(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 obtained 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 Amendment 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 intruding” on persons, houses, papers, or effects, “a ‘search’ within the

original meaning of the Fourth Amendment” has “undoubtedly occurred.” 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 unreasonable 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. Officers 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 specific 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 concurring 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, 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. 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 marijuana 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 searching. 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, Detective 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 Supreme 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 information 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 establishes 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 “undoubtedly 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 protections “when the Government does engage in [a] physical 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 belonging 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 permitted 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 intrusion.” 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 garden 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 Amendment 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 constitutionally protected area, we turn to the question of whether

it was accomplished through an unlicensed physical intrusion.1 While law enforcement officers need not “shield 

their eyes” when passing by the home “on public thoroughfares,” 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 Amendment’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 “undoubtedly familiar” to “every American statesman” at the time 

of the Founding, Boyd v. United States, 116 U. S. 616, 626 

—————— 

1At 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 officers 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 country,” notwithstanding the “strict rule of the English common 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. 

—————— 

2With 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, respectful, 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 invitation 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 detector, 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 

—————— 

3The dissent insists that our argument must rest upon “the particular instrument that Detective Bartelt used to detect the odor of marijuana”—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 dissent 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 concedes. See Tr. of Oral Arg. 6. 4The 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 approach 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 subjective 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 conduct a search, which is not what anyone would think he

had license to do. 

III 

The State argues that investigation by a forensic narcotics dog by definition cannot implicate any legitimate privacy 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 expectation 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 whereabouts 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 movements 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 reasonableexpectations 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 intruding on constitutionally protected areas. Jones, supra, at 

___ (slip op., at 8). 

Thus, we need not decide whether the officers’ investigation 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 physically 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 argument (echoed by the dissent) that forensic dogs have 

been commonly used by police for centuries. This argument 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 without physical intrusion.” Id., at 40 (emphasis added). But 

the implication of that statement (inclusio unius est exclusio 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 investigate 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-highpowered 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 uncommon 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 members 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 supersensitive instrument, which they deployed to detect things

inside that they could not perceive unassisted. The equipment 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 binoculars 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 today. Was it also an invasion of privacy? Yes, that as well. 

The Court today treats this case under a property rubric; 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 “practical 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 California 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 proceeding 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 resolved it.1 The Kyllo Court held that police officers conducted 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 following 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 

—————— 

1The 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 automobile during a traffic stop. See also Florida v. Harris, 568 U. S. ___ 

(2013). And we have held, over and over again, that people’s expectations 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 drugdetection dog) to “explore details of the home” (the presence 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 expectation “that exists, and that is acknowledged to be reasonable.” 533 U. S., at 34, 36.2 That does not mean the device 

—————— 

2The 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 detectible 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 irrelevant. The fact that equivalent information could sometimes be obtained 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 10, 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, JUSTICE KENNEDY, and JUSTICE BREYER join, dissenting. 

The Court’s decision in this important Fourth Amendment 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 incriminating 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 centuries.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 

—————— 

1See, e.g., Sloane, Dogs in War, Police Work and on Patrol, 46 J.

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

Life in 18th-Century England 32–33 (1999). 3Sloane 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 airborne 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 immediately returned to their patrol car. Id., at 98. 

A critical fact that the Court omits is that, as respondent’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 approximately 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 

—————— 

4See App. 94; App. to Brief for Respondent 1A (depiction of respondent’s home). 5The 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 proceed 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 encompasses 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 between police officers on agreeable and disagreeable missions (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 intentions 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, driveways, 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 invitation. 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 ordinary 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 example, mail carriers, persons making deliveries, and individuals 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 private 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 evidence that will lead to the homeowner’s arrest and prosecution, 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 Amendment 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 likewise constitute searches. With the exception of visits to 
 

8 FLORIDA v. JARDINES 

ALITO, J., dissenting 

serve warrants or civil process, police almost always approach 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 “objective 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 evidence by means other than talking. The officer may observe 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 Responsibilities 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 Parliaments 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 alternative ground for today’s decision, namely, that Detective 

Bartelt’s conduct violated respondent’s reasonable expectations 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 reasonable 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 fermenting 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 occupant reason as follows? “I know that odors may emanate 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 

—————— 

6Some 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 concurrence, 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 “senseenhancing 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 constitutionally protected area.’” Ante, at 3 (quoting United States 

v. Knotts, 460 U. S. 276, 286 (1983) (Brennan, J., concurring 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.