The Santa Clara, Cal., police received an anonymous telephone
tip that marijuana was growing in respondent's backyard, which was
enclosed by two fences and shielded from view at ground level.
Officers who were trained in marijuana identification secured a
private airplane, flew over respondent's house at an altitude of
1,000 feet, and readily identified marijuana plants growing in the
yard. A search warrant was later obtained on the basis of one of
the officer's naked-eye observations; a photograph of the
surrounding area taken from the airplane was attached as an
exhibit. The warrant was executed, and marijuana plants were
seized. After the California trial court denied respondent's motion
to suppress the evidence of the search, he pleaded guilty to a
charge of cultivation of marijuana. The California Court of Appeal
reversed on the ground that the warrantless aerial observation of
respondent's yard violated the Fourth Amendment.
The Fourth Amendment was not violated by the
naked-eye aerial observation of respondent's backyard. Pp.
476 U. S.
(a) The touchstone of Fourth Amendment analysis is whether a
person has a constitutionally protected reasonable expectation of
privacy, which involves the two inquiries of whether the individual
manifested a subjective expectation of privacy in the object of the
challenged search, and whether society is willing to recognize that
expectation as reasonable. Ratz v. United States,
389 U. S. 347
pursuing the second inquiry, the test of legitimacy is not whether
the individual chooses to conceal assertedly "private activity,"
but whether the government's intrusion infringes upon the personal
and societal values protected by the Fourth Amendment. Pp.
476 U. S.
(b) On the record here, respondent's expectation of privacy from
all observations of his backyard was unreasonable. That the
backyard and its crop were within the "curtilage" of respondent's
home did not itself bar all police observation. The mere fact that
an individual has taken measures to restrict some views of his
activities does not preclude an officer's observation from a public
vantage point where he has a right to be and which renders the
activities clearly visible. The police observations here took place
within public navigable airspace, in a physically nonintrusive
manner. The police were able to observe the plants
Page 476 U. S. 208
readily discernible to the naked eye as marijuana, and it was
irrelevant that the observation from the airplane was directed at
identifying the plants and that the officers were trained to
recognize marijuana. Any member of the public flying in this
airspace who cared to glance down could have seen everything that
the officers observed. The Fourth Amendment simply does not require
police traveling in the public airways at 1,000 feet to obtain a
warrant in order to observe what is visible to the naked eye. Pp.
476 U. S.
161 Cal. App.
, 208 Cal. Rptr. 93, reversed.
BURGER, C.J., delivered the opinion of the Court, in which
WHITE, REHNQUIST, STEVENS, and O'CONNOR, JJ., joined. POWELL, J.,
filed a dissenting opinion, in which BRENNAN, MARSHALL, and
BLACKMUN, JJ., joined, post,
p. 476 U. S.
Page 476 U. S. 209
CHIEF JUSTICE BURGER delivered the opinion of the Court.
We granted certiorari to determine whether the Fourth Amendment
is violated by aerial observation without a warrant from an
altitude of 1,000 feet of a fenced-in backyard within the curtilage
of a home.
On September 2, 1982, Santa Clara Police received an anonymous
telephone tip that marijuana was growing in respondent's backyard.
Police were unable to observe the contents of respondent's yard
from ground level because of a 6-foot outer fence and a 10-foot
inner fence completely enclosing the yard. Later that day, Officer
Shutz, who was assigned to investigate, secured a private plane and
flew over respondent's house at an altitude of 1,000 feet, within
navigable airspace; he was accompanied by Officer Rodriguez. Both
officers were trained in marijuana identification. From the
overflight, the officers readily identified marijuana plants 8 feet
to 10 feet in height growing in a 15- by 25-foot plot in
respondent's yard; they photographed the area with a standard 35mm
On September 8, 1982, Officer Shutz obtained a search warrant on
the basis of an affidavit describing the anonymous tip and their
observations; a photograph depicting respondent's house, the
backyard, and neighboring homes was attached to the affidavit as an
exhibit. The warrant was
Page 476 U. S. 210
executed the next day, and 73 plants were seized; it is not
disputed that these were marijuana.
After the trial court denied respondent's motion to suppress the
evidence of the search, respondent pleaded guilty to a charge of
cultivation of marijuana. The California Court of Appeal reversed,
however, on the ground that the warrantless aerial observation of
respondent's yard which led to the issuance of the warrant violated
the Fourth Amendment. 161 Cal. App.
, 208 Cal. Rptr. 93 (1984). That court held first that
respondent's backyard marijuana garden was within the "curtilage"
of his home, under Oliver v. United States, 466 U.
(1984). The court emphasized that the height and
existence of the two fences constituted "objective criteria from
which we may conclude he manifested a reasonable expectation of
privacy by any standard." 161 Cal. App. 3d at 1089, 208 Cal. Rptr.
Examining the particular method of surveillance undertaken, the
court then found it "significant" that the flyover
"was not the result of a routine patrol conducted for any other
legitimate law enforcement or public safety objective, but was
undertaken for the specific purpose of observing this particular
enclosure within [respondent's] curtilage."
It held this focused observation was "a direct
and unauthorized intrusion into the sanctity of the home" which
violated respondent's reasonable expectation of privacy.
at 1089-1090, 208 Cal. Rptr. at 98 (footnote omitted).
The California Supreme Court denied the State's petition for
We granted the State's petition for certiorari, 471 U.S. 1134
(1985). We reverse.
The State argues that respondent has "knowingly exposed" his
backyard to aerial observation, because all that was seen was
visible to the naked eye from any aircraft flying overhead. The
State analogizes its mode of observation to a knothole or opening
in a fence: if there is an opening, the police may look.
Page 476 U. S. 211
The California Court of Appeal, as we noted earlier, accepted
the analysis that, unlike the casual observation of a private
person flying overhead, this flight was focused specifically on a
small suburban yard, and was not the result of any routine patrol
overflight. Respondent contends he has done all that can reasonably
be expected to tell the world he wishes to maintain the privacy of
his garden within the curtilage without covering his yard. Such
covering, he argues, would defeat its purpose as an outside living
area; he asserts he has not "knowingly" exposed himself to aerial
The touchstone of Fourth Amendment analysis is whether a person
has a "constitutionally protected reasonable expectation of
privacy." Katz v. United States, 389 U.
, 389 U. S. 360
(1967) (Harlan, J., concurring). Katz
posits a two-part
inquiry: first, has the individual manifested a subjective
expectation of privacy in the object of the challenged search?
Second, is society willing to recognize that expectation as
reasonable? See Smith v. Maryland, 442 U.
, 442 U. S. 740
Clearly -- and understandably -- respondent has met the test of
manifesting his own subjective intent and desire to maintain
privacy as to his unlawful agricultural pursuits. However, we need
not address that issue, for the State has not challenged the
finding of the California Court of Appeal that respondent had such
an expectation. It can reasonably be assumed that the 10-foot fence
was placed to conceal the marijuana crop from at least street-level
views. So far as the normal sidewalk traffic was concerned, this
fence served that purpose, because respondent "took normal
precautions to maintain his privacy." Rawlings v.
Kentucky, 448 U. S. 98
448 U. S. 105
Yet a 10-foot fence might not shield these plants from the eyes
of a citizen or a policeman perched on the top of a truck or a
two-level bus. Whether respondent therefore manifested
Page 476 U. S. 212
a subjective expectation of privacy from all
observations of his backyard, or whether instead he manifested
merely a hope that no one would observe his unlawful gardening
pursuits, is not entirely clear in these circumstances. Respondent
appears to challenge the authority of government to observe his
activity from any vantage point or place if the viewing is
motivated by a law enforcement purpose, and not the result of a
casual, accidental observation.
We turn, therefore, to the second inquiry under Katz,
whether that expectation is reasonable. In pursuing this
inquiry, we must keep in mind that "[t]he test of legitimacy is not
whether the individual chooses to conceal assertedly private'
activity," but instead "whether the government's intrusion
infringes upon the personal and societal values protected by the
Fourth Amendment." Oliver, supra, at 466 U. S.
Respondent argues that, because his yard was in the curtilage of
his home, no governmental aerial observation is permissible under
the Fourth Amendment without a warrant. [Footnote 1
] The history and genesis of the curtilage
doctrine are instructive.
"At common law, the curtilage is the area to which extends the
intimate activity associated with the 'sanctity of a man's home and
the privacies of life.'"
at 466 U. S. 180
(quoting Boyd v. United States, 116 U.
, 116 U. S. 630
4 Blackstone, Commentaries *225. The
Page 476 U. S. 213
protection afforded the curtilage is essentially a protection of
families and personal privacy in an area intimately linked to the
home, both physically and psychologically, where privacy
expectations are most heightened. The claimed area here was
immediately adjacent to a suburban home, surrounded by high double
fences. This close nexus to the home would appear to encompass this
small area within the curtilage. Accepting, as the State does, that
this yard and its crop fall within the curtilage, the question
remains whether naked-eye observation of the curtilage by police
from an aircraft lawfully operating at an altitude of 1,000 feet
violates an expectation of privacy that is reasonable.
That the area is within the curtilage does not itself bar all
police observation. 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. Nor does
the mere fact that an individual has taken measures to restrict
some views of his activities preclude an officer's observations
from a public vantage point where he has a right to be and which
renders the activities clearly visible. E.g., United States v.
Knotts, 460 U. S. 276
460 U. S. 282
(1983). "What a person knowingly exposes to the public, even in his
own home or office, is not a subject of Fourth Amendment
protection." Katz, supra,
at 389 U. S.
The observations by Officers Shutz and Rodriguez in this case
took place within public navigable airspace, see
U.S.C.App. § 1304, in a physically nonintrusive manner; from this
point, they were able to observe plants readily discernible to the
naked eye as marijuana. That the observation from aircraft was
directed at identifying the plants and the officers were trained to
recognize marijuana is irrelevant. Such observation is precisely
what a judicial officer needs to provide a basis for a warrant. Any
member of the public flying in this airspace who glanced down could
Page 476 U. S. 214
everything that these officers observed. On this record, we
readily conclude that respondent's expectation that his garden was
protected from such observation is unreasonable, and is not an
expectation that society is prepared to honor. [Footnote 2
The dissent contends that the Court ignores Justice Harlan's
warning in his concurrence in Katz v. United States,
U.S. at 389 U. S.
-362, that the Fourth Amendment should not be limited
to proscribing only physical intrusions onto private property.
at 476 U. S.
-216. But Justice Harlan's observations about future
electronic developments and the potential for electronic
interference with private communications, see Katz, supra,
at 389 U. S. 362
were plainly not aimed at simple visual observations from a public
place. Indeed, since Katz,
the Court has required warrants
for electronic surveillance aimed at intercepting private
conversations. See United States v. United States District
Court, 407 U. S. 297
Justice Harlan made it crystal clear that he was resting on the
reality that one who enters a telephone booth is entitled to assume
that his conversation is not being intercepted. This does not
translate readily into a rule of constitutional dimensions that one
who grows illicit drugs in his backyard is "entitled to assume" his
unlawful conduct will not be observed
Page 476 U. S. 215
by a passing aircraft -- or by a power company repair mechanic
on a pole overlooking the yard. As Justice Harlan emphasized,
"a man's home is, for most purposes, a place where he expects
privacy, but objects, activities, or statements that he exposes to
the 'plain view' of outsiders are not 'protected,' because no
intention to keep them to himself has been exhibited. On the other
hand, conversations in the open would not be protected against
being overheard, for the expectation of privacy under the
circumstances would be unreasonable."
at 389 U. S.
One can reasonably doubt that, in 1967, Justice Harlan
considered an aircraft within the category of future "electronic"
developments that could stealthily intrude upon an individual's
privacy. In an age where private and commercial flight in the
public airways is routine, it is unreasonable for respondent to
expect that his marijuana plants were constitutionally protected
from being observed with the naked eye from an altitude of 1,000
feet. The Fourth Amendment simply does not require the police
traveling in the public airways at this altitude to obtain a
warrant in order to observe what is visible to the naked eye.
Because the parties framed the issue in the California courts
below and in this Court as concerning only the reasonableness of
aerial observation generally, see
Pet. for Cert. i,
without raising any distinct issue as to the photograph attached as
an exhibit to the affidavit in support of the search warrant, our
analysis is similarly circumscribed. It was the officer's
observation, not the photograph, that supported the warrant.
Officer Shutz testified that the photograph did not identify the
marijuana as such, because it failed to reveal a "true
representation" of the color of the plants: "you have to see it
with the naked eye." App. 36.
The California Court of Appeal recognized that police have the
right to use navigable airspace, but made a pointed distinction
between police aircraft focusing on a particular home and police
aircraft engaged in a "routine patrol." It concluded that the
officers' "focused" observations violated respondent's reasonable
expectations of privacy. In short, that court concluded that a
regular police patrol plane identifying respondent's marijuana
would lead to a different result. Whether this is a rational
distinction is hardly relevant, although we find difficulty
understanding exactly how respondent's expectations of privacy from
aerial observation might differ when two airplanes pass overhead at
identical altitudes, simply for different purposes. We are cited to
no authority for this novel analysis or the conclusion it begat.
The fact that a ground-level observation by police "focused" on a
particular place is not different from a "focused" aerial
observation under the Fourth Amendment.
In Dow Chemical Co. v. United States, post,
476 U. S. 227
decided today, we hold that the use of an aerial mapping camera to
photograph an industrial manufacturing complex from navigable
airspace similarly does not require a warrant under the Fourth
Amendment. The State acknowledges that
"[a]erial observation of curtilage may become invasive, either
due to physical intrusiveness or through modern technology which
discloses to the senses those intimate associations, objects or
activities otherwise imperceptible to police or fellow
Brief for Petitioner 14-15.
JUSTICE POWELL, with whom JUSTICE BRENNAN, JUSTICE MARSHALL, and
JUSTICE BLACKMUN join, dissenting.
Concurring in Katz v. United States, 389 U.
(1967), Justice Harlan warned that any decision
to construe the
Page 476 U. S. 216
Fourth Amendment as proscribing only physical intrusions by
police onto private property
"is, in the present day, bad physics as well as bad law, for
reasonable expectations of privacy may be defeated by electronic as
well as physical invasion."
at 389 U. S. 362
Because the Court today ignores that warning in an opinion that
departs significantly from the standard developed in Katz
for deciding when a Fourth Amendment violation has occurred, I
As the Court's opinion reflects, the facts of this case are not
complicated. Officer Shutz investigated an anonymous report that
marijuana was growing in the backyard of respondent's home. A tall
fence prevented Shutz from looking into the yard from the street.
The yard was directly behind the home, so that the home itself
furnished one border of the fence. Shutz proceeded, without
obtaining a warrant, to charter a plane and fly over the home at an
altitude of 1,000 feet. Observing marijuana plants growing in the
fenced-in yard, Shutz photographed respondent's home and yard, as
well as homes and yards of neighbors. The photograph clearly shows
that the enclosed yard also contained a small swimming pool and
patio. Shutz then filed an affidavit, to which he attached the
photograph, describing the anonymous tip and his aerial observation
of the marijuana. A warrant issued, [Footnote 2/1
] and a search of the yard confirmed Shutz'
aerial observations. Respondent was arrested for cultivating
marijuana, a felony under California law.
Respondent contends that the police intruded on his
constitutionally protected expectation of privacy when they
conducted aerial surveillance of his home and photographed his
backyard without first obtaining a warrant. The Court
Page 476 U. S. 217
rejects that contention, holding that respondent's expectation
of privacy in the curtilage of his home, although reasonable as to
intrusions on the ground, was unreasonable as to surveillance from
the navigable airspace. In my view, the Court's holding rests on
only one obvious fact, namely, that the airspace generally is open
to all persons for travel in airplanes. The Court does not explain
why this single fact deprives citizens of their privacy interest in
outdoor activities in an enclosed curtilage.
The Fourth Amendment protects "[t]he right of the people to be
secure in their persons, houses, papers, and effects, against
unreasonable searches and seizures." While the familiar history of
the Amendment need not be recounted here, [Footnote 2/2
] we should remember that it reflects a
choice that our society should be one in which citizens "dwell in
reasonable security and freedom from surveillance." Johnson v.
United States, 333 U. S. 10
333 U. S. 14
(1948). Since that choice was made by the Framers of the
Constitution, our cases construing the Fourth Amendment have relied
in part on the common law for instruction on "what sorts of
searches the Framers . . . regarded as reasonable." Steagald v.
United States, 451 U. S. 204
451 U. S. 217
(1981). But we have repeatedly refused to freeze "into
constitutional law those enforcement practices that existed at the
time of the Fourth Amendment's passage.'" Id. at
451 U. S. 217,
n. 10, quoting Payton v. New York, 445 U.
S. 573, 445 U. S. 591,
n. 33 (1980). See United States v. United States District
Court, 407 U. S. 297,
407 U. S. 313
(1972). Rather, we have construed the Amendment "`in light of
contemporary norms and conditions,'" Steagald v. United States,
supra, at 451 U. S. 217,
n. 10, quoting Payton v. New York, supra, at 445 U. S. 591,
n. 33, in order to prevent "any stealthy encroachments" on our
citizens' right to be free of arbitrary official
Page 476 U. S. 218
Boyd v. United States, 116 U.
, 116 U. S. 635
(1886). Since the landmark decision in Katz v. United
the Court has fulfilled its duty to protect Fourth
Amendment rights by asking if police surveillance has intruded on
an individual's reasonable expectation of privacy.
As the decision in Katz
held, and dissenting opinions
written by Justices of this Court prior to Katz
recognized, e.g., Goldman v. United States, 316 U.
, 316 U. S.
-141 (1942) (Murphy, J., dissenting); Olmstead v.
United States, 277 U. S. 438
277 U. S. 474
(1928) (Brandeis, J., dissenting), a standard that defines a Fourth
Amendment "search" by reference to whether police have physically
invaded a "constitutionally protected area" provides no real
protection against surveillance techniques made possible through
technology. Technological advances have enabled police to see
people's activities and associations, and to hear their
conversations, without being in physical proximity. Moreover, the
capability now exists for police to conduct intrusive surveillance
without any physical penetration of the walls of homes or other
structures that citizens may believe shelters their privacy.
] Looking to the
Fourth Amendment for protection against such "broad and unsuspected
governmental incursions" into the "cherished privacy of law-abiding
citizens," United States v. United States District Court,
Page 476 U. S. 219
407 U. S.
-313 (footnote omitted), the Court in Katz
abandoned its inquiry into whether police had committed a physical
announced a standard under which the
occurrence of a search turned not on the physical position of the
police conducting the surveillance, but on whether the surveillance
in question had invaded a constitutionally protected reasonable
expectation of privacy.
Our decisions following the teaching of Katz
that this inquiry "normally embraces two discrete questions."
Smith v. Maryland, 442 U. S. 735
442 U. S. 740
(1979). "The first is whether the individual, by his conduct, has
exhibited an actual (subjective) expectation of privacy.'"
Ibid., quoting Katz v. United States, 389 U.S. at
389 U. S. 361
(Harlan, J., concurring). The second is whether that subjective
expectation "is `one that society is prepared to recognize as
"reasonable."'" 442 U.S. at 442 U. S. 740,
quoting Katz v. United States, supra, at 389 U. S. 361
(Harlan, J., concurring). While the Court today purports to
reaffirm this analytical framework, its conclusory rejection of
respondent's expectation of privacy in the yard of his residence as
one that "is unreasonable," ante at 476 U. S. 213,
represents a turning away from the principles that have guided our
Fourth Amendment inquiry. The Court's rejection of respondent's
Fourth Amendment claim is curiously at odds with its purported
reaffirmation of the curtilage doctrine, both in this decision and
its companion case, Dow Chemical Co. v. United States,
post p. 476 U. S. 227, and
particularly with its conclusion in Dow that society is
prepared to recognize as reasonable expectations of privacy in the
curtilage, post at 476 U. S.
The second question under Katz
has been described as
asking whether an expectation of privacy is "legitimate in the
sense required by the Fourth Amendment." [Footnote 2/4
] Oliver v.
Page 476 U. S. 220
466 U. S. 170
466 U. S. 182
(1984). The answer turns on "whether the government's intrusion
infringes upon the personal and societal values protected by the
Fourth Amendment." Id.
at 466 U. S.
-183. While no single consideration has been regarded
"the Court has given weight to such factors as the intention of
the Framers of the Fourth Amendment, . . . the uses to which the
individual has put a location, . . . and our societal understanding
that certain areas deserve the most scrupulous protection from
government invasion. [Footnote
at 466 U. S. 178
Our decisions have made clear that this inquiry often must be
decided by "reference to a place,'" Katz v. United States,
supra, at 389 U. S. 361
(Harlan, J., concurring); see Payton v. New York, 445 U.S.
at 445 U. S. 589,
and that a home is a place in which a subjective expectation of
privacy virtually always will be legitimate, ibid.;
see, e.g., United States v. Karo, 468 U.
S. 705, 468 U. S.
713-715 (1984); Steagald v. United States, 451
U.S. at 451 U. S.
"At the very core [of the Fourth Amendment] stands the right of
a [person] to retreat into his own home and there be free from
unreasonable governmental intrusion."
Silverman v. United States, 365 U.
, 365 U. S. 511
This case involves surveillance of a home, for as we stated in
Oliver v. United States,
the curtilage "has been
considered part of the home itself for Fourth Amendment purposes."
466 U.S. at 466 U. S. 80
Dow Chemical Co. v. United States,
Page 476 U. S. 221
decided today, the Court reaffirms that the "curtilage doctrine
evolved to protect much the same kind of privacy as that covering
the interior of a structure." Post
at 476 U. S. 235
The Court in Dow
emphasizes, moreover, that society
accepts as reasonable citizens' expectations of privacy in the area
immediately surrounding their homes. Ibid.
In deciding whether an area is within the curtilage, courts
"have defined the curtilage, as did the common law, by reference
to the factors that determine whether an individual reasonably may
expect that an area immediately adjacent to the home will remain
private. See, e.g., United States v. Van Dyke,
992, 993-994 (CA4 1981); United States v. Williams,
F.2d 451, 453 (CA5 1978); Care v. United States,
22, 25 (CA10), cert. denied,
351 U.S. 932 (1956)."
Oliver v. United States, supra,
at 466 U. S. 180
The lower federal courts have agreed that the curtilage is "an area
of domestic use immediately surrounding a dwelling and usually, but
not always, fenced in with the dwelling." [Footnote 2/6
] United States v.
LaBerge, 267 F.
, 692 (Md.1967); see United States v. Van
643 F.2d 992, 993, n. 1 (CA4 1984). Those courts also
have held that whether an area is within the curtilage must be
decided by looking at all of the facts. Ibid.,
Care v. United States, supra,
at 25. Relevant facts
include the proximity between the area claimed to be curtilage and
the home, the nature of the uses to which the area is put, and the
steps taken by the resident to protect the area from observation by
people passing by. See Care v. United States, supra,
25; see also United States v. Van Dyke, supra,
Page 476 U. S. 222
The Court begins its analysis of the Fourth Amendment issue
posed here by deciding that respondent had an expectation of
privacy in his backyard. I agree with that conclusion because of
the close proximity of the yard to the house, the nature of some of
the activities respondent conducted there, [Footnote 2/7
] and because he had taken steps to shield
those activities from the view of passersby. The Court then
implicitly acknowledges that society is prepared to recognize his
expectation as reasonable with respect to ground-level
surveillance, holding that the yard was within the curtilage, an
area in which privacy interests have been afforded the "most
heightened" protection. Ante
at 476 U. S. 213
As the foregoing discussion of the curtilage doctrine demonstrates,
respondent's yard unquestionably was within the curtilage. Since
Officer Shutz could not see into this private family area from the
street, the Court certainly would agree that he would have
conducted an unreasonable search had he climbed over the fence, or
used a ladder to peer into the yard without first securing a
warrant. See United States v. Van Dyke, supra; see also United
States v. Williams,
581 F.2d 451 (CA5 1978).
The Court concludes, nevertheless, that Shutz could use an
airplane -- a product of modern technology -- to intrude visually
into respondent's yard. The Court argues that respondent had no
reasonable expectation of privacy from aerial observation. It notes
that Shutz was "within public navigable airspace," ante
476 U. S. 213
when he looked into and photographed
Page 476 U. S. 223
respondent's yard. It then relies on the fact that the
surveillance was not accompanied by a physical invasion of the
Reliance on the manner
surveillance is directly contrary to the standard of Katz,
which identifies a constitutionally protected privacy right by
focusing on the interests of the individual and of a free society.
we have consistently held that the presence or
absence of physical trespass by police is constitutionally
irrelevant to the question whether society is prepared to recognize
an asserted privacy interest as reasonable. E.g., United States
v. United States District Court,
407 U.S. at 407 U. S.
The Court's holding, therefore, must rest solely on the fact
that members of the public fly in planes and may look down at homes
as they fly over them. Ante
at 476 U. S.
-214. The Court does not explain why it finds this
fact to be significant. One may assume that the Court believes that
citizens bear the risk that air travelers will observe activities
occurring within backyards that are open to the sun and air. This
risk, the Court appears to hold, nullifies expectations of privacy
in those yards even as to purposeful police surveillance from the
air. The Court finds support for this conclusion in United
States v. Knotts, 460 U. S. 276
at 476 U. S.
This line of reasoning is flawed. First, the actual risk to
privacy from commercial or pleasure aircraft is virtually
nonexistent. Travelers on commercial flights, as well as private
planes used for business or personal reasons, normally obtain at
most a fleeting, anonymous, and nondiscriminating glimpse of the
landscape and buildings over which they pass. [Footnote 2/8
] The risk that a passenger on such a
plane might observe
Page 476 U. S. 224
private activities, and might connect those activities with
particular people, is simply too trivial to protect against. It is
no accident that, as a matter of common experience, many people
build fences around their residential areas, but few build roofs
over their backyards. Therefore, contrary to the Court's
at 476 U. S. 213
people do not "knowingly expos[e]'" their residential yards
"`to the public'" merely by failing to build barriers that prevent
The Court's reliance on Knotts
reveals the second
problem with its analysis. The activities under surveillance in
took place on public streets, not in private homes.
460 U.S. at 460 U. S.
-282. Comings and goings on public streets are public
matters, and the Constitution does not disable police from
observing what every member of the public can see. The activity in
this case, by contrast, took place within the private area
immediately adjacent to a home. Yet the Court approves purposeful
police surveillance of that activity and area similar to that
approved in Knotts
with respect to public activities and
areas. The only possible basis for this holding is a judgment that
the risk to privacy posed by the remote possibility that a private
airplane passenger will notice outdoor activities is equivalent to
the risk of official aerial surveillance. [Footnote 2/9
] But the Court fails to acknowledge the
qualitative difference between police surveillance and other uses
made of the airspace. Members of the public use the airspace for
travel, business, or pleasure, not for the purpose of observing
activities taking place within residential yards. Here, police
conducted an overflight at low altitude solely for
Page 476 U. S. 225
the purpose of discovering evidence of crime within a private
enclave into which they were constitutionally forbidden to intrude
at ground level without a warrant. It is not easy to believe that
our society is prepared to force individuals to bear the risk of
this type of warrantless police intrusion into their residential
areas. [Footnote 2/10
Since respondent had a reasonable expectation of privacy in his
yard, aerial surveillance undertaken by the police for the purpose
of discovering evidence of crime constituted a "search" within the
meaning of the Fourth Amendment. "Warrantless searches are
presumptively unreasonable, though the Court has recognized a few
limited exceptions to this general rule." United States v.
468 U.S. at 468 U. S. 717
This case presents no such exception. The indiscriminate nature of
aerial surveillance, illustrated by Officer Shutz' photograph of
respondent's home and enclosed yard as well as those of his
neighbors, poses "far too serious a threat to privacy interests in
the home to escape entirely some sort of Fourth Amendment
at 468 U. S. 716
(footnote omitted). Therefore, I would affirm the judgment of the
California Court of Appeal ordering suppression of the marijuana
Some may believe that this case, involving no physical intrusion
on private property, presents "the obnoxious thing in its mildest
and least repulsive form." Boyd v. United
Page 476 U. S.
116 U.S. at 116 U. S. 635
But this Court recognized long ago that the essence of a Fourth
Amendment violation is "not the breaking of [a person's] doors, and
the rummaging of his drawers," but rather is "the invasion of his
indefeasible right of personal security, personal liberty and
private property." Id.
at 116 U. S. 630
Rapidly advancing technology now permits police to conduct
surveillance in the home itself, an area where privacy interests
are most cherished in our society, without any physical trespass.
While the rule in Katz
was designed to prevent silent and
unseen invasions of Fourth Amendment privacy rights in a variety of
settings, we have consistently afforded heightened protection to a
person's right to be left alone in the privacy of his house. The
Court fails to enforce that right or to give any weight to the
longstanding presumption that warrantless intrusions into the home
are unreasonable. [Footnote 2/11
The warrant authorized Shutz to search the home and its attached
garage, as well as the yard, for marijuana, narcotics
paraphernalia, records relating to marijuana sales, and documents
identifying the occupant of the premises.
See, e.g., Payton v. New York, 445 U.
, 445 U. S.
-585, n. 20 (1980).
As was said more than four decades ago:
"[T]he search of one's home or office no longer requires
physical entry, for science has brought forth far more effective
devices for the invasion of a person's privacy than the direct and
obvious methods of oppression which were detested by our forbears,
and which inspired the Fourth Amendment. . . . Whether the search
of private quarters is accomplished by placing on the outer walls
of the sanctum a detectaphone that transmits to the outside
listener the intimate details of a private conversation, or by new
methods of photography that penetrate walls or overcome distances,
the privacy of the citizen is equally invaded by the Government,
and intimate personal matters are laid bare to view."
Goldman v. United States, 316 U.
, 316 U. S. 139
(1942) (Murphy, J., dissenting). Since 1942, science has developed
even more sophisticated means of surveillance.
In Justice Harlan's classic description, an actual expectation
of privacy is entitled to Fourth Amendment protection if it is an
expectation that society recognizes as "reasonable." Katz v.
3899 U.S. at 389 U. S. 361
(Harlan, J., concurring). Since Katz,
our decisions also
have described constitutionally protected privacy interests as
those that society regards as "legitimate," using the words
"reasonable" and "legitimate" interchangeably. E.g., Oliver v.
United States, 466 U. S. 170
(1984); Rakas v. Illinois, 439 U.
, 439 U. S.
-144, n. 12 (1978).
"Legitimation of expectations of privacy by law must have a
source outside of the Fourth Amendment, either by reference to
concepts of real or personal property law or to understandings that
are recognized and permitted by society."
This inquiry necessarily focuses on personal
interests in privacy and liberty recognized by a free society.
The Oxford English Dictionary defines curtilage as
"a small court, yard, garth, or piece of ground attached to a
dwelling-house, and forming one enclosure with it, or so regarded
by the law; the area attached to and containing a dwelling-house
and its out-buildings."
2 Oxford English Dictionary 1278 (1933).
The Court omits any reference to the fact that respondent's yard
contained a swimming pool and a patio for sunbathing and other
private activities. At the suppression hearing, respondent sought
to introduce evidence showing that he did use his yard for domestic
activities. The trial court refused to consider that evidence. Tr.
on Appeal 5-8 (Aug. 16, 1983).
Of Course, during takeoff and landing, planes briefly fly at low
enough altitudes to afford fleeting opportunities to observe some
types of activity in the curtilages of residents who live within
the strictly regulated takeoff and landing zones. As all of us know
from personal experience, at least in passenger aircrafts, there
rarely -- if ever -- is an opportunity for a practical observation
and photographing of unlawful activity similar to that obtained by
Officer Shutz in this case. The Court's analogy to commercial and
private overflights, therefore, is wholly without merit.
Some of our precedents have held that an expectation of privacy
was not reasonable in part because the individual had assumed the
risk that certain kinds of private information would be turned over
to the police. United States v. Miller, 425 U.
, 425 U. S. 443
(1976). None of the prior decisions of this Court is a precedent
for today's decision. As JUSTICE MARSHALL has observed, it is our
duty to be sensitive to the risks that a citizen "should be forced
to assume in a free and open society." Smith v. Maryland,
442 U. S. 735
442 U. S. 750
(1979) (dissenting opinion).
The Court's decision has serious implications for outdoor family
activities conducted in the curtilage of a home. The feature of
such activities that makes them desirable to citizens living in a
free society, namely, the fact that they occur in the open air and
sunlight, is relied on by the Court as a justification for
permitting police to conduct warrantless surveillance at will.
Aerial surveillance is nearly as intrusive on family privacy as
physical trespass into the curtilage. It would appear that, after
today, families can expect to be free of official surveillance only
when they retreat behind the walls of their homes.
Of course, the right of privacy in the home and its curtilage
includes no right to engage in unlawful conduct there. But the
Fourth Amendment requires police to secure a warrant before they
may intrude on that privacy to search for evidence of suspected
crime. United States v. Karo, 468 U.
, 468 U. S.