the dog approached Jardines’ front porch, he
apparently sensed one of the odors he had been trained to
detect, and began energetically exploring the area for the
strongest point source of that odor. As Detective Bartelt
explained, the dog “began tracking that airborne odor by
. . . tracking back and forth,” engaging in what is called
“bracketing,” “back and forth, back and forth.” Id., at A–
33 to A–34. Detective Bartelt gave the dog “the full six
feet of the leash plus whatever safe distance [he could]
give him” to do this—he testified that he needed to give
the dog “as much distance as I can.” Id., at A–35. And
Detective Pedraja stood back while this was occurring, so
that he would not “get knocked over” when the dog was
“spinning around trying to find” the source. Id., at A–38.
    After sniffing the base of the front door, the dog sat,
which is the trained behavior upon discovering the odor’s
strongest point. Detective Bartelt then pulled the dog
away from the door and returned to his vehicle. He left
the scene after informing Detective Pedraja that there had
been a positive alert for narcotics.
    On the basis of what he had learned at the home, De-
tective Pedraja applied for and received a warrant to
search the residence. When the warrant was executed later
that day, Jardines attempted to flee and was arrested; the
search revealed marijuana plants, and he was charged
with trafficking in cannabis.
    At trial, Jardines moved to suppress the marijuana
plants on the ground that the canine investigation was an
unreasonable search. The trial court granted the motion,
and the Florida Third District Court of Appeal reversed.
On a petition for discretionary review, the Florida Su-
preme Court quashed the decision of the Third District
Court of Appeal and approved the trial court’s decision to
                  Cite as: 569 U. S. ____ (2013)             3

                      Opinion of the Court

suppress, holding (as relevant here) that the use of the
trained narcotics dog to investigate Jardines’ home was
a Fourth Amendment search unsupported by probable
cause, rendering invalid the warrant based upon infor-
mation gathered in that search. 73 So. 3d 34 (2011).
  We granted certiorari, limited to the question of whether
the officers’ behavior was a search within the meaning of
the Fourth Amendment. 565 U. S. ___ (2012).
                               II
   The Fourth Amendment provides in relevant part that
the “right of the people to be secure in their persons, houses,
papers, and effects, against unreasonable searches and
seizures, shall not be violated.” The Amendment estab-
lishes a simple baseline, one that for much of our history
formed the exclusive basis for its protections: When “the
Government obtains information by physically intruding”
on persons, houses, papers, or effects, “a ‘search’ within
the original meaning of the Fourth Amendment” has “un-
doubtedly occurred.” United States v. Jones, 565 U. S.
___, ___, n. 3 (2012) (slip op., at 6, n. 3). By reason of
our decision in Katz v. United States, 389 U. S. 347
(1967), property rights “are not the sole measure of Fourth
Amendment violations,” Soldal v. Cook County, 506 U. S.
56, 64 (1992)—but though Katz may add to the baseline, it
does not subtract anything from the Amendment’s protec-
tions “when the Government does engage in [a] physi-
cal intrusion of a constitutionally protected area,” United
States v. Knotts, 460 U. S. 276, 286 (1983) (Brennan, J.,
concurring in the judgment).
   That principle renders this case a straightforward one.
The officers were gathering information in an area belong-
ing to Jardines and immediately surrounding his house—
in the curtilage of the house, which we have held enjoys
protection as part of the home itself. And they gathered
that information by physically entering and occupying the
4                  FLORIDA v. JARDINES

                     Opinion of the Court

area to engage in conduct not explicitly or implicitly per-
mitted by the homeowner.
                             A
   The Fourth Amendment “indicates with some precision
the places and things encompassed by its protections”:
persons, houses, papers, and effects. Oliver v. United
States, 466 U. S. 170, 176 (1984). The Fourth Amendment
does not, therefore, prevent all investigations conducted
on private property; for example, an officer may (subject to
Katz) gather information in what we have called “open
fields”—even if those fields are privately owned—because
such fields are not enumerated in the Amendment’s text.
Hester v. United States, 265 U. S. 57 (1924).
   But when it comes to the Fourth Amendment, the home
is first among equals. At the Amendment’s “very core”
stands “the right of a man to retreat into his own home
and there be free from unreasonable governmental in-
trusion.” Silverman v. United States, 365 U. S. 505, 511
(1961). This right would be of little practical value if the
State’s agents could stand in a home’s porch or side gar-
den and trawl for evidence with impunity; the right to
retreat would be significantly diminished if the police
could enter a man’s property to observe his repose from
just outside the front window.
   We therefore regard the area “immediately surrounding
and associated with the home”—what our cases call the
curtilage—as “part of the home itself for Fourth Amend-
ment purposes.” Oliver, supra, at 180. That principle has
ancient and durable roots. Just as the distinction between
the home and the open fields is “as old as the common
law,” Hester, supra, at 59, so too is the identity of home
and what Blackstone called the “curtilage or homestall,”
for the “house protects and privileges all its branches and
appurtenants.” 4 W. Blackstone, Commentaries on the
Laws of England 223, 225 (1769). This area around the
                    Cite as: 569 U. S. ____ (2013)                   5

                         Opinion of the Court

home is “intimately linked to the home, both physically
and psychologically,” and is where “privacy expectations
are most heightened.” California v. Ciraolo, 476 U. S. 207,
213 (1986).
   While the boundaries of the curtilage are generally
“clearly marked,” the “conception defining the curtilage” is
at any rate familiar enough that it is “easily understood
from our daily experience.” Oliver, 466 U. S., at 182, n. 12.
Here there is no doubt that the officers entered it: The
front porch is the classic exemplar of an area adjacent to
the home and “to which the activity of home life extends.”
Ibid.
                               B
   Since the officers’ investigation took place in a constitu-
tionally protected area, we turn to the question of whether
it was accomplished through an unlicensed physical in-
trusion.1 While law enforcement officers need not “shield
their eyes” when passing by the home “on public thorough-
fares,” Ciraolo, 476 U. S., at 213, an officer’s leave to
gather information is sharply circumscribed when he steps
off those thoroughfares and enters the Fourth Amend-
ment’s protected areas. In permitting, for example, visual
observation of the home from “public navigable airspace,”
we were careful to note that it was done “in a physically
nonintrusive manner.” Ibid. Entick v. Carrington, 2 Wils.
K. B. 275, 95 Eng. Rep. 807 (K. B. 1765), a case “undoubt-
edly familiar” to “every American statesman” at the time
of the Founding, Boyd v. United States, 116 U. S. 616, 626
——————
   1 At oral argument, the State and its amicus the Solicitor General

argued that Jardines conceded in the lower courts that the officers had
a right to be where they were. This misstates the record. Jardines
conceded nothing more than the unsurprising proposition that the of-
ficers could have lawfully approached his home to knock on the front
door in hopes of speaking with him. Of course, that is not what they
did.
6                       FLORIDA v. JARDINES

                           Opinion of the Court

(1886), states the general rule clearly: “[O]ur law holds the
property of every man so sacred, that no man can set his
foot upon his neighbour’s close without his leave.” 2 Wils.
K. B., at 291, 95 Eng. Rep., at 817. As it is undisputed
that the detectives had all four of their feet and all four of
their companion’s firmly planted on the constitutionally
protected extension of Jardines’ home, the only question is
whether he had given his leave (even implicitly) for them
to do so. He had not.
   “A license may be implied from the habits of the coun-
try,” notwithstanding the “strict rule of the English com-
mon law as to entry upon a close.” McKee v. Gratz, 260
U. S. 127, 136 (1922) (Holmes, J.). We have accordingly
recognized that “the knocker on the front door is treated
as an invitation or license to attempt an entry, justifying
ingress to the home by solicitors, hawkers and peddlers
of all kinds.” Breard v. Alexandria, 341 U. S. 622, 626
(1951). This implicit license typically permits the visitor
to approach the home by the front path, knock promptly,
wait briefly to be received, and then (absent invitation to
linger longer) leave. Complying with the terms of that
traditional invitation does not require fine-grained legal
knowledge; it is generally managed without incident by
the Nation’s Girl Scouts and trick-or-treaters.2 Thus, a
police officer not armed with a warrant may approach a
home and knock, precisely because that is “no more than
any private citizen might do.” Kentucky v. King, 563 U. S.
——————
    2 With this much, the dissent seems to agree—it would inquire into

“ ‘the appearance of things,’ ” post, at 5 (opinion of ALITO, J.), what is
“typica[l]” for a visitor, ibid., what might cause “alarm” to a “resident of
the premises,” ibid., what is “expected” of “ordinary visitors,” ibid., and
what would be expected from a “ ‘reasonably respectful citizen,’ ” post, at
7. These are good questions. But their answers are incompatible with
the dissent’s outcome, which is presumably why the dissent does not
even try to argue that it would be customary, usual, reasonable, re-
spectful, ordinary, typical, nonalarming, etc., for a stranger to explore
the curtilage of the home with trained drug dogs.
                     Cite as: 569 U. S. ____ (2013)                     7

                          Opinion of the Court

___, ___ (2011) (slip op., at 16).
   But introducing a trained police dog to explore the area
around the home in hopes of discovering incriminating
evidence is something else. There is no customary invita-
tion to do that. An invitation to engage in canine forensic
investigation assuredly does not inhere in the very act of
hanging a knocker.3 To find a visitor knocking on the door
is routine (even if sometimes unwelcome); to spot that
same visitor exploring the front path with a metal detec-
tor, or marching his bloodhound into the garden before
saying hello and asking permission, would inspire most
of us to—well, call the police. The scope of a license—
express or implied—is limited not only to a particular area
but also to a specific purpose. Consent at a traffic stop to
an officer’s checking out an anonymous tip that there is a
body in the trunk does not permit the officer to rummage
through the trunk for narcotics. Here, the background
social norms that invite a visitor to the front door do not
invite him there to conduct a search.4
——————
   3 The dissent insists that our argument must rest upon “the particu-

lar instrument that Detective Bartelt used to detect the odor of mari-
juana”—the dog. Post, at 8. It is not the dog that is the problem, but the
behavior that here involved use of the dog. We think a typical person
would find it “ ‘a cause for great alarm’ ” (the kind of reaction the dis-
sent quite rightly relies upon to justify its no-night-visits rule, post,
at 5) to find a stranger snooping about his front porch with or without
a dog. The dissent would let the police do whatever they want by way
of gathering evidence so long as they stay on the base-path, to use a
baseball analogy—so long as they “stick to the path that is typically
used to approach a front door, such as a paved walkway.” Ibid. From
that vantage point they can presumably peer into the house through
binoculars with impunity. That is not the law, as even the State con-
cedes. See Tr. of Oral Arg. 6.
   4 The dissent argues, citing King, that “gathering evidence—even

damning evidence—is a lawful activity that falls within the scope of the
license to approach.” Post, at 7. That is a false generalization. What
King establishes is that it is not a Fourth Amendment search to ap-
proach the home in order to speak with the occupant, because all are
8                      FLORIDA v. JARDINES

                         Opinion of the Court

  The State points to our decisions holding that the sub-
jective intent of the officer is irrelevant. See Ashcroft v.
al-Kidd, 563 U. S. ___ (2011); Whren v. United States, 517
U. S. 806 (1996). But those cases merely hold that a stop
or search that is objectively reasonable is not vitiated by
the fact that the officer’s real reason for making the stop
or search has nothing to do with the validating reason.
Thus, the defendant will not be heard to complain that
although he was speeding the officer’s real reason for the
stop was racial harassment. See id., at 810, 813. Here,
however, the question before the court is precisely whether
the officer’s conduct was an objectively reasonable search.
As we have described, that depends upon whether the
officers had an implied license to enter the porch, which in
turn depends upon the purpose for which they entered.
Here, their behavior objectively reveals a purpose to con-
duct a search, which is not what anyone would think he
had license to do.
                              III
   The State argues that investigation by a forensic narcot-
ics dog by definition cannot implicate any legitimate pri-
vacy interest. The State cites for authority our decisions
in United States v. Place, 462 U. S. 696 (1983), United
States v. Jacobsen, 466 U. S. 109 (1984), and Illinois v.
Caballes, 543 U. S. 405 (2005), which held, respectively,
that canine inspection of luggage in an airport, chemical
testing of a substance that had fallen from a parcel in
transit, and canine inspection of an automobile during a
lawful traffic stop, do not violate the “reasonable expecta-
tion of privacy” described in Katz.

—————— 

invited to do that. The mere “purpose of discovering information,” post,
at 8, in the course of engaging in that permitted conduct does not cause
it to violate the Fourth Amendment. But no one is impliedly invited to
enter the protected premises of the home in order to do nothing but
conduct a search.
                 Cite as: 569 U. S. ____ (2013)            9

                     Opinion of the Court

   Just last Term, we considered an argument much like
this. Jones held that tracking an automobile’s where-
abouts using a physically-mounted GPS receiver is a Fourth
Amendment search. The Government argued that the
Katz standard “show[ed] that no search occurred,” as the
defendant had “no ‘reasonable expectation of privacy’ ” in
his whereabouts on the public roads, Jones, 565 U. S., at
___ (slip op., at 5)—a proposition with at least as much
support in our case law as the one the State marshals
here. See, e.g., United States v. Knotts, 460 U. S. 276, 278
(1983). But because the GPS receiver had been physically
mounted on the defendant’s automobile (thus intruding on
his “effects”), we held that tracking the vehicle’s move-
ments was a search: a person’s “Fourth Amendment rights
do not rise or fall with the Katz formulation.” Jones,
supra, at ___ (slip op., at 5). The Katz reasonable-
expectations test “has been added to, not substituted
for,” the traditional property-based understanding of the
Fourth Amendment, and so is unnecessary to consider
when the government gains evidence by physically intrud-
ing on constitutionally protected areas. Jones, supra, at
___ (slip op., at 8).
   Thus, we need not decide whether the officers’ investiga-
tion of Jardines’ home violated his expectation of privacy
under Katz. One virtue of the Fourth Amendment’s
property-rights baseline is that it keeps easy cases easy.
That the officers learned what they learned only by physi-
cally intruding on Jardines’ property to gather evidence is
enough to establish that a search occurred.
   For a related reason we find irrelevant the State’s ar-
gument (echoed by the dissent) that forensic dogs have
been commonly used by police for centuries. This argu-
ment is apparently directed to our holding in Kyllo v.
United States, 533 U. S. 27 (2001), that surveillance of
the home is a search where “the Government uses a device
that is not in general public use” to “explore details of the
10                 FLORIDA v. JARDINES

                     Opinion of the Court

home that would previously have been unknowable with-
out physical intrusion.” Id., at 40 (emphasis added). But
the implication of that statement (inclusio unius est exclu-
sio alterius) is that when the government uses a physical
intrusion to explore details of the home (including its
curtilage), the antiquity of the tools that they bring along
is irrelevant.
                      *    *    *
   The government’s use of trained police dogs to inves-
tigate the home and its immediate surroundings is a
“search” within the meaning of the Fourth Amendment.
The judgment of the Supreme Court of Florida is therefore
affirmed.
                                         It is so ordered.
                 Cite as: 569 U. S. ____ (2013)           1

                     KAGAN, J., concurring

SUPREME COURT OF THE UNITED STATES
                         _________________

                          No. 11–564
                         _________________


    FLORIDA, PETITIONER v. JOELIS JARDINES
    ON WRIT OF CERTIORARI TO THE SUPREME COURT OF

                       FLORIDA

                       [March 26, 2013]


   JUSTICE KAGAN, with whom JUSTICE GINSBURG and
JUSTICE SOTOMAYOR join, concurring.
   For me, a simple analogy clinches this case—and does
so on privacy as well as property grounds. A stranger
comes to the front door of your home carrying super-high-
powered binoculars. See ante, at 7, n. 3. He doesn’t knock
or say hello. Instead, he stands on the porch and uses the
binoculars to peer through your windows, into your home’s
furthest corners. It doesn’t take long (the binoculars are
really very fine): In just a couple of minutes, his uncom-
mon behavior allows him to learn details of your life you
disclose to no one. Has your “visitor” trespassed on your
property, exceeding the license you have granted to mem-
bers of the public to, say, drop off the mail or distribute
campaign flyers? Yes, he has. And has he also invaded
your “reasonable expectation of privacy,” by nosing into
intimacies you sensibly thought protected from disclosure?
Katz v. United States, 389 U. S. 347, 360 (1967) (Harlan,
J., concurring). Yes, of course, he has done that too.
   That case is this case in every way that matters. Here,
police officers came to Joelis Jardines’ door with a super-
sensitive instrument, which they deployed to detect things
inside that they could not perceive unassisted. The equip-
ment they used was animal, not mineral. But contra the
dissent, see post, at 2 (opinion of ALITO, J.) (noting the
ubiquity of dogs in American households), that is of no
2                   FLORIDA v. JARDINES

                     KAGAN, J., concurring

significance in determining whether a search occurred.
Detective Bartelt’s dog was not your neighbor’s pet, come
to your porch on a leisurely stroll. As this Court discussed
earlier this Term, drug-detection dogs are highly trained
tools of law enforcement, geared to respond in distinctive
ways to specific scents so as to convey clear and reliable
information to their human partners. See Florida v.
Harris, 568 U. S. ___ (2013) (slip op. at 2–3, 7–8). They
are to the poodle down the street as high-powered binocu-
lars are to a piece of plain glass. Like the binoculars, a
drug-detection dog is a specialized device for discovering
objects not in plain view (or plain smell). And as in the
hypothetical above, that device was aimed here at a
home—the most private and inviolate (or so we expect) of
all the places and things the Fourth Amendment protects.
Was this activity a trespass? Yes, as the Court holds to-
day. Was it also an invasion of privacy? Yes, that as well.
   The Court today treats this case under a property ru-
bric; I write separately to note that I could just as happily
have decided it by looking to Jardines’ privacy interests. A
decision along those lines would have looked . . . well,
much like this one. It would have talked about “ ‘the right
of a man to retreat into his own home and there be free
from unreasonable governmental intrusion.’ ” Ante, at 4
(quoting Silverman v. United States, 365 U. S. 505, 511
(1961)). It would have insisted on maintaining the “prac-
tical value” of that right by preventing police officers from
standing in an adjacent space and “trawl[ing] for evidence
with impunity.” Ante, at 4. It would have explained that
“ ‘privacy expectations are most heightened’ ” in the home
and the surrounding area. Ante, at 4–5 (quoting Califor-
nia v. Ciraolo, 476 U. S. 207, 213 (1986)). And it would
have determined that police officers invade those shared
expectations when they use trained canine assistants to
reveal within the confines of a home what they could not
otherwise have found there. See ante, at 6–7, and nn. 2–3.
                      Cite as: 569 U. S. ____ (2013)                      3

                          KAGAN, J., concurring

  It is not surprising that in a case involving a search of a
home, property concepts and privacy concepts should so
align. The law of property “naturally enough influence[s]”
our “shared social expectations” of what places should be
free from governmental incursions. Georgia v. Randolph,
547 U. S. 103, 111 (2006); see Rakas v. Illinois, 439 U. S.
128, 143, n. 12 (1978). And so the sentiment “my home is
my own,” while originating in property law, now also
denotes a common understanding—extending even beyond
that law’s formal protections—about an especially private
sphere. Jardines’ home was his property; it was also his
most intimate and familiar space. The analysis proceed-
ing from each of those facts, as today’s decision reveals,
runs mostly along the same path.
  I can think of only one divergence: If we had decided
this case on privacy grounds, we would have realized that
Kyllo v. United States, 533 U. S. 27 (2001), already re-
solved it.1 The Kyllo Court held that police officers con-
ducted a search when they used a thermal-imaging device
to detect heat emanating from a private home, even
though they committed no trespass. Highlighting our
intention to draw both a “firm” and a “bright” line at “the
entrance to the house,” id., at 40, we announced the fol-
lowing rule:
     “Where, as here, the Government uses a device that is
     not in general public use, to explore details of the
     home that would previously have been unknowable
——————
   1 The dissent claims, alternatively, that Illinois v. Caballes, 543 U. S.

405, 409–410 (2005), controls this case (or nearly does). See post, at 9,
11. But Caballes concerned a drug-detection dog’s sniff of an automo-
bile during a traffic stop. See also Florida v. Harris, 568 U. S. ___
(2013). And we have held, over and over again, that people’s expecta-
tions of privacy are much lower in their cars than in their homes. See,
e.g., Arizona v. Gant, 556 U. S. 332, 345 (2009); Wyoming v. Houghton,
526 U. S. 295, 303 (1999); New York v. Class, 475 U. S. 106, 115 (1986);
Cardwell v. Lewis, 417 U. S. 583, 590–591 (1974) (plurality opinion).
4                      FLORIDA v. JARDINES

                         KAGAN, J., concurring

       without physical intrusion, the surveillance is a
       ‘search’ and is presumptively unreasonable without a
       warrant.” Ibid.
That “firm” and “bright” rule governs this case: The police
officers here conducted a search because they used a
“device . . . not in general public use” (a trained drug-
detection dog) to “explore details of the home” (the pres-
ence of certain substances) that they would not otherwise
have discovered without entering the premises.
   And again, the dissent’s argument that the device is just
a dog cannot change the equation. As Kyllo made clear,
the “sense-enhancing” tool at issue may be “crude” or
“sophisticated,” may be old or new (drug-detection dogs
actually go back not “12,000 years” or “centuries,” post, at
2, 8, 12, but only a few decades), may be either smaller or
bigger than a breadbox; still, “at least where (as here)” the
device is not “in general public use,” training it on a home
violates our “minimal expectation of privacy”—an expecta-
tion “that exists, and that is acknowledged to be reasona-
ble.” 533 U. S., at 34, 36.2 That does not mean the device
——————
    2 The
        dissent’s other principal reason for concluding that no violation
of privacy occurred in this case—that police officers themselves might
detect an aroma wafting from a house—works no better. If officers can
smell drugs coming from a house, they can use that information; a
human sniff is not a search, we can all agree. But it does not follow
that a person loses his expectation of privacy in the many scents within
his home that (his own nose capably tells him) are not usually detecti-
ble by humans standing outside. And indeed, Kyllo already decided as
much. In response to an identical argument from the dissent in that
case, see 533 U. S., at 43 (Stevens, J., dissenting) (noting that humans
can sometimes detect “heat emanating from a building”), the Kyllo
Court stated: “The dissent’s comparison of the thermal imaging to
various circumstances in which outside observers might be able to
perceive, without technology, the heat of the home . . . is quite irrele-
vant. The fact that equivalent information could sometimes be ob-
tained by other means does not make lawful the use of means that
violate the Fourth Amendment. . . . In any event, [at the time in
question,] no outside observer could have discerned the relative heat of
                     Cite as: 569 U. S. ____ (2013)          5

                         KAGAN, J., concurring

is off-limits, as the dissent implies, see post, at 11–12; it
just means police officers cannot use it to examine a home
without a warrant or exigent circumstance. See Brigham
City v. Stuart, 547 U. S. 398, 403–404 (2006) (describing
exigencies allowing the warrantless search of a home).
   With these further thoughts, suggesting that a focus on
Jardines’ privacy interests would make an “easy cas[e]
easy” twice over, ante, at 9, I join the Court’s opinion in
full.




—————— 

Kyllo’s home without thermal imaging.” Id., at 35, n. 2. 

                 Cite as: 569 U. S. ____ (2013)           1

                     ALITO, J., dissenting

SUPREME COURT OF THE UNITED STATES
                         _________________

                          No. 11–564
                         _________________


    FLORIDA, PETITIONER v. JOELIS JARDINES
    ON WRIT OF CERTIORARI TO THE SUPREME COURT OF

                       FLORIDA

                       [March 26, 2013]


  JUSTICE ALITO, with whom THE CHIEF JUSTICE,         JUS-
TICE KENNEDY, and JUSTICE BREYER join, dissenting.
   The Court’s decision in this important Fourth Amend-
ment case is based on a putative rule of trespass law that
is nowhere to be found in the annals of Anglo-American
jurisprudence.
   The law of trespass generally gives members of the
public a license to use a walkway to approach the front
door of a house and to remain there for a brief time. This
license is not limited to persons who intend to speak to an
occupant or who actually do so. (Mail carriers and persons
delivering packages and flyers are examples of individuals
who may lawfully approach a front door without intending
to converse.) Nor is the license restricted to categories
of visitors whom an occupant of the dwelling is likely to
welcome; as the Court acknowledges, this license applies
even to “solicitors, hawkers and peddlers of all kinds.”
Ante, at 6 (internal quotation marks omitted). And the
license even extends to police officers who wish to gather
evidence against an occupant (by asking potentially in-
criminating questions).
   According to the Court, however, the police officer in
this case, Detective Bartelt, committed a trespass because
he was accompanied during his otherwise lawful visit to
the front door of respondent’s house by his dog, Franky.
Where is the authority evidencing such a rule? Dogs have
2                     FLORIDA v. JARDINES

                        ALITO, J., dissenting

been domesticated for about 12,000 years;1 they were
ubiquitous in both this country and Britain at the time of
the adoption of the Fourth Amendment;2 and their acute
sense of smell has been used in law enforcement for centu-
ries.3 Yet the Court has been unable to find a single
case—from the United States or any other common-law
nation—that supports the rule on which its decision is
based. Thus, trespass law provides no support for the
Court’s holding today.
  The Court’s decision is also inconsistent with the
reasonable-expectations-of-privacy test that the Court
adopted in Katz v. United States, 389 U. S. 347 (1967). A
reasonable person understands that odors emanating from a
house may be detected from locations that are open to the
public, and a reasonable person will not count on the
strength of those odors remaining within the range that,
while detectible by a dog, cannot be smelled by a human.
  For these reasons, I would hold that no search within
the meaning of the Fourth Amendment took place in this
case, and I would reverse the decision below.
                             I
   The opinion of the Court may leave a reader with the
mistaken impression that Detective Bartelt and Franky
remained on respondent’s property for a prolonged period
of time and conducted a far-flung exploration of the front
yard. See ante, at 4 (“trawl for evidence with impunity”),
7 (“marching his bloodhound into the garden”). But that
is not what happened.
   Detective Bartelt and Franky approached the front door
via the driveway and a paved path—the route that any
——————
  1 See, e.g., Sloane, Dogs in War, Police Work and on Patrol, 46 J.

Crim. L., C. & P. S. 385 (1955–1956) (hereinafter Sloane).
  2 M. Derr, A Dog’s History of America 68–92 (2004); K. Olsen, Daily

Life in 18th-Century England 32–33 (1999).
  3 Sloane 388–389.
                    Cite as: 569 U. S. ____ (2013)                   3

                         ALITO, J., dissenting

visitor would customarily use4—and Franky was on the
kind of leash that any dog owner might employ.5 As
Franky approached the door, he started to track an air-
borne odor. He held his head high and began “bracketing”
the area (pacing back and forth) in order to determine the
strongest source of the smell. App. 95–96. Detective
Bartelt knew “the minute [he] observed” this behavior that
Franky had detected drugs. Id., at 95. Upon locating the
odor’s strongest source, Franky sat at the base of the front
door, and at this point, Detective Bartelt and Franky im-
mediately returned to their patrol car. Id., at 98.
  A critical fact that the Court omits is that, as respond-
ent’s counsel explained at oral argument, this entire
process—walking down the driveway and front path to the
front door, waiting for Franky to find the strongest source
of the odor, and walking back to the car—took approxi-
mately a minute or two. Tr. of Oral Arg. 57–58. Thus, the
amount of time that Franky and the detective remained
at the front porch was even less. The Court also fails to
mention that, while Detective Bartelt apparently did not
personally smell the odor of marijuana coming from the
house, another officer who subsequently stood on the front
porch, Detective Pedraja, did notice that smell and was
able to identify it. App. 81.
                             II
  The Court concludes that the conduct in this case was a
search because Detective Bartelt exceeded the boundaries
of the license to approach the house that is recognized by

——————
  4 See App. 94; App. to Brief for Respondent 1A (depiction of respond-

ent’s home).
  5 The Court notes that Franky was on a 6-foot leash, but such a

leash is standard equipment for ordinary dog owners. See, e.g.,
J. Stregowski, Four Dog Leash Varieties, http://dogs.about.com/od/
toyssupplies/tp/Dog-Leashes.htm (all Internet materials as visited Mar.
21, 2013, and available in Clerk of Court’s case file).
4                  FLORIDA v. JARDINES

                     ALITO, J., dissenting

the law of trespass, but the Court’s interpretation of the
scope of that license is unfounded.
                              A
   It is said that members of the public may lawfully pro-
ceed along a walkway leading to the front door of a house
because custom grants them a license to do so. Breard v.
Alexandria, 341 U. S. 622, 626 (1951); Lakin v. Ames, 64
Mass. 198, 220 (1852); J. Bishop, Commentaries on the
Non-Contract Law §823, p. 378 (1889). This rule encom-
passes categories of visitors whom most homeowners
almost certainly wish to allow to approach their front
doors—friends, relatives, mail carriers, persons making
deliveries. But it also reaches categories of visitors who
are less universally welcome—“solicitors,” “hawkers,”
“peddlers,” and the like. The law might attempt to draw
fine lines between categories of welcome and unwelcome
visitors, distinguishing, for example, between tolerable
and intolerable door-to-door peddlers (Girl Scouts selling
cookies versus adults selling aluminum siding) or be-
tween police officers on agreeable and disagreeable mis-
sions (gathering information about a bothersome neighbor
versus asking potentially incriminating questions). But
the law of trespass has not attempted such a difficult
taxonomy. See Desnick v. American Broadcasting Cos., 44
F. 3d 1345, 1351 (CA7 1995) (“[C]onsent to an entry is
often given legal effect even though the entrant has inten-
tions that if known to the owner of the property would
cause him for perfectly understandable and generally
ethical or at least lawful reasons to revoke his consent”);
cf. Skinner v. Ogallala Public School Dist., 262 Neb. 387,
402, 631 N. W. 2d 510, 525 (2001) (“[I]n order to determine
if a business invitation is implied, the inquiry is not a
subjective assessment of why the visitor chose to visit the
premises in a particular instance”); Crown Cork & Seal
Co. v. Kane, 213 Md. 152, 159, 131 A. 2d 470, 473–474
                 Cite as: 569 U. S. ____ (2013)            5

                     ALITO, J., dissenting

(1957) (noting that “there are many cases in which an
invitation has been implied from circumstances, such as
custom,” and that this test is “objective in that it stresses
custom and the appearance of things” as opposed to “the
undisclosed intention of the visitor”).
   Of course, this license has certain spatial and temporal
limits. A visitor must stick to the path that is typically
used to approach a front door, such as a paved walkway.
A visitor cannot traipse through the garden, meander into
the backyard, or take other circuitous detours that veer
from the pathway that a visitor would customarily use.
See, e.g., Robinson v. Virginia, 47 Va. App. 533, 549–550,
625 S. E. 2d 651, 659 (2006) (en banc); United States v.
Wells, 648 F. 3d 671, 679–680 (CA8 2011) (police exceeded
scope of their implied invitation when they bypassed the
front door and proceeded directly to the back yard); State
v. Harris, 919 S. W. 2d 619, 624 (Tenn. Crim. App. 1995)
(“Any substantial and unreasonable departure from an
area where the public is impliedly invited exceeds the
scope of the implied invitation . . . ” (internal quotation
marks and brackets omitted)); 1 W. LaFave, Search and
Seizure §2.3(c), p. 578 (2004) (hereinafter LaFave); id.,
§2.3(f), at 600–603 (“[W]hen the police come on to private
property to conduct an investigation or for some other
legitimate purpose and restrict their movements to places
visitors could be expected to go (e.g., walkways, drive-
ways, porches), observations made from such vantage points
are not covered by the Fourth Amendment” (footnotes
omitted)).
   Nor, as a general matter, may a visitor come to the front
door in the middle of the night without an express invita-
tion. See State v. Cada, 129 Idaho 224, 233, 923 P. 2d 469,
478 (App. 1996) (“Furtive intrusion late at night or in the
predawn hours is not conduct that is expected from ordi-
nary visitors. Indeed, if observed by a resident of the
premises, it could be a cause for great alarm”).
6                  FLORIDA v. JARDINES

                     ALITO, J., dissenting

   Similarly, a visitor may not linger at the front door for
an extended period. See 9 So. 3d 1, 11 (Fla. App. 2008)
(case below) (Cope, J., concurring in part and dissenting in
part) (“[T]here is no such thing as squatter’s rights on a
front porch. A stranger may not plop down uninvited to
spend the afternoon in the front porch rocking chair, or
throw down a sleeping bag to spend the night, or lurk on
the front porch, looking in the windows”). The license is
limited to the amount of time it would customarily take to
approach the door, pause long enough to see if someone is
home, and (if not expressly invited to stay longer), leave.
   As I understand the law of trespass and the scope of the
implied license, a visitor who adheres to these limitations
is not necessarily required to ring the doorbell, knock on
the door, or attempt to speak with an occupant. For ex-
ample, mail carriers, persons making deliveries, and in-
dividuals distributing flyers may leave the items they
are carrying and depart without making any attempt to
converse. A pedestrian or motorist looking for a particular
address may walk up to a front door in order to check a
house number that is hard to see from the sidewalk or
road. A neighbor who knows that the residents are away
may approach the door to retrieve an accumulation of
newspapers that might signal to a potential burglar that
the house is unoccupied.
   As the majority acknowledges, this implied license to
approach the front door extends to the police. See ante, at
6. As we recognized in Kentucky v. King, 563 U. S. ___
(2011), police officers do not engage in a search when they
approach the front door of a residence and seek to engage
in what is termed a “knock and talk,” i.e., knocking on the
door and seeking to speak to an occupant for the purpose
of gathering evidence. See id., at ___ (slip op., at 16)
(“When law enforcement officers who are not armed with a
warrant knock on a door, they do no more than any pri-
vate citizen might do”). See also 1 LaFave §2.3(e), at 592
                  Cite as: 569 U. S. ____ (2013)             7

                      ALITO, J., dissenting

(“It is not objectionable for an officer to come upon that
part of the property which has been opened to public
common use” (internal quotation marks omitted)). Even
when the objective of a “knock and talk” is to obtain evi-
dence that will lead to the homeowner’s arrest and prose-
cution, the license to approach still applies. In other
words, gathering evidence—even damning evidence—is a
lawful activity that falls within the scope of the license to
approach. And when officers walk up to the front door of a
house, they are permitted to see, hear, and smell whatever
can be detected from a lawful vantage point. California v.
Ciraolo, 476 U. S. 207, 213 (1986) (“The Fourth Amend-
ment protection of the home has never been extended to
require law enforcement officers to shield their eyes when
passing by a home on public thoroughfares”); Cada, supra,
at 232, 923 P. 2d, at 477 (“[P]olice officers restricting their
activity to [areas to which the public is impliedly invited]
are permitted the same intrusion and the same level
of observation as would be expected from a reasonably
respectful citizen” (internal quotation marks omitted)); 1
LaFave §§2.2(a), 2.3(c), at 450–452, 572–577.
                             B
  Detective Bartelt did not exceed the scope of the license
to approach respondent’s front door. He adhered to the
customary path; he did not approach in the middle of the
night; and he remained at the front door for only a very
short period (less than a minute or two).
  The Court concludes that Detective Bartelt went too far
because he had the “objectiv[e] . . . purpose to conduct a
search.” Ante, at 8 (emphasis added). What this means, I
take it, is that anyone aware of what Detective Bartelt did
would infer that his subjective purpose was to gather
evidence. But if this is the Court’s point, then a standard
“knock and talk” and most other police visits would like-
wise constitute searches. With the exception of visits to
8                   FLORIDA v. JARDINES

                      ALITO, J., dissenting

serve warrants or civil process, police almost always ap-
proach homes with a purpose of discovering information.
That is certainly the objective of a “knock and talk.” The
Court offers no meaningful way of distinguishing the
“objective purpose” of a “knock and talk” from the “objec-
tive purpose” of Detective Bartelt’s conduct here.
   The Court contends that a “knock and talk” is different
because it involves talking, and “all are invited” to do that.
Ante, at 7–8, n. 4 (emphasis deleted). But a police officer
who approaches the front door of a house in accordance
with the limitations already discussed may gather evi-
dence by means other than talking. The officer may ob-
serve items in plain view and smell odors coming from the
house. Ciraolo, supra, at 213; Cada, 129 Idaho, at 232,
923 P. 2d, at 477; 1 LaFave §§2.2(a), 2.3(c), at 450–452,
572–577. So the Court’s “objective purpose” argument
cannot stand.
   What the Court must fall back on, then, is the particular
instrument that Detective Bartelt used to detect the odor
of marijuana, namely, his dog. But in the entire body of
common-law decisions, the Court has not found a single
case holding that a visitor to the front door of a home
commits a trespass if the visitor is accompanied by a dog
on a leash. On the contrary, the common law allowed even
unleashed dogs to wander on private property without
committing a trespass. G. Williams, Liability for Animals
136–146 (1939); J. Ingham, A Treatise on Property in
Animals Wild and Domestic and the Rights and Respon-
sibilities Arising Therefrom 277–278 (1900).           Cf. B.
Markesinis & S. Deakin, Tort Law 511 (4th ed. 1999).
   The Court responds that “[i]t is not the dog that is the
problem, but the behavior that here involved use of the
dog.” Ante, at 7, n. 3. But where is the support in the law
of trespass for this proposition? Dogs’ keen sense of smell
has been used in law enforcement for centuries. The
antiquity of this practice is evidenced by a Scottish law
                  Cite as: 569 U. S. ____ (2013)            9

                      ALITO, J., dissenting

from 1318 that made it a crime to “disturb a tracking dog
or the men coming with it for pursuing thieves or seizing
malefactors.” K. Brown et al., The Records of the Parlia-
ments of Scotland to 1707, (St Andrews, 2007–2013),
online at http://www.rps.ac.uk/mss/1318/9. If bringing a
tracking dog to the front door of a home constituted a
trespass, one would expect at least one case to have arisen
during the past 800 years. But the Court has found none.
  For these reasons, the real law of trespass provides no
support for the Court’s holding today. While the Court
claims that its reasoning has “ancient and durable
roots,” ante, at 4, its trespass rule is really a newly struck
counterfeit.
                              III
   The concurring opinion attempts to provide an alterna-
tive ground for today’s decision, namely, that Detective
Bartelt’s conduct violated respondent’s reasonable expec-
tations of privacy. But we have already rejected a very
similar, if not identical argument, see Illinois v. Caballes,
543 U. S. 405, 409–410 (2005), and in any event I see no
basis for concluding that the occupants of a dwelling have
a reasonable expectation of privacy in odors that emanate
from the dwelling and reach spots where members of the
public may lawfully stand.
   It is clear that the occupant of a house has no reasona-
ble expectation of privacy with respect to odors that can be
smelled by human beings who are standing in such places.
See United States v. Johns, 469 U. S. 478, 482 (1985)
(“After the officers came closer and detected the distinct
odor of marihuana, they had probable cause to believe
that the vehicles contained contraband”); United States
v. Ventresca, 380 U. S. 102, 111 (1965) (scent of ferment-
ing mash supported probable cause for warrant); United
States v. Johnston, 497 F. 2d 397, 398 (CA9 1974) (there
is no “reasonable expectation of privacy from drug agents
10                    FLORIDA v. JARDINES

                         ALITO, J., dissenting

with inquisitive nostrils”). And I would not draw a line
between odors that can be smelled by humans and those
that are detectible only by dogs.
   Consider the situation from the point of view of the
occupant of a building in which marijuana is grown or
methamphetamine is manufactured. Would such an oc-
cupant reason as follows? “I know that odors may ema-
nate from my building and that atmospheric conditions,
such as the force and direction of the wind, may affect the
strength of those odors when they reach a spot where
members of the public may lawfully stand. I also know
that some people have a much more acute sense of smell
than others,6 and I have no idea who might be standing in
one of the spots in question when the odors from my house
reach that location. In addition, I know that odors coming
from my building, when they reach these locations, may be
strong enough to be detected by a dog. But I am confident
that they will be so faint that they cannot be smelled by
any human being.” Such a finely tuned expectation would
be entirely unrealistic, and I see no evidence that society
is prepared to recognize it as reasonable.
   In an attempt to show that respondent had a reasonable
expectation of privacy in the odor of marijuana wafting
from his house, the concurrence argues that this case is
just like Kyllo v. United States, 533 U. S. 27 (2001), which
held that police officers conducted a search when they
used a thermal imaging device to detect heat emanating
from a house. Ante, at 3–4 (opinion of KAGAN, J.). This
Court, however, has already rejected the argument that
——————
  6 Some humans naturally have a much more acute sense of smell

than others, and humans can be trained to detect and distinguish odors
that could not be detected without such training. See E. Hancock, A
Primer on Smell, http://www.jhu.edu/jhumag/996web/smell.html. Some
individuals employed in the perfume and wine industries, for example,
have an amazingly acute sense of smell. Ibid.
                 Cite as: 569 U. S. ____ (2013)           11

                     ALITO, J., dissenting

the use of a drug-sniffing dog is the same as the use of a
thermal imaging device. See Caballes, 543 U. S., at 409–
410. The very argument now advanced by the concurrence
appears in Justice Souter’s Caballes dissent. See id., at
413, and n. 3. But the Court was not persuaded.
   Contrary to the interpretation propounded by the con-
currence, Kyllo is best understood as a decision about the
use of new technology. The Kyllo Court focused on the fact
that the thermal imaging device was a form of “sense-
enhancing technology” that was “not in general public
use,” and it expressed concern that citizens would be “at
the mercy of advancing technology” if its use was not
restricted. 533 U. S., at 34–35. A dog, however, is not a
new form of “technology or a “device.” And, as noted, the
use of dogs’ acute sense of smell in law enforcement dates
back many centuries.
   The concurrence suggests that a Kyllo-based decision
would be “much like” the actual decision of the Court, but
that is simply not so. The holding of the Court is based on
what the Court sees as a “ ‘physical intrusion of a constitu-
tionally protected area.’ ” Ante, at 3 (quoting United States
v. Knotts, 460 U. S. 276, 286 (1983) (Brennan, J., concur-
ring in judgment)). As a result, it does not apply when a
dog alerts while on a public sidewalk or street or in the
corridor of a building to which the dog and handler have
been lawfully admitted.
   The concurrence’s Kyllo-based approach would have a
much wider reach. When the police used the thermal
imaging device in Kyllo, they were on a public street, 533
U. S., at 29, and “committed no trespass.” Ante, at 3.
Therefore, if a dog’s nose is just like a thermal imaging
device for Fourth Amendment purposes, a search would
occur if a dog alerted while on a public sidewalk or in the
corridor of an apartment building. And the same would be
true if the dog was trained to sniff, not for marijuana, but
for more dangerous quarry, such as explosives or for a
12                 FLORIDA v. JARDINES

                    ALITO, J., dissenting

violent fugitive or kidnaped child. I see no ground for
hampering legitimate law enforcement in this way.
                            IV
  The conduct of the police officer in this case did not
constitute a trespass and did not violate respondent’s
reasonable expectations of privacy. I would hold that this
conduct was not a search, and I therefore respectfully
dissent.
