U.S. Supreme Court Oliver v. United States, 466
U.S. 170 (1984) Oliver v. United
States No. 82-15 Argued November 9,
1983 Decided April 17, 1984 466
U.S. 170 ast|>* 466
U.S. 170 CERTIORARI TO THE UNITED STATES
COURT OF APPEALS FOR THE SIXTH CIRCUIT Syllabus In No. 82-15, acting on reports that marihuana was being raised
on petitioner's farm, narcotics agents of the Kentucky State Police
went to the farm to investigate. Arriving at the farm, they drove
past petitioner's house to a locked gate with a "No Trespassing"
sign, but with a footpath around one side. The agents then walked
around the gate and along the road and found a field of marihuana
over a mile from petitioner's house. Petitioner was arrested and
indicted for "manufactur[ing]" a "controlled substance" in
violation of a federal statute. After a pretrial hearing, the
District Court suppressed evidence of the discovery of the
marihuana field, applying Katz v. United States, 389 U. S. 347 , and
holding that petitioner had a reasonable expectation that the field
would remain private and that it was not an "open" field that
invited casual intrusion. The Court of Appeals reversed, holding
that Katz had not impaired the vitality of the open fields
doctrine of Hester v. United States, 265 U. S.
57 , which permits police officers to enter and search a
field without a warrant. In No. 82-1273, after receiving a tip that
marihuana was being grown in the woods behind respondent's
residence, police officers entered the woods by a path between the
residence and a neighboring house, and followed a path through the
woods until they reached two marihuana patches fenced with chicken
wire and having "No Trespassing" signs. Later, the officers, upon
determining that the patches were on respondent's property,
obtained a search warrant and seized the marihuana. Respondent was
then arrested and indicted. The Maine trial court granted
respondent's motion to suppress the fruits of the second search,
holding that the initial warrantless search was unreasonable, that
the "No Trespassing" signs and secluded location of the marihuana
patches evinced a reasonable expectation of privacy, and that
therefore the open fields doctrine did not apply. The Maine Supreme
Judicial Court affirmed. Held: The open fields doctrine should be applied in
both cases to determine whether the discovery or seizure of the
marihuana in question was valid. Pp. 466 U. S.
176 -184. Page 466 U. S. 171 (a) That doctrine was founded upon the explicit language of the
Fourth Amendment, whose special protection accorded to "persons
houses, papers, and effects" does "not exten[d] to the open
fields." Hester v. United States, supra, at 265 U. S. 59 . Open
fields are not "effects" within the meaning of the Amendment, the
term "effects" being less inclusive than "property," and not
encompassing open fields. The government's intrusion upon open
fields is not one of those "unreasonable searches" proscribed by
the Amendment. Pp. 466 U. S.
176 -177.

															(b) Since Katz v. United States, supra, the touchstone
of Fourth Amendment analysis has been whether a person has a
"constitutionally protected reasonable expectation of privacy." Id. at 389 U. S. 360 .
The Amendment does not protect the merely subjective expectation of
privacy, but only those "expectation[s] that society is prepared to
recognize as reasonable.'" Id. at 389 U. S. 361 .
Because open fields are accessible to the public and the police in
ways that a home, office, or commercial structure would not be, and
because fences or "No Trespassing" signs do not effectively bar the
public from viewing open fields, the asserted expectation of
privacy in open fields is not one that society recognizes as
reasonable. Moreover, the common law, by implying that only the
land immediately surrounding and associated with the home warrants
the Fourth Amendment protections that attach to the home,
conversely implies that no expectation of privacy legitimately
attaches to open fields. Pp. 466 U. S.
177 -181. (c) Analysis of the circumstances of the search of an open field
on a case-by-case basis to determine whether reasonable
expectations of privacy were violated would not provide a workable
accommodation between the needs of law enforcement and the
interests protected by the Fourth Amendment. Such an ad
hoc approach not only would make it difficult for the
policeman to discern the scope of his authority, but also would
create the danger that constitutional rights would be arbitrarily
and inequitably enforced. Pp. 466 U. S.
181 -182.

															(d) Steps taken to protect privacy, such as planting the
marihuana on secluded land and erecting fences and "No Trespassing"
signs around the property, do not establish that expectations of
privacy in an open field are legitimate in the sense required by
the Fourth Amendment. 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 Amendment. The fact that the
government's intrusion upon an open field is a trespass at common
law does not make it a "search" in the constitutional sense. In the
case of open fields, the general rights of property protected by
the common law of trespass have little or no relevance to the
applicability of the Fourth Amendment. Pp. 466 U. S.
182 -184.

															686 F.2d 356, affirmed; 453 A.2d
489 , reversed and remanded. Page 466 U. S. 172 POWELL, J., delivered the opinion of the Court, in which BURGER,
C.J., and BLACKMUN, REHNQUIST, and O'CONNOR, JJ., joined, and in
Parts I and II of which WHITE, J., joined. WHITE, J., filed an
opinion concurring in part and concurring in the judgment, post, p. 466 U. S. 184 .
MARSHALL, J., filed a dissenting opinion, in which BRENNAN and
STEVENS, JJ., joined, post p. 466 U. S.
184 . Page 466 U. S. 173 JUSTICE POWELL delivered the opinion of the Court.

															The "open fields" doctrine, first enunciated by this Court in Hester v. United States, 265 U. S. 57 (1924), permits police officers to enter and search a field without
a warrant. We granted certiorari in these cases to clarify
confusion that has arisen as to the continued vitality of the
doctrine. I No. 8215. Acting on reports that marihuana was being
raised on the farm of petitioner Oliver, two narcotics agents of
the Kentucky State Police went to the farm to investigate.
[ Footnote 1 ] Arriving at the
farm, they drove past petitioner's house to a locked gate with a
"No Trespassing" sign. A footpath led around one side of the gate.
The agents walked around the gate and along the road for several
hundred yards, passing a barn and a parked camper. At that point,
someone standing in front of the camper shouted: "No hunting is
allowed, come back up here." The officers shouted back that they
were Kentucky State Police officers, but found no one when they
returned to the camper. The officers resumed their investigation of
the farm and found a field of marihuana over a mile from
petitioner's home.

															Petitioner was arrested and indicted for "manufactur[ing]" a
"controlled substance." 21 U.S.C. § 841(a)(1). After a pretrial
hearing, the District Court suppressed evidence of the discovery of
the marihuana field. Applying Katz v. United States, 389 U. S. 347 , 389 U. S. 357 (1967), the court found that petitioner had a reasonable
expectation that the field would remain private because petitioner
"had done all that could be expected of him to assert his privacy
in the area of farm that was searched." He had posted "No
Trespassing" signs at regular intervals and had locked the gate at
the entrance to the center of the farm. App. to Pet. for Cert. in
No. 82-15, Page 466 U. S. 174 pp. 23-24. Further, the court noted that the field itself is
highly secluded: it is bounded on all sides by woods, fences, and
embankments, and cannot be seen from any point of public access.
The court concluded that this was not an "open" field that invited
casual intrusion.

															The Court of Appeals for the Sixth Circuit, sitting en banc,
reversed the District Court. 686 F.2d 356 (1982). [ Footnote 2 ] The court concluded that Katz, upon which the District Court relied, had not
impaired the vitality of the open fields doctrine of Hester. Rather, the open fields doctrine was entirely
compatible with Katz' emphasis on privacy. The court
reasoned that the "human relations that create the need for privacy
do not ordinarily take place" in open fields, and that the property
owner's common law right to exclude trespassers is insufficiently
linked to privacy to warrant the Fourth Amendment's protection. 686
F.2d at 360. [ Footnote 3 ] We
granted certiorari. 459 U.S. 1168 (1983). No. 82-1273. After receiving an anonymous tip that
marihuana was being grown in the woods behind respondent Thornton's
residence, two police officers entered the woods by a path between
this residence and a neighboring house. They followed a footpath
through the woods until they reached two marihuana patches fenced
with chicken wire. Later, the officers determined that the patches
were on the property of respondent, obtained a warrant to search
the property, and seized the marihuana. On the basis of this
evidence, respondent was arrested and indicted. Page 466 U. S. 175 The trial court granted respondent's motion to suppress the
fruits of the second search. The warrant for this search was
premised on information that the police had obtained during their
previous warrantless search, that the court found to be
unreasonable. [ Footnote 4 ] "No
Trespassing" signs and the secluded location of the marihuana
patches evinced a reasonable expectation of privacy. Therefore, the
court held, the open fields doctrine did not apply.

															The Maine Supreme Judicial Court affirmed. 453 A.2d
489 (1982). It agreed with the trial court that the correct
question was whether the search "is a violation of privacy on which
the individual justifiably relied," id. at 493, and that
the search violated respondent's privacy. The court also agreed
that the open fields doctrine did not justify the search. That
doctrine applies, according to the court, only when officers are
lawfully present on property and observe "open and patent"
activity. Id. at 495. In this case, the officers had
trespassed upon defendant's property, and the respondent had made
every effort to conceal his activity. We granted certiorari. 460
U.S. 1068 (1983). [ Footnote
5 ] Page 466 U. S. 176 II The rule announced in Hester v. United States was
founded upon the explicit language of the Fourth Amendment. That
Amendment indicates with some precision the places and things
encompassed by its protections. As Justice Holmes explained for the
Court in his characteristically laconic style:

															"[T]he special protection accorded by the Fourth Amendment to
the people in their 'persons, houses, papers, and effects' is not
extended to the open fields. The distinction between the latter and
the house is as old as the common law." Hester v. United States, 265 U.S. at 265 U. S. 59 .
[ Footnote 6 ]

															Nor are the open fields "effects" within the meaning of the
Fourth Amendment. In this respect, it is suggestive that James
Madison's proposed draft of what became the Fourth Page 466 U. S. 177 Amendment preserves

															"[t]he rights of the people to be secured in their persons,
their houses, their papers, and their other property, from all
unreasonable searches and seizures. . . ." See N. Lasson, The History and Development of the
Fourth Amendment to the United States Constitution 100, n. 77
(1937). Although Congress' revisions of Madison's proposal
broadened the scope of the Amendment in some respects, id. at 100-103, the term "effects" is less inclusive than "property,"
and cannot be said to encompass open fields. [ Footnote 7 ] We conclude, as did the Court in
deciding Hester v. United States, that the government's
intrusion upon the open fields is not one of those "unreasonable
searches" proscribed by the text of the Fourth Amendment. III This interpretation of the Fourth Amendment's language is
consistent with the understanding of the right to privacy expressed
in our Fourth Amendment jurisprudence. Since Katz v. United
States, 389 U. S. 347 (1967), the touchstone of Amendment analysis has been the question
whether a person has a "constitutionally protected reasonable
expectation of privacy." Id. at 389 U. S. 360 (Harlan, J., concurring). The Amendment does not protect the merely
subjective expectation of privacy, but only those "expectation[s]
that society is prepared to recognize as reasonable.'" Id. at 389 U. S. 361 . See also Smith v. Maryland, 442 U.
S. 735 , 442 U. S.
740 -741 (1979). A No single factor determines whether an individual legitimately
may claim under the Fourth Amendment that a place should be free of
government intrusion not authorized by warrant. See Rakas v.
Illinois, 439 U. S. 128 , 439 U. S.
152 -153 Page 466 U. S. 178 (1978) (POWELL, J., concurring). In assessing the degree to
which a search infringes upon individual privacy, the Court has
given weight to such factors as the intention of the Framers of the
Fourth Amendment, e.g., United States v. Chadwick, 433 U. S. 1 , 433 U. S. 7 -8
(1977), the uses to which the individual has put a location, e.g., Jones v. United States, 362 U.
S. 257 , 362 U. S. 265 (1960), and our societal understanding that certain areas deserve
the most scrupulous protection from government invasion, e.g.,
Payton v. New York, 445 U. S. 573 (1980). These factors are equally relevant to determining whether
the government's intrusion upon open fields without a warrant or
probable cause violates reasonable expectations of privacy, and is
therefore a search proscribed by the Amendment.

															In this light, the rule of Hester v. United States,
supra, that we reaffirm today, may be understood as providing
that an individual may not legitimately demand privacy for
activities conducted out of doors in fields, except in the area
immediately surrounding the home. See also Air Pollution
Variance Bd. v. Western Alfalfa Corp., 416 U.
S. 861 , 416 U. S. 865 (1974). This rule is true to the conception of the right to privacy
embodied in the Fourth Amendment. The Amendment reflects the
recognition of the Framers that certain enclaves should be free
from arbitrary government interference. For example, the Court,
since the enactment of the Fourth Amendment, has stressed "the
overriding respect for the sanctity of the home that has been
embedded in our traditions since the origins of the Republic." Payton v. New York, supra, at 445 U. S. 601 .
[ Footnote 8 ] See also Silverman v. United States, 365 U.
S. 505 , 365 U. S. 511 (1961); United States v. United States District Court, 407 U. S. 297 , 407 U. S. 313 (1972). Page 466 U. S. 179 In contrast, open fields do not provide the setting for those
intimate activities that the Amendment is intended to shelter from
government interference or surveillance. There is no societal
interest in protecting the privacy of those activities, such as the
cultivation of crops, that occur in open fields. Moreover, as a
practical matter, these lands usually are accessible to the public
and the police in ways that a home, an office, or commercial
structure would not be. It is not generally true that fences or "No
Trespassing" signs effectively bar the public from viewing open
fields in rural areas. And both petitioner Oliver and respondent
Thornton concede that the public and police lawfully may survey
lands from the air. [ Footnote
9 ] For these reasons, the asserted expectation of privacy in
open fields is not an expectation that "society recognizes as
reasonable." [ Footnote
10 ] Page 466 U. S. 180 The historical underpinnings of the open fields doctrine also
demonstrate that the doctrine is consistent with respect for
"reasonable expectations of privacy." As Justice Holmes, writing
for the Court, observed in Hester, 265 U.S. at 265 U. S. 59 , the
common law distinguished "open fields" from the "curtilage," the
land immediately surrounding and associated with the home. See 4 W. Blackstone, Commentaries *225. The distinction
implies that only the curtilage, not the neighboring open fields,
warrants the Fourth Amendment protections that attach to the home.
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," Boyd v. United States, 116 U. S. 616 , 116 U. S. 630 (1886), and therefore has been considered part of the home itself
for Fourth Amendment purposes. Thus, courts have extended Fourth
Amendment protection to the curtilage; and they 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, 643 F.2d 992, 993-994 (CA4
1981); United States v. Williams, 581 F.2d 451, 453 (CA5
1978); Care v. United States, 231 F.2d 22, 25 (CA10), cert. denied, 351 U.S. 932 (1956). Conversely, the common
law implies, as we reaffirm today, that no expectation of privacy
legitimately attaches to open fields. [ Footnote 11 ] Page 466 U. S. 181 We conclude, from the text of the Fourth Amendment and from the
historical and contemporary understanding of its purposes, that an
individual has no legitimate expectation that open fields will
remain free from warrantless intrusion by government officers. B Petitioner Oliver and respondent Thornton contend, to the
contrary, that the circumstances of a search sometimes may indicate
that reasonable expectations of privacy were violated, and that
courts therefore should analyze these circumstances on a
case-by-case basis. The language of the Fourth Amendment itself
answers their contention.

															Nor would a case-by-case approach provide a workable
accommodation between the needs of law enforcement and the
interests protected by the Fourth Amendment. Under this approach,
police officers would have to guess before every search whether
landowners had erected fences sufficiently high, posted a
sufficient number of warning signs, or located contraband in an
area sufficiently secluded to establish a right of privacy. The
lawfulness of a search would turn on

															"'[a] highly sophisticated set of rules, qualified by all sorts
of ifs, ands, and buts, and requiring the drawing of subtle nuances
and hairline distinctions. . . .'" New York v. Belton, 453 U. S. 454 , 453 U. S. 458 (1981) (quoting LaFave, "Case-By-Case Adjudication" versus
"Standardized Procedures": The Robinson Dilemma, 1974 S.Ct.Rev.
127, 142). This Court repeatedly has acknowledged the difficulties
created for courts, police, and citizens by an ad hoc, case-by-case
definition of Fourth Amendment standards to be applied in differing
factual circumstances. See Belton, supra, at 453 U. S.
458 -460; Robbins v. California, 453 U.
S. 420 , 453 U. S. 430 (1981) (POWELL, J., concurring in judgment); Dunaway v. New
York, 442 U. S. 200 , 442 U. S.
213 -214 (1979); United States v. Robinson, 414 U. S. 218 , 414 U. S. 235 (1973). The ad hoc approach not only makes it difficult
for the policeman to discern the scope of his authority, Belton, supra, at 453 U. S. 460 ; it also creates a danger that
constitutional Page 466 U. S. 182 rights will be arbitrarily and inequitably enforced. Cf.
Smith v. Goguen, 415 U. S. 566 , 415 U. S.
572 -573 (1974). [ Footnote 12 ] IV In any event, while the factors that petitioner Oliver and
respondent Thornton urge the courts to consider may be relevant to
Fourth Amendment analysis in some contexts, these factors cannot be
decisive on the question whether the search of an open field is
subject to the Amendment. Initially, we reject the suggestion that
steps taken to protect privacy establish that expectations of
privacy in an open field are legitimate. It is true, of course,
that petitioner Oliver and respondent Thornton, in order to conceal
their criminal activities, planted the marihuana upon secluded land
and erected fences and "No Trespassing" signs around the property.
And it may be that, because of such precautions, few members of the
public stumbled upon the marihuana crops seized by the police.
Neither of these suppositions demonstrates, however, that the
expectation of privacy was legitimate in the sense required by the
Fourth Amendment. The test of legitimacy is not whether the
individual chooses to conceal assertedly "private" activity.
[ Footnote 13 ] Rather, the
correct inquiry is whether the government's intrusion infringes
upon the personal Page 466 U. S. 183 and societal values protected by the Fourth Amendment. As we
have explained, we find no basis for concluding that a police
inspection of open fields accomplishes such an infringement.

															Nor is the government's intrusion upon an open field a "search"
in the constitutional sense because that intrusion is a trespass at
common law. The existence of a property right is but one element in
determining whether expectations of privacy are legitimate.
" The premise that property interests control the right of the
Government to search and seize has been discredited.'" Katz, 389 U.S. at 389 U. S. 353 (quoting Warden v. Hayden, 387 U. S. 294 , 387 U. S. 304 (1967)). "[E]ven a property interest in premises may not be sufficient to
establish a legitimate expectation of privacy with respect to
particular items located on the premises or activity conducted
thereon." Rakas v. Illinois, 439 U.S. at 439 U. S. 144 ,
n. 12.

															The common law may guide consideration of what areas are
protected by the Fourth Amendment by defining areas whose invasion
by others is wrongful. Id. at 430 U. S. 153 (POWELL, J., concurring). [ Footnote 14 ] The law of trespass, however, forbids
intrusions upon land that the Fourth Amendment would not proscribe.
For trespass law extends to instances where the exercise of the
right to exclude vindicates no legitimate privacy interest.
[ Footnote 15 ] Thus, in the
case of open fields, the general Page 466 U. S. 184 rights of property protected by the common law of trespass have
little or no relevance to the applicability of the Fourth
Amendment. V We conclude that the open fields doctrine, as enunciated in Hester, is consistent with the plain language of the
Fourth Amendment and its historical purposes. Moreover, Justice
Holmes' interpretation of the Amendment in Hester accords
with the "reasonable expectation of privacy" analysis developed in
subsequent decisions of this Court. We therefore affirm Oliver
v. United States; Maine v. Thornton is reversed and remanded
for further proceedings not inconsistent with this opinion. It is so ordered. * Together with No. 82-1273, Maine v. Thornton, on
certiorari to the Supreme Judicial Court of Maine.

															[ Footnote 1 ]

															It is conceded that the police did not have a warrant
authorizing the search, that there was no probable cause for the
search, and that no exception to the warrant requirement is
applicable.

															[ Footnote 2 ]

															A panel of the Sixth Circuit had affirmed the suppression order.
657 F.2d 85 (1981).

															[ Footnote 3 ]

															The four dissenting judges contended that the open fields
doctrine did not apply where, as in this case, "reasonable
effort[s] [have] been made to exclude the public." 686 F.2d at 372.
To that extent, the dissent considered that Katz v. United
States implicitly had overruled previous holdings of this
Court. The dissent then concluded that petitioner had established a
"reasonable expectation of privacy" under the Katz standard. Judge Lively also wrote separately to argue that the open
fields doctrine applied only to lands that could be viewed by the
public.

															[ Footnote 4 ]

															The court also discredited other information, supplied by a
confidential informant, upon which the police had based their
warrant application.

															[ Footnote 5 ]

															Respondent contends that the decision below rests upon adequate
and independent state law grounds. We do not read that decision,
however, as excluding the evidence because the search violated the
State Constitution. The Maine Supreme Judicial Court referred only
to the Fourth Amendment of the Federal Constitution, and purported
to apply the Katz test; the prior state cases that the
court cited also construed the Federal Constitution. In any case,
the Maine Supreme Judicial Court did not articulate an independent
state ground with the clarity required by Michigan v.
Long, 463 U. S. 1032 (1983).

															Contrary to respondent's assertion, we do not review here the
state courts' finding as a matter of "fact" that the area searched
was not an "open field." Rather, the question before us is the
appropriate legal standard for determining whether search of that
area without a warrant was lawful under the Federal
Constitution.

															The conflict between the two cases that we review here is
illustrative of the confusion the open fields doctrine has
generated among the state and federal courts. Compare, e.g.,
State v. Byers, 359 So.
2d 84 (La.1978) (refusing to apply open fields doctrine); State v. Brady, 406 So. 2d
1093 (Fla.1981) (same), with United States v. Lace, 669 F.2d 46, 50-51 (CA2 1982); United States v. Freie, 545
F.2d 1217 (CA9 1976); United States v. Brown, 473 F.2d
952, 954 (CA5 1973); Atwell v. United States, 414 F.2d
136, 138 (CA5 1969).

															[ Footnote 6 ]

															The dissent offers no basis for its suggestion that Hester rests upon some narrow, unarticulated principle,
rather than upon the reasoning enunciated by the Court's opinion in
that case. Nor have subsequent cases discredited Hester's reasoning. This Court frequently has relied on the explicit
language of the Fourth Amendment as delineating the scope of its
affirmative protections. See, e.g., Robbins v. California, 453 U. S. 420 , 453 U. S. 426 (1981) (opinion of Stewart, J.); Payton v. New York, 445 U. S. 573 , 445 U. S.
589 -590 (1980); Alderman v. United States, 394 U. S. 165 , 394 U. S.
178 -180 (1969). As these cases, decided after Katz, indicate, Katz' "reasonable expectation of
privacy" standard did not sever Fourth Amendment doctrine from the
Amendment's language. Katz itself construed the
Amendment's protection of the person against unreasonable searches
to encompass electronic eavesdropping of telephone conversations
sought to be kept private; and Katz' fundamental
recognition that "the Fourth Amendment protects people -- and not
simply areas' -- against unreasonable searches and seizures," see 389 U.S. at 389 U. S. 353 ,
is faithful to the Amendment's language. As Katz demonstrates, the Court fairly may respect the constraints of the
Constitution's language without wedding itself to an unreasoning
literalism. In contrast, the dissent's approach would ignore the
language of the Constitution itself, as well as overturn this
Court's governing precedent. [ Footnote 7 ]

															The Framers would have understood the term "effects" to be
limited to personal, rather than real, property. See generally
Doe v. Dring, 2 M. & S. 448, 454, 105 Eng.Rep. 447, 449
(K. B. 1814) (discussing prior cases); 2 W. Blackstone,
Commentaries *16, *384-*385.

															[ Footnote 8 ]

															The Fourth Amendment's protection of offices and commercial
buildings, in which there may be legitimate expectations of
privacy, is also based upon societal expectations that have deep
roots in the history of the Amendment. See Marshall v.
Barlow's, Inc., 436 U. S. 307 , 436 U. S. 311 (1978); G. M. Leasing Corp. v. United States, 429 U.
S. 338 , 429 U. S. 355 (1977).

															[ Footnote 9 ]

															Tr. of Oral Arg. 14-15, 58. See, e.g., United States v.
Allen, 675 F.2d 1373, 1380-1381 (CA9 1980); United States
v. DeBacker, 493 F.
Supp. 1078 , 1081 (WD Mich.1980). In practical terms, petitioner
Oliver's and respondent Thornton's analysis merely would require
law enforcement officers, in most situations, to use aerial
surveillance to gather the information necessary to obtain a
warrant or to justify warrantless entry onto the property. It is
not easy to see how such a requirement would advance legitimate
privacy interests.

															[ Footnote 10 ]

															The dissent conceives of open fields as bustling with private
activity as diverse as lovers' trysts and worship services. Post at 466 U. S.
191 -193. But in most instances, police will disturb no
one when they enter upon open fields. These fields, by their very
character as open and unoccupied, are unlikely to provide the
setting for activities whose privacy is sought to be protected by
the Fourth Amendment. One need think only of the vast expanse of
some western ranches or of the undeveloped woods of the Northwest
to see the unreality of the dissent's conception. Further, the
Fourth Amendment provides ample protection to activities in the
open fields that might implicate an individual's privacy. An
individual who enters a place defined to be "public" for Fourth
Amendment analysis does not lose all claims to privacy or personal
security. Cf. Arkansas v. Sanders, 442 U.
S. 753 , 442 U. S.
766 -767 (1979) (BURGER, C.J., concurring in judgment).
For example, the Fourth Amendment's protections against
unreasonable arrest or unreasonable seizure of effects upon the
person remain fully applicable. See, e.g., United States v.
Watson, 423 U. S. 411 (1976).

															[ Footnote 11 ]

															Neither petitioner Oliver nor respondent Thornton has contended
that the property searched was within the curtilage. Nor is it
necessary in these cases to consider the scope of the curtilage
exception to the open fields doctrine or the degree of Fourth
Amendment protection afforded the curtilage, as opposed to the home
itself. It is clear, however, that the term "open fields" may
include any unoccupied or undeveloped area outside of the
curtilage. An open field need be neither "open" nor a "field" as
those terms are used in common speech. For example, contrary to
respondent Thornton's suggestion, Tr. of Oral Arg. 21-22, a thickly
wooded area nonetheless may be an open field as that term is used
in construing the Fourth Amendment. See, e.g., United States v.
Pruitt, 464 F.2d 494 (CA9 1972); Bedell v. State, 257
Ark. 895, 521 S.W.2d
200 (1975).

															[ Footnote 12 ]

															The clarity of the open fields doctrine that we reaffirm today
is not sacrificed, as the dissent suggests, by our recognition that
the curtilage remains within the protections of the Fourth
Amendment. Most of the many millions of acres that are "open
fields" are not close to any structure, and so not arguably within
the curtilage. And, for most homes, the boundaries of the curtilage
will be clearly marked; and the conception defining the curtilage
-- as the area around the home to which the activity of home life
extends -- is a familiar one easily understood from our daily
experience. The occasional difficulties that courts might have in
applying this, like other, legal concepts do not argue for the
unprecedented expansion of the Fourth Amendment advocated by the
dissent.

															[ Footnote 13 ]

															Certainly the Framers did not intend that the Fourth Amendment
should shelter criminal activity wherever persons with criminal
intent choose to erect barriers and post "No Trespassing"
signs.

															[ Footnote 14 ]

															As noted above, the common law conception of the "curtilage" has
served this function.

															[ Footnote 15 ]

															The law of trespass recognizes the interest in possession and
control of one's property, and for that reason permits exclusion of
unwanted intruders. But it does not follow that the right to
exclude conferred by trespass law embodies a privacy interest also
protected by the Fourth Amendment. To the contrary, the common law
of trespass furthers a range of interests that have nothing to do
with privacy, and that would not be served by applying the
strictures of trespass law to public officers. Criminal laws
against trespass are prophylactic: they protect against intruders
who poach, steal livestock and crops, or vandalize property. And
the civil action of trespass serves the important function of
authorizing an owner to defeat claims of prescription by asserting
his own title. See, e.g., O. Holmes, The Common Law
98-100, 244-246 (1881). In any event, unlicensed use of property by
others is presumptively unjustified, as anyone who wishes to use
the property is free to bargain for the right to do so with the
property owner, cf. R. Posner, Economic Analysis of Law
10-13, 21 (1973). For these reasons, the law of trespass confers
protections from intrusion by others far broader than those
required by Fourth Amendment interests.

															JUSTICE WHITE, concurring in part and concurring in the
judgment.

															I concur in the judgment and join Parts 466 U.
S. S. 176|>II of the Court's opinion. These Parts
dispose of the issue before us; there is no need to go further and
deal with the expectation of privacy matter. However reasonable a
landowner's expectations of privacy may be, those expectations
cannot convert a field into a "house" or an "effect."

															JUSTICE MARSHALL, with whom JUSTICE BRENNAN and JUSTICE STEVENS
join, dissenting.

															In each of these consolidated cases, police officers, ignoring
clearly visible "No Trespassing" signs, entered upon private land
in search of evidence of a crime. At a spot that could Page 466 U. S. 185 not be seen from any vantage point accessible to the public, the
police discovered contraband, which was subsequently used to
incriminate the owner of the land. In neither case did the police
have a warrant authorizing their activities.

															The Court holds that police conduct of this sort does not
constitute an "unreasonable search" within the meaning of the
Fourth Amendment. The Court reaches that startling conclusion by
two independent analytical routes. First, the Court argues that,
because the Fourth Amendment, by its terms, renders people secure
in their "persons, houses, papers, and effects," it is inapplicable
to trespasses upon land not lying within the curtilage of a
dwelling. Ante at 466 U. S. 176 -177. Second, the Court contends that "an
individual may not legitimately demand privacy for activities
conducted out of doors in fields, except in the area immediately
surrounding the home." Ante at 466 U. S. 178 .
Because I cannot agree with either of these propositions, I
dissent. I The first ground on which the Court rests its decision is that
the Fourth Amendment "indicates with some precision the places and
things encompassed by its protections," and that real property is
not included in the list of protected spaces and possessions. Ante at 466 U. S. 176 .
This line of argument has several flaws. Most obviously, it is
inconsistent with the results of many of our previous decisions,
none of which the Court purports to overrule. For example, neither
a public telephone booth nor a conversation conducted therein can
fairly be described as a person, house, paper, or effect, [ Footnote 2/1 ] yet we have held that the
Fourth Amendment forbids the police without a warrant to eavesdrop
on such a conversation. Katz v. United States, 389 U. S. 347 (1967). Nor can it plausibly Page 466 U. S. 186 be argued that an office or commercial establishment is covered
by the plain language of the Amendment; yet we have held that such
premises are entitled to constitutional protection if they are
marked in a fashion that alerts the public to the fact that they
are private. Marshall v. Barlow's, Inc., 436 U.
S. 307 , 436 U. S. 311 (1978); G. M. Leasing Corp. v. United States, 429 U.
S. 338 , 429 U. S.
358 -359 (1977). [ Footnote
2/2 ]

															Indeed, the Court's reading of the plain language of the Fourth
Amendment is incapable of explaining even its own holding in this
case. The Court rules that the curtilage, a zone of real property
surrounding a dwelling, is entitled to constitutional protection. Ante at 466 U. S. 180 .
We are not told, however, whether the curtilage is a "house" or an
"effect" -- or why, if the curtilage can be incorporated into the
list of things and spaces shielded by the Amendment, a field
cannot.

															The Court's inability to reconcile its parsimonious reading of
the phrase "persons, houses, papers, and effects" with our prior
decisions, or even its own holding, is a symptom of a more
fundamental infirmity in the Court's reasoning. The Fourth
Amendment, like the other central provisions of the Bill of Rights
that loom large in our modern jurisprudence, was designed not to
prescribe with "precision" permissible and impermissible
activities, but to identify a fundamental human liberty that should
be shielded forever from government intrusion. [ Footnote 2/3 ] We do not construe constitutional
provisions Page 466 U. S. 187 of this sort the way we do statutes, whose drafters can be
expected to indicate with some comprehensiveness and exactitude the
conduct they wish to forbid or control and to change those
prescriptions when they become obsolete. [ Footnote 2/4 ] Rather, we strive, when interpreting these
seminal constitutional provisions, to effectuate their purposes --
to lend them meanings that ensure that the liberties the Framers
sought to protect are not undermined by the changing activities of
government officials. [ Footnote
2/5 ]

															The liberty shielded by the Fourth Amendment, as we have often
acknowledged, is freedom "from unreasonable government intrusions
into . . . legitimate expectations of privacy." United States
v. Chaduck, 433 U. S. 1 , 433 U. S. 7 (1977). That freedom would be incompletely protected if only
government conduct that impinged upon a person, house, paper, or
effect were subject to constitutional scrutiny. Accordingly, we
have repudiated the proposition that the Fourth Amendment applies
only to a limited set of locales or kinds of property. In Katz
v. United States, we expressly rejected a proffered locational
theory of the coverage of the Amendment, holding that it "protects
people, not places." 389 U.S. at 389 U. S. 351 .
Since that time, we have consistently adhered Page 466 U. S. 188 to the view that the applicability of the provision depends
solely upon

															"whether the person invoking its protection can claim a
'justifiable,' a 'reasonable,' or a 'legitimate expectation of
privacy' that has been invaded by government action." Smith v. Maryland, 442 U. S. 735 , 442 U. S. 740 (1979). [ Footnote 2/6 ] The Court's
contention that, because a field is not a house or effect, it is
not covered by the Fourth Amendment is inconsistent with this line
of cases, and with the understanding of the nature of
constitutional adjudication from which it derives. [ Footnote 2/7 ] II The second ground for the Court's decision is its contention
that any interest a landowner might have in the privacy of his
woods and fields is not one that "society is prepared to recognize
as reasonable.'" Ante at 466 U. S. 177 (quoting Katz v. United States, 389 U.S. at 389 U. S. 361 (Harlan, J., concurring)). Page 466 U. S. 189 The mode of analysis that underlies this assertion is certainly
more consistent with our prior decisions than that discussed above.
But the Court's conclusion cannot withstand scrutiny.

															As the Court acknowledges, we have traditionally looked to a
variety of factors in determining whether an expectation of privacy
asserted in a physical space is "reasonable." Ante at 466 U. S.
177 -178. Though those factors do not lend themselves to
precise taxonomy, they may be roughly grouped into three
categories. First, we consider whether the expectation at issue is
rooted in entitlements defined by positive law. Second, we consider
the nature of the uses to which spaces of the sort in question can
be put. Third, we consider whether the person claiming a privacy
interest manifested that interest to the public in a way that most
people would understand and respect. [ Footnote 2/8 ] When the expectations of privacy asserted
by petitioner Oliver and respondent Thornton [ Footnote 2/9 ] are examined through these lenses, it
becomes clear that those expectations are entitled to
constitutional protection. A We have frequently acknowledged that privacy interests are not
coterminous with property rights. E.g., United States v.
Salvucci, 448 U. S. 83 , 448 U. S. 91 (1980). However, because

															"property rights reflect society's explicit recognition Page 466 U. S. 190 of a person's authority to act as he wishes in certain areas,
[they] should be considered in determining whether an individual's
expectations of privacy are reasonable." Rakas v. Illinois, 439 U. S. 128 , 439 U. S. 153 (1978) (POWELL, J., concurring). [ Footnote 2/10 ] Indeed, the Court has suggested that,
insofar as

															"[o]ne of the main rights attaching to property is the right to
exclude others, . . . one who owns or lawfully possesses or
controls property will, in all likelihood, have a legitimate
expectation of privacy by virtue of this right to exclude." Id. at 439 U. S. 144 ,
n. 12 (opinion of the Court). [ Footnote 2/11 ]

															It is undisputed that Oliver and Thornton each owned the land
into which the police intruded. That fact alone provides
considerable support for their assertion of legitimate privacy
interests in their woods and fields. But even more telling is the
nature of the sanctions that Oliver and Thornton could invoke,
under local law, for violation of their property rights. In
Kentucky, a knowing entry upon fenced or otherwise enclosed land,
or upon unenclosed land conspicuously posted with signs excluding
the public, constitutes criminal trespass. Ky.Rev.Stat. §§
511.070(1), 511.080, 511.090(4) (1975). The law in Maine is
similar. An intrusion into

															"any place from Page 466 U. S. 191 which [the intruder] may lawfully be excluded and which is
posted in a manner prescribed by law or in a manner reasonably
likely to come to the attention of intruders or which is fenced or
otherwise enclosed"

															is a crime. Me.Rev.Stat.Ann., Tit. 17A, § 402(1)(C) (1964).
[ Footnote 2/12 ] Thus, positive
law not only recognizes the legitimacy of Oliver's and Thornton's
insistence that strangers keep off their land, but subjects those
who refuse to respect their wishes to the most severe of penalties
-- criminal liability. Under these circumstances, it is hard to
credit the Court's assertion that Oliver's and Thornton's
expectations of privacy were not of a sort that society is prepared
to recognize as reasonable. B The uses to which a place is put are highly relevant to the
assessment of a privacy interest asserted therein. Rakas v.
Illinois, supra, at 439 U. S. 153 (POWELL, J., concurring). If, in light of our shared sensibilities,
those activities are of a kind in which people should be able to
engage without fear of intrusion by private persons or government
officials, we extend the protection of the Fourth Amendment to the
space in question, even in the absence of any entitlement derived
from positive law. E.g., Katz v. United States, 389 U.S.
at 389 U. S.
352 -353. [ Footnote
2/13 ] Page 466 U. S. 192 Privately owned woods and fields that are not exposed to public
view regularly are employed in a variety of ways that society
acknowledges deserve privacy. Many landowners like to take solitary
walks on their property, confident that they will not be confronted
in their rambles by strangers or policemen. Others conduct
agricultural businesses on their property. [ Footnote 2/14 ] Some landowners use their secluded
spaces to meet lovers, others to gather together with fellow
worshippers, still others to engage in sustained creative endeavor.
Private land is sometimes used as a refuge for wildlife, where
flora and fauna are protected from human intervention of any kind.
[ Footnote 2/15 ] Our respect for
the freedom of landowners to use Page 466 U. S. 193 their posted "open fields" in ways such as these partially
explains the seriousness with which the positive law regards
deliberate invasions of such spaces, see supra at 466 U. S.
190 -191, and substantially reinforces the landowners'
contention that their expectations of privacy are "reasonable." C Whether a person "took normal precautions to maintain his
privacy" in a given space affects whether his interest is one
protected by the Fourth Amendment. Rawlings v. Kentucky, 448 U. S. 98 , 448 U. S. 105 (1980). [ Footnote 2/16 ] The
reason why such precautions are relevant is that we do not insist
that a person who has a right to exclude others exercise that
right. A claim to privacy is therefore strengthened by the fact
that the claimant somehow manifested to other people his desire
that they keep their distance.

															Certain spaces are so presumptively private that signals of this
sort are unnecessary; a homeowner need not post a "Do Not Enter"
sign on his door in order to deny entrance to uninvited guests.
[ Footnote 2/17 ] Privacy interests
in other spaces are more ambiguous, and the taking of precautions
is consequently more important; placing a lock on one's footlocker
strengthens one's claim that an examination of its contents is
impermissible. See United States v. Chaduck, 433 U.S. at 433 U. S. 11 .
Still other spaces are, by positive law and social convention,
presumed accessible to members of the public unless the
owner manifests his intention to exclude them.

															Undeveloped land falls into the last-mentioned category. If a
person has not marked the boundaries of his fields or woods in a
way that informs passersby that they are not welcome, Page 466 U. S. 194 he cannot object if members of the public enter onto the
property. There is no reason why he should have any greater rights
as against government officials. Accordingly, we have held that an
official may, without a warrant, enter private land from which the
public is not excluded and make observations from that vantage
point. Air Pollution Variance Board v. Western Alfalfa
Corp., 416 U. S. 861 , 416 U. S. 865 (1974). Fairly read, the case on which the majority so heavily
relies, Hester v. United States, 265 U. S.
57 (1924), affirms little more than the foregoing
unremarkable proposition. From aught that appears in the opinion in
that case, the defendants, fleeing from revenue agents who had
observed them committing a crime, abandoned incriminating evidence
on private land from which the public had not been excluded. Under
such circumstances, it is not surprising that the Court was
unpersuaded by the defendants' argument that the entry onto their
fields by the agents violated the Fourth Amendment. [ Footnote 2/18 ]

															A very different case is presented when the owner of undeveloped
land has taken precautions to exclude the public. As indicated
above, a deliberate entry by a private citizen onto private
property marked with "No Trespassing" signs will expose him to
criminal liability. I see no reason why a government official
should not be obliged to respect such Page 466 U. S. 195 unequivocal and universally understood manifestations of a
landowner's desire for privacy. [ Footnote 2/19 ]

															In sum, examination of the three principal criteria we have
traditionally used for assessing the reasonableness of a person's
expectation that a given space would remain private indicates that
interests of the sort asserted by Oliver and Thornton are entitled
to constitutional protection. An owner's right to insist that
others stay off his posted land is firmly grounded in positive law.
Many of the uses to which such land may be put deserve privacy.
And, by marking the boundaries of the land with warnings that the
public should not intrude, the owner has dispelled any ambiguity as
to his desires.

															The police in these cases proffered no justification for their
invasions of Oliver's and Thornton's privacy interests; in neither
case was the entry legitimated by a warrant or by one of the
established exceptions to the warrant requirement. I conclude,
therefore, that the searches of their land violated the Fourth
Amendment, and the evidence obtained in the course of those
searches should have been suppressed. III A clear, easily administrable rule emerges from the analysis set
forth above: private land marked in a fashion sufficient to render
entry thereon a criminal trespass under the law of the State in
which the land lies is protected by the Fourth Amendment's
proscription of unreasonable searches and seizures. One of the
advantages of the foregoing rule is that Page 466 U. S. 196 it draws upon a doctrine already familiar to both citizens and
government officials. In each jurisdiction, a substantial body of
statutory and case law defines the precautions a landowner must
take in order to avail himself of the sanctions of the criminal
law. The police know that body of law, because they are entrusted
with responsibility for enforcing it against the public; it
therefore would not be difficult for the police to abide by it
themselves.

															By contrast, the doctrine announced by the Court today is
incapable of determinate application. Police officers, making
warrantless entries upon private land, will be obliged in the
future to make on-the-spot judgments as to how far the curtilage
extends, and to stay outside that zone. [ Footnote 2/20 ] In addition, we may expect to see a
spate of litigation over the question of how much improvement is
necessary to remove private land from the category of "unoccupied
or undeveloped area" to which the "open fields exception" is now
deemed applicable. See ante at 466 U. S. 180 ,
n. 11.

															The Court's holding not only ill-serves the need to make
constitutional doctrine "workable for application by rank-and-file,
trained police officers," Illinois v. Andreas, 463 U. S. 765 , 463 U. S. 772 (1983), it withdraws the shield of the Fourth Amendment from
privacy interests that clearly deserve protection. By exempting
from the coverage of the Amendment large areas of private land, the
Court opens the way to investigative activities we would all find
repugnant. Cf., e.g., United States v. Lace, 669 F.2d 46,
54 (CA2 1982) (Newman, J., concurring in result) ("[W]hen police
officers execute military maneuvers on residential property for
three weeks of round-the-clock surveillance, can that be called reasonable'?"); Page 466 U. S.
197 State v. Brady, 406 So. 2d
1093 , 1094-1095 (Fla. 1981) ("In order to position surveillance
groups around the ranch's airfield, deputies were forced to cross a
dike, ram through one gate and cut the chain lock on another, cut
or cross posted fences, and proceed several hundred yards to their
hiding places"), cert. granted, 456 U.S. 988, supplemental
memoranda ordered and oral argument postponed, 459 U.S. 986 (1982).
[ Footnote 2/21 ] The Fourth Amendment, properly construed, embodies and gives
effect to our collective sense of the degree to which men and
women, in civilized society, are entitled "to be let alone" by
their governments. Olmstead v. United States, 277 U.
S. 438 , 277 U. S. 478 (1928) (Brandeis, J., dissenting); cf. Smith v. Maryland, 442 U.S. at 442 U. S. 750 (MARSHALL, J., dissenting). The Court's opinion bespeaks and will
help to promote an impoverished vision of that fundamental
right.

															I dissent.

															[ Footnote 2/1 ]

															The Court informs us that the Framers would have understood the
term "effects" to encompass only personal property. Ante at 466 U. S. 177 ,
n. 7. Such a construction of the term would exclude both a public
phone booth and spoken words.

															[ Footnote 2/2 ]

															On the other hand, an automobile surely does constitute an
"effect." Under the Court's theory, cars should therefore stand on
the same constitutional footing as houses. Our cases establish,
however, that car owners' diminished expectations that their cars
will remain free from prying eyes warrants a corresponding
reduction in the constitutional protection accorded cars. E.g.,
United States v. Martinez-Fuerte, 428 U.
S. 543 , 428 U. S. 561 (1976).

															[ Footnote 2/3 ]

															By their terms, the provisions of the Bill of Rights curtail
only activities by the Federal Government, See Barron v.
Mayor and City Council of Baltimore , 7 Pet. 243
(1833), but the Fourteenth Amendment subjects state and local
governments to the most important of those restrictions, see,
e.g., Cantwell v. Connecticut, 310 U.
S. 296 (1940) (First Amendment); Wolf v.
Colorado, 338 U. S. 25 (1949)
(Fourth Amendment).

															[ Footnote 2/4 ] Cf. 17 U. S. Maryland, 4 Wheat. 316, 17 U. S. 407 (1819) ("[W]e must never forget, that it is a constitution we are expounding." Such a document cannot be as detailed as a
"legal code"; "[i]ts nature . . . requires, that only its great
outlines should be marked, its important objects designated, and
the minor ingredients which compose those objects be deduced from
the nature of the objects themselves") (emphasis in original).

															[ Footnote 2/5 ]

															Our rejection of the mode of interpretation appropriate for
statutes is perhaps clearest in our treatment of the First
Amendment. That Amendment provides, in pertinent part, that
"Congress shall make no law . . . abridging the freedom of speech,
or of the press," but says nothing, for example, about restrictions
on expressive behavior or about access to the courts. Yet, to give
effect to the purpose of the Amendment, we have applied it to
regulations of conduct designed to convey a message, e.g.,
Edwards v. South Carolina, 372 U. S. 229 (1963), and have accorded constitutional protection to the public's
"right of access to criminal trials," Globe Newspaper Co. v.
Superior Court, 457 U. S. 596 , 457 U. S.
604 -605 (1982).

															[ Footnote 2/6 ] See also United States v. Chadwick, 433 U. S.
1 , 433 U. S. 7 , 11
(1977) (disagreeing with the suggestion that the Fourth Amendment
"protects only dwellings and other specifically designated
locales"; asserting instead that the purpose of the Amendment "is
to safeguard individuals from unreasonable government invasions of
legitimate privacy interests"); Rakas v. Illinois, 439 U. S. 128 , 439 U. S. 143 (1978) (holding that the determinative question is "whether the
person who claims the protection of the Amendment has a legitimate
expectation of privacy in the invaded place").

															Our most recent decisions continue to rely on the conception of
the purpose and scope of the Fourth Amendment that we enunciated in Katz. See, e.g., United States v. Jacobsen, ante at 466 U. S.
113 -118; Michigan v. Clifford, 464 U.
S. 287 , 464 U. S.
292 -293 (1984); Illinois v. Andreas, 463 U. S. 765 , 463 U. S. 771 (1983); United States v. Place, 462 U.
S. 696 , 462 U. S.
706 -707 (1983); Texas v. Brown, 460 U.
S. 730 , 460 U. S.
738 -740 (1983) (plurality opinion); United States v.
Knotts, 460 U. S. 276 , 460 U. S.
280 -281 (1983).

															[ Footnote 2/7 ]

															Sensitive to the weakness of its argument that the "persons or
things" mentioned in the Fourth Amendment exhaust the coverage of
the provision, the Court goes on to analyze at length the privacy
interests that might legitimately be asserted in "open fields." The
inclusion of Parts 466 U. S. S.
182|>IV in the opinion, coupled with the Court's reaffirmation
of Katz and its progeny, ante at 466 U. S. 177 ,
strongly suggests that the plain language theory sketched in 466 U. S. [ Footnote 2/8 ]

															The privacy interests protected by the Fourth Amendment are not
limited to expectations that physical areas will remain free from
public and government intrusion. See supra at 466 U. S.
187 -188. The factors relevant to the assessment of the
reasonableness of a nonspatial privacy interest may well be
different from the three considerations discussed here. See,
e.g., Smith v. Maryland, 442 U. S. 735 , 442 U. S.
747 -748 (1979) (Stewart, J., dissenting); id. at 442 U. S.
750 -752 (MARSHALL, J., dissenting).

															[ Footnote 2/9 ]

															The Court does not dispute that Oliver and Thornton had
subjective expectations of privacy, nor could it in view of the
lower courts' findings on that issue. See United States v.
Oliver, No. CR80-00005-01-BG (WD Ky., Nov. 14, 1980), App. to
Pet. for Cert. in No. 82-15, pp.19-20; Maine v. Thornton, No. CR82-10 (Me.Super.Ct., Apr. 16, 1982), App. to Pet. for Cert.
in No. 82-1273, pp. B-4 - B-5.

															[ Footnote 2/10 ]

															The Court today seeks to evade the force of this principle by
contending that the law of property is designed to serve various
"prophylactic" and "economic" purposes unrelated to the protection
of privacy. Ante at 466 U. S.
183 -184, and n. 15. Such efforts to rationalize the
distribution of entitlements under state law are interesting and
may have some explanatory power, but cannot support the weight the
Court seeks to place upon them. The Court surely must concede that
one of the purposes of the law of real property (and specifically
the law of criminal trespass, see infra, this page and 466 U. S. 191 ,
and n. 12) is to define and enforce privacy interests -- to empower
some people to make whatever use they wish of certain tracts of
land without fear that other people will intrude upon their
activities. The views of commentators, old and new, as to other
functions served by positive law are thus insufficient to support
the Court's sweeping assertion that, "in the case of open fields,
the general rights of property . . . have little or no relevance to
the applicability of the Fourth Amendment," ante at 466 U. S.
183 -184.

															[ Footnote 2/11 ] See also Rawlings v. Kentucky, 448 U. S.
98 , 448 U. S. 112 (1980) (BLACKMUN, J., concurring).

															[ Footnote 2/12 ] Cf. Comment to ALI, Model Penal Code § 221.2, p. 87
(1980) ("The common thread running through these provisions [a
sample of state criminal trespass laws] is the element of unwanted
intrusion, usually coupled with some sort of notice to would-be
intruders that they may not enter. Most people do not object to
strangers tramping through woodland or over pasture or open range.
On the other hand, intrusions into buildings, onto property fenced
in a manner manifestly designed to exclude intruders, or onto any
private property in defiance of actual notice to keep away is
generally considered objectionable, and under some circumstances
frightening").

															[ Footnote 2/13 ]

															In most circumstances, this inquiry requires analysis of the
sorts of uses to which a given space is susceptible, not the manner
in which the person asserting an expectation of privacy in the
space was in fact employing it. See, e.g., United States v.
Chadwick, 433 U.S. at 433 U. S. 13 . We make exceptions to this principle and
evaluate uses on a case-by-case basis in only two contexts: when
called upon to assess (what formerly was called) the "standing" of
a particular person to challenge an intrusion by government
officials into a area over which that person lacked primary
control, see, e.g., Rakas v. Illinois, 439 U.S. at 439 U. S.
148 -149; Jones v. United States, 362 U.
S. 257 , 362 U. S.
265 -266 (1960), and when it is possible to ascertain how
a person is using a particular space without violating the very
privacy interest he is asserting, see, e.g., Katz v. United
States, 389 U.S. at 389 U. S. 352 .
(In cases of the latter sort, the inquiries described in this Part
and in 466 U. S. infra, are coextensive). Neither of these exceptions is
applicable here. Thus, the majority's contention that, because the
cultivation of marihuana is not an activity that society wishes to
protect, Oliver and Thornton had no legitimate privacy interest in
their fields, ante at 466 U. S.
182 -183, and n. 13, reflects a misunderstanding of the
level of generality on which the constitutional analysis must
proceed.

															[ Footnote 2/14 ]

															We accord constitutional protection to businesses conducted in
office buildings, see supra at 466 U. S.
185 -186; it is not apparent why businesses conducted in
fields that are not open to the public are less deserving of the
benefit of the Fourth Amendment.

															[ Footnote 2/15 ]

															This last-mentioned use implicates a kind of privacy interest
somewhat different from those to which we are accustomed. It
involves neither a person's interest in immunity from observation
nor a person's interest in shielding from scrutiny the residues and
manifestations of his personal life. Cf. Weinreb,
Generalities of the Fourth Amendment, 42 U.Chi.L.Rev. 47, 52-54
(1974). It derives, rather, from a person's desire to preserve
inviolate a portion of his world. The idiosyncracy of this interest
does not, however, render it less deserving of constitutional
protection.

															[ Footnote 2/16 ] See also Rakas v. Illinois, supra, at 439 U. S. 152 (POWELL, J., concurring); United States v. Chadwick,
supra, at 433 U. S. 11 ; Katz v. United States, supra, at 389 U. S.
352 .

															[ Footnote 2/17 ]

															However, if the homeowner acts affirmatively to invite someone
into his abode, he cannot later insist that his privacy interests
have been violated. Lewis v. United States, 385 U.
S. 206 (1966).

															[ Footnote 2/18 ]

															An argument supportive of the position taken by the Court today
might be constructed on the basis of an examination of the record
in Hester. It appears that, in his approach to the house,
one of the agents crossed a pasture fence. See Tr. of
Record in Hester v. United States, O.T. 1923, No. 243, p.
16. However, the Court, in its opinion, placed no weight upon --
indeed, did not even mention -- that circumstance.

															In any event, to the extent that Hester may be read to
support a rule any broader than that stated in Air Pollution
Variance Board v. Western Alfalfa Corp., 416 U.
S. 861 (1974), it is undercut by our decision in Katz, which repudiated the locational theory of the
coverage of the Fourth Amendment enunciated in Olmstead v.
United States, 277 U. S. 438 (1928), and by the line of decisions originating in Katz, see
supra at 466 U. S.
187 -188, and n. 6.

															[ Footnote 2/19 ]

															Indeed, important practical considerations suggest that the
police should not be empowered to invade land closed to the public.
In many parts of the country, landowners feel entitled to use
self-help in expelling trespassers from their posted property.
There is thus a serious risk that police officers, making
unannounced, warrantless searches of "open fields," will become
involved in violent confrontations with irate landowners, with
potentially tragic results. Cf. McDonald v. United States, 335 U. S. 451 , 335 U. S.
460 -461 (1948) (Jackson, J., concurring).

															[ Footnote 2/20 ]

															The likelihood that the police will err in making such judgments
is suggested by the difficulty experienced by courts when trying to
define the curtilage of dwellings. See, e.g., United States v.
Berrong, 712 F.2d 1370, 1374, and n. 7 (CA11 1983), cert.
pending, No. 83-988, United States v. Van Dyke, 643
F.2d 992, 993-994 (CA4 1981).

															[ Footnote 2/21 ]

															Perhaps the most serious danger in the decision today is that,
if the police are permitted routinely to engage in such behavior,
it will gradually become less offensive to us all. As Justice
Brandeis once observed:

															"Our Government is the potent, the omnipresent teacher. For good
or for ill, it teaches the whole people by its example. Crime is
contagious. If the Government becomes a lawbreaker, it breeds
contempt for law. . . ." Olmstead v. United States, 277 U.S. at 277 U. S. 485 (dissenting opinion). See also Solem v. Stumes, 465 U. S. 638 , 465 U. S. 667 (1984) (STEVENS, J., dissenting).

Summary: In these two cases, the Supreme Court applied the "open fields doctrine," which allows police officers to enter and search fields without a warrant if they are open to the public, even if they are posted with "No Trespassing" signs. The Court held that the discovery of marijuana fields in both cases was valid under this doctrine, as the fields were not considered "effects" under the Fourth Amendment, which protects against unreasonable searches and seizures.