RAY E. OLIVER, PETITIONER V. UNITED STATES OF AMERICA

   No. 82-15

   In the Supreme Court of the United States

   October Term, 1982

   On Writ of Certiorari to the United States Court of Appeals for the
Sixth Curcuit

   Brief for the United States

            TABLE OF CONTENTS
   Opinions 0elow
   Jurisdiction
   Statement
   Summary of argument
   Argument:
      The Fourth Amendment does not require a warrant based upon
      probable cause as a precondition to entry onto a field
      A. The open fields doctrine retains its vitality today
      B. The open fields doctrine may apply to fields that are
          posted and fenced
          1. Petitioner's posting of signs and erection of a gate did
             not convert his open field into an area in which he had a
             legitimate expectation of privacy
          2. Petitioner's ownership of his open field did not create a
             presumption of a legitimate expectation of privacy
      C. Even assuming privately owned woods or fields are in some
          circumstances entitled to Fourth Amendment protection, a
          warrantless search on the basis of reasonable suspicion of
          criminal activity is permitted
   Conclusion

                            OPINIONS BELOW

   The opinion of the en banc court of appeals (Pet. App. 31-66) is
reported at 686 F.2d 356.  The opinion of the panel (Pet. App. 25-30)
is reported at 657 F.2d 85.  The opinion of the district court (Pet.
App. 21-24) is not reported.

                             JURISDICTION

   The judgment of the en banc court of appeals (Pet. App. 67) was
entered on May 5, 1982.  The petition for a writ of certiorari was
filed on July 2, 1982, and was granted on January 24, 1983.  The
jurisdiction of this Court is invoked under 28 U.S.C. 1254(1).

                          QUESTION PRESENTED

   Whether the warrantless entry by police onto petitioner's fenced
and posted field by way of an unobstructed footpath violated the
Fourth Amendment.

                               STATEMENT

   Petitioner was indicted in the United States District Court for the
Western District of Kentucky for manufacturing marijuana, in violation
of 21 U.S.C. 841(a).  Prior to trial, he moved to suppress evidence
obtained from a warrantless search of his property, and the district
court granted the motion (Pet. App. 21-24).  A panel of the court of
appeals affirmed (id. at 25-30).  The full court subsequently granted
the government's petition for rehearing en banc and reversed the
suppression order (id. at 31-66.)

   1. The evidence adduced at the suppression hearing established that
on July 18, 1980, an anonymous informant advised a Kentucky state
police officer that petitioner was growing marijuana on his farm.  The
officer had heard other reports in the community to the effect that
petitioner was engaged in some kind of questionable activity on his
farm, so the officer, joined by a second detective, drove to
petitioner's farm to investigate (J.A. 2-3).

   When the officers arrived at the farm, they drove down a road past
petitioner's house to a point about three-quarters of a mile from the
house at which they encountered a locked gate with a "No Trespassing"
sign.  While the gate precluded vehicular access, there was no fence
at one end of the gate, and there was a path around the gate at that
point, which the officers followed (J.A. 3, 5, 16, 22, 23).  They had
walked several hundred yards along the road on the other side of the
gate when they heard someone yelling at them from a distance that
there was no hunting allowed.  They announced that they were police
officers and walked towards the place where they had heard the person
shouting at them.  When they arrived there, however, they did not find
anyone (J.A. 3-4).  The officers then returned to the road, walked
some distance farther down the road, and discovered a large field full
of marijuana (J.A. 4).  The officers subsequently arrested petitioner
for manufacturing a controlled substance, and, after further inquiries
by the officers prompted by a neighbor's statement, petitioner
eventually led them to a second marijuana field (J.A. 10-11).  The
fields had allegedly been leased by petitioner to two other persons
for six months (J.A. 9, 32-35).

   2. The district court suppressed the evidence of the discovery of
the marijuana (Pet. App. 21-24).  The court noted that the gate across
the road was locked, that the property was posted with "No
Trespassing" signs, and that the fields where the marijuana was
located were in a secluded part of the farm (id. at 22).  /1/ On the
basis of these factors, the district court concluded that petitioner
had a reasonable expectation of privacy in the area where the
marijuana was discovered and that, because the officers had entered
that area without a warrant, the discovery of the marijuana would not
be admissible at trial.

   A panel of the court of appeals affirmed the suppression order
(Pet. App. 25-30).  The panel noted that under the "open fields"
doctrine of Hester v. United States, 265 U.S. 57 (1924), warrantless
searches are permitted of any area outside private residences and the
"curtilage" around those residences and that the field searched here
was not within the curtilage (Pet. App. 27-28).  The panel concluded,
however, that the Hester decision had been undercut by this Court's
subsequent decision in Katz v. United States, 389 U.S. 347 (1967),
which held that Fourth Amendment rights generally turn on the presence
of a legitimate expectation of privacy, not on distinctions in
property concepts (Pet. App. 28).  On the facts of this case, the
panel held, petitioner had a reasonable expectation of privacy in the
field where the marijuana was growing because the field was located on
the other side of a locked gate marked with "No Trespassing" signs
(id. at 28-29).  Because the Sixth Circuit's prior decision in United
States v. Hassell, 336 F.2d 684 (1964), cert. denied, 380 U.S. 965
(1965), relied on the Hester "open fields" doctrine, the panel
declared that Hassell is "no longer the law of this circuit" (Pet.
App. 30).

   3. On rehearing en banc, a majority of the full court disagreed
with the panel's conclusion that Hester had been undercut by Katz.
The court noted that while this Court had been called upon in Katz to
apply the Fourth Amendment to circumstances -- the monitoring of a
telephone conversation -- "that could not have been contemplated at
the time the Amendment was formulated and adopted", the open fields
doctrine of Hester simply made a distinction that was "'as old as the
common law'" (Pet. App. 34-35).  The court also observed that there
were indications in the Katz opinion itself that the Hester doctrine
was still considered valid (id. at 35-36), and that this Court had on
several occasions since Katz referred to Hester without ever
suggesting that its principles had been diluted (id. at 37).  The
court explained that the requirements of the Fourth Amendment did not
apply here because "(t)he human relations that create the need for
privacy do not ordinarily take place in (an open field)" (id. at 38).
The court concluded that any expectation of privacy that a property
owner might have in his open field was, as a matter of law, not one
that society is prepared to recognize as reasonable (id. at 36).

   Chief Judge Edwards and Judges Keith, Lively, and Jones dissented
(Pet. App. 38-65), contending that the open fields doctrine of Hester
applies only to areas from which the public is not excluded or to an
object or activity that is exposed to public view (id. at 52-53).
Because they concluded that petitioner had taken measures to exclude
the public from his property that gave rise to a reasonable
expectation of privacy, the dissenters expressed the view that the
open fields doctrine did not permit the entry onto petitioner's field
(id. at 60-65).  The dissenters added that adherence to their view
would not unduly hamper law enforcement because police lawfully could
have used helicopters to observe the marijuana from the air (id. at
63-64).  Judge Lively wrote separately to express his view that this
case did not involve an "open field" at all within the meaning of
Hester (id. at 66).  summary OF ARGUMENT

                          SUMMARY of ARGUMENT

   A. In Hester v. United States, 265 U.S. 57, 59 (1924), this Court
held that "the special protection accorded by the Fourth Amendment to
the people in their 'persons, houses, papers, and effects,' is not
extended to the open fields." This rule was not undermined by this
Court's decision in Katz v. United States, 389 U.S. 347 (1967), which
held that warrantless wiretapping of a public telephone violated an
individual's legitimate expectation of privacy.  To the contrary, this
Court cited Hester with approval in Katz itself, and has done so in
subsequent decisions.  This is because the property interest that a
landowner has in his field is not equivalent to a privacy interest
that gives rise to Fourth Amendment protection.  Apart from the
curtilage surrounding a residence, an individual does not have an
expectation of privacy that society is prepared to recognize as
"reasonable" in an open field.

   B. Posting and fencing an open field does not necessarily alter its
character so as to create a protected Fourth Amendment privacy
interest in the field.  While posting a fence puts an outsider on
notice that he is about to commit a trespass, the facts of Hester make
clear that the "open fields" doctrine is based on the lack of privacy
expectation in the field and does not depend on whether or not the
police officer is aware that he is trespassing.  The posting of "No
Trespassing" signs, as a practical matter, gives a landowner little
assurance that outsiders will not enter his property;  indeed, state
statutes typically give law enforcement officials, such as game
wardens, specific authority to enter private posted lands to monitor
compliance with state wildlife laws.  See, e.g., Ky. Rev. Stat. Ann.
Sections 149.090, 150.090 (Bobbs-Merrill repl. 1980 & 1982 Cum.
Supp.).

   Nor does the existence of a fence surrounding an open field
necessarily increase the expectation of privacy in that field.  Fences
around large areas of rural property are usually designed to mark a
boundary or to keep animals in rather than to keep people out, and
they post little impediment to entry by a person.  Like posting, the
existance of such a fence does not give a landowner a reasonable
assurance that outsiders will not enter onto his land.  Accordingly,
the courts generally have held that there is no protected Fourth
Amendment privacy interest in a field that is surrounded by a
nonexclusionary fence.

   In the circumstances of this case, it is clear that petitioner, by
erecting a "No Trespassing" sign and a gate across the road, did not
convert his open field into an area protected by the Fourth Amendment.
 First, because petitioner leased his fields to other persons and
relinquished full control over them, he plainly had no expectation
that persons unknown to him would not enter past the sign and gate as
invitees of the lessee.  Moreover, it is undisputed that the gate
blocked only vehicular passage, and there was no physical impediment
to entry by foot;  indeed, the officers entered on a well-traveled
footpath.  Thus, the only basis for petitioner, or even the lessees,
to claim that the open field was converted into an area protected by
the Fourth Amendment is the notice of entry onto private property
provided by the posted signs.  That is an insufficient basis for a
landowner reasonably to expect that no outsider will enter his field.
Since Hester and Katz plainly establish that the fact of ownership
itself does not create a protected Fourth Amendment interest in a
field, the officers' entry onto petitioner's field was constitutional.

   C. A landowner may take more substantial measures to exclude
outsiders from his field, such as erecting a barrier effectively
designed to prevent entry by other persons.  Arguably, such action
would give him a reasonable expectation of some degree of privacy in
the field.  Even so (or even assuming that petitioner's contention is
accepted that mere posting of a field gives rise to a legitimate
expectation of privacy), that expectation of privacy is a limited one
that does not approach the privacy interest that an individual has in
his home or office, or even such areas of concededly reduced privacy
as his automobile.  Even a field surrounded by an exclusionary fence
is subject to observation from the air and thus cannot be regarded as
wholly private.  More important, if the police are mistaken in their
suspicion of criminal activity, their unjustified entry onto the field
is at most a minimal disruption of an individual's privacy;  the
officers will observe only what is ordinarily found in a field, such
as cornstalks and cows.  On the other hand, when police enter a home,
they intrude into the area that people reserve for their most personal
and private matters.

   The "reasonableness" of a search or a seizure under the Fourth
Amendment is judged "by balancing its intrusion on the individual's
Fourth Amendment interests against its promotion of legitimate
governmental interests." Delaware v. Prouse, 440 U.S. 648, 654 (1979)
(footnote omitted).  Because of the magnitude of the privacy invasion
involved in a search of a home, this Court has concluded that the
Fourth Amendment establishes two prerequisites to sustain the
reasonableness of such a search:  (1) the substantive standard for
balancing societal law enforcement against individual privacy
interests is probable cause;  (2) as a procedural protection to
minimize the risk of a mistake, probable cause is to be determined by
a neutral and detached magistrate.  In the case of an entry onto a
field, where any privacy intrusion is so greatly diminished, it is
reasonable that the prerequisites to such an entry be more relaxed, as
the Court has recognized in other contexts where there is a
substantially reduced privacy intrusion.  For example, the warrant
requirement does not apply to a search of an automobile, which is an
area of reduced privacy expectation.  See United States v. Chadwick,
433 U.S. 1, 12 (1977).  And police may effect brief investigatory
detentions on suspicion that does not amount to probable cause.  See,
e.g., Terry v. Ohio, 392 U.S. 1 (1968).  In a situation where police
have reason to suspect that evidence of criminal activity will be
found in a field -- even one in which the landowner has taken
effective measures to prevent entry by outsiders arguably justifying
recognition of some degree of privacy interest -- it is "reasonable"
within the meaning of the Fourth Amendment to enter the field on the
basis of a reasonable suspicion of criminal activity, given the
comparatively minor privacy intrusion entailed in the entry.  Thus,
even assuming arguendo that petitioner had some legitimate expectation
of privacy in his field, the officers' entry was constitutional
because it was based on information that gave them a reasonable
suspicion that criminal activity was afoot.

 ARGUMENT THE FOURTH AMENDMENT DOES NOT REQUIRE A WARRANT BASED UPON
PROBABLE CAUSE AS A PRECONDITION TO ENTRY ONTO A FIELD

        A. The Open Fields Doctrine Retains Its Vitality Today

   The "open fields" doctrine was first enunciated by this Court in
Hester v. United States, 265 U.S. 57 (1924).  In that case, two
revenue officers entered onto the defendant's property and, from a
distance of 50-100 yards from his house, saw the defendant hand
another person what appeared to be a gallon jug of illicitly distilled
whiskey.  The Court held, in a unanimous decision authored by Justice
Holmes, that the fact that the officers had trespassed on the
defendant's property was not a reason for suppressing the observations
made by the officers.  The Court explained (265 U.S. at 59):  "(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."

   While the Court's opinion in Hester is conclusory, it has become
the source of a well-entrenched rule of law, viz., that the open areas
beyond the house and its "curtilage" are not within those areas
protected by the Fourth Amendment.  /2/ This rule is soundly based in
the specific language of the Fourth Amendment and its limited
proscription of only those searches and seizures that are
"unreasonable."

   Petitioner contends (Br. 14-20) that this Court's decision in Katz
v. United States, 389 U.S. 347 (1967), "complete(ly) discredit(ed)"
(Br. 17) the open fields doctrine of Hester.  But there is nothing in
Katz to suggest repudiation of the basic principle of the open fields
doctrine.  In Katz, the Court simply held that the Fourth Amendment
protected private conversations conducted in a public telephone booth
against warrantless wiretapping.  To be sure, Katz recognizes that the
Fourth Amendment may extend to an area that is not within the
curtilage of a privately-owned building, but it does so in the
specific context of electronic surveillance of a private telephone
conversation;  it certainly does not suggest extension of Fourth
Amendment protection to an open area like a field, /3/ even if an
individual may prefer that his activity there remain private.  /4/

   Indeed, both the majority opinion in Katz and Justice Harlan's
oft-cited concurring opinion, each of which is relied upon by
petitioner (Br. 18-19) and by the dissent below (Pet. App. 48-50),
discuss Hester approvingly.  Citing Hester, the Court noted in Katz
that "(i)t appears to be common ground * * * that an open field is not
(an area protected by the Fourth Amendment)." 389 U.S. at 351 n.8.
Justice Harlan stated that a "telephone booth is an area where, like a
home, * * * and unlike a field (citing Hester), a person has a
constitutionally protected reasonable expectation of privacy." Id. at
360 (emphasis added).  See also id. at 361.  Moreover, since Katz this
Court has relied on Hester and consistently cited it approvingly in
other decisions.  See Air Pollution Variance Board v. Western Alfalfa
Corp., 416 U.S. 861, 865-866 (1974);  see also United States v.
Knotts, No. 81-1802 (Mar. 2, 1983), slip op. 6, 9;  Rakas v. Illinois,
439 U.S. 128, 144 n.12 (1978);  G.M. Leasing Corp. v. United States,
429 U.S. 338, 352 (1977);  United States v. Santana, 427 U.S. 38, 42
(1976);  Cady v. Dombrowski, 413 U.S. 433, 450 (1973);  Bivens v. Six
Unknown Named Agents of Federal Bureau of Narcotics, 403 U.S. 388, 393
n.6 (1971).

   An examination of the reasoning of Katz also makes clear that it
casts no doubt on the continuing vitality of Hester.  Katz holds that
the Fourth Amendment protects areas where an individual has a
"justifiabl(e)" expectation of privacy.  389 U.S. at 353.  Justice
Harlan's concurring opinion amplifies this concept by suggesting a
two-part inquiry to determine whether an area is protected by the
Fourth Amendment (389 U.S. at 361) -- whether the individual, by his
conduct, has exhibited a subjective expectation of privacy;  and
whether that expectation is "one that society is prepared to recognize
as 'reasonable'" -- and the Court generally has adopted this
formulation as embodying the Katz rationale.  See United States v.
Knotts, supra, slip op. 4-5;  Smith v. Maryland, 442 U.S. 735, 740
(1979);  Rakas v. Illinois, supra, 439 U.S. at 143-144 n.12.  The
Court's holding in Hester, in terms of the Katz analysis, is simply
that society does not recognize as reasonable an expectation of
privacy in open fields, and nothing in Katz suggests that a different
rule should apply.

   Thus, the courts of appeals generally have recognized that Hester
retains its force after Katz as standing for the general proposition
that an individual ordinarily does not have a legitimate expectation
of privacy -- in particular, one that implicates the protections of
the Warrant Clause of the Fourth Amendment -- in an open field.  In
the words of the Ninth Circuit, Hester indicates that "open fields are
not areas in which one traditionally might reasonably expect privacy."
United States v. Freie, 545 F.2d 1217, 1223 (9th Cir. 1976), cert.
denied, 430 U.S. 966 (1977).  Thus, the court in Freie held that, even
if the owners had subjective expectations of privacy in their private
field surrounded by a fence, "those expectations were not objectively
reasonable." Ibid.  See also United States v. Williams, 581 F.2d 451,
453 (5th Cir. 1978), cert. denied, 440 U.S. 972 (1979);  Patler v.
Slayton, 503 F.2d 472, 478 (4th Cir. 1974);  S. Rep. No. 1097, 90th
Cong., 2d Sess. 90 (1968), quoted in United States v. Paul, 614 F.2d
115, 119 (6th Cir.) (Phillips, J., concurring), cert. denied, 446 U.S.
941 (1980) (post-Katz discussion of federal wiretapping statute noting
that expectation of privacy in an open field is "clearly
unjustified").

   It is true, of course, that unconsented entry onto open fields
often violates the landowner's property rights.  But Hester undeniably
stands for the proposition that a legal property interest is not
necessarily equivalent to an interest protected by the Fourth
Amendment, and the Court has consistently adhered to this view.  See
generally Rakas v. Illinois, supra, 439 U.S. at 143-144 n.12.  This
principle was not challenged in Katz;  indeed, it is Katz that
emphasizes that the Fourth Amendment focuses on legitimate privacy
interests and is not coextensive with property rights.  See 389 U.S.
at 351-353;  see also Payton v. New York, 445 U.S. 573, 591 n.33
(1980);  Rakas v. Illinois, supra, 439 U.S. at 151 (Powell, J.,
concurring).

   Thus, it is ironic, to say the least, that primary reliance is
placed upon Katz to argue that the Warrant Clause protects open fields
by virtue of an individual's ownership of those fields.  The fact that
Katz recognized the existence of a legitimate expectation of privacy
in a public place because of the peculiarly private nature of the
activity -- a phone conversation -- does not vitiate Hester in any
way.  To the contrary, Katz buttresses the rationale of the open
fields doctrine, namely, that an individual may lack a legitimate
expectation of privacy in an area like a field, where private
activities do not ordinarily take place, even if the field is private
property.

   It is undoubtedly true that an individual may have a strong
subjective expectation of privacy in activity he carries on in an open
field, depending on the distance of the field from areas frequented by
the public and the nature of the terrain (cf. Pet. Br. 23).  The
probability that another person will observe his activity "in the
middle of nowhere" is small.  But an individual has an analogous
expectation of privacy in activities undertaken late at night in an
apparently deserted alley or forest;  obviously, however, he can have
no constitutional objection if a policeman stumbles upon him when he
is engaged in criminal activity.  Clearly, then, an expectation of
privacy entitled to Fourth Amendment protection cannot be grounded
merely on the improbability of being observed.  In sum, both before
and after Katz, there is no basis for recognizing a legitimate
expectation of privacy in an open field, and hence there is no reason
to modify the traditional open fields doctrine here.  /5/

 B. The Open Fields Doctrine May Apply To Fields That Are Posted And
Fenced

 1. Petitioner's Posting of Signs and Erection of a Gate Did Not
Convert His Open Field Into an Area in Which He Had a Legitimate
Expectation of Privacy

   Petitioner contends (Br. 20-23), adopting the view of the dissent
(Pet. App. 50-53), that, to the extent it survives at all, the open
fields doctrine today is quite limited in scope:  it permits police to
observe objects that are exposed to the public and allows them to
conduct a warrantless search only in an area from which the public is
not excluded.  If an owner of property has manifested in any way that
his property is not open to the public, however -- for example, by
posting a sign -- petitioner contends that the police may not enter
except with a warrant based upon probable cause, irrespective of the
nature of the property and the degree to which the entry can
reasonably be expected to infringe upon the individual's privacy.
Because petitioner's field was posted and vehicular access blocked by
a gate across the road, he contends (Br. 23) that the warrantless
policy entry here violated the Fourth Amendment.  In the words of the
dissent, "the public was provided with more than adequate notice that
they were not to trepass on (petitioner's) farm";  therefore the
search "was not limited to areas of public access" and thus "not
within the narrow confines of the Open Fields Doctrine" (Pet. App.
62).

   This crabbed version of the open fields doctrine misperceives the
principles underlying the Fourth Amendment and, moreover, cannot be
squared with the holding in Hester.  An open field is not subject to
the special constitutional protection that extends to "persons,
houses, papers, and effects" because it is not an area in which a
person ordinarily conducts private activities or can reasonably expect
that activities will remain private.  The posting of a field or
placing a gate across an access road does not alter that fundamental
fact and hence does not magically transform a field into an area
protected by the Fourth Amendment.

   Turning first to posting, it is uncontested that the officers here
walked past a "No Trespassing" sign posted on the gate outside
petitioner's field (see J.A. 41), but that fact alone surely did not
create a legitimate expectation of privacy in the field.  The effect
of posting a field is simply to put an individual on notice that he is
about to trespass onto private property and to dispel any notion that
his entry is welcome.  Clearly, a police officer who enters onto
posted property has not simply committed an unintentional trespass.
But it is evident from Hester itself that the open fields doctrine
does not apply only to unintentional trespasses.  While the opinion in
Hester does not specify whether the property was fenced or posted, the
revenue officers there secreted themselves at a distance of 50-100
yards from the house, which they could hardly have imagined to be
public property.  Indeed, one of the revenue officers himself
testified that he supposed the officers were trespassing on Hester's
property.  265 U.S. at 58.  Thus, the Court found no Fourth Amendment
violation in Hester even though the officers were aware that they were
trespassing.  Hester holds that a knowing trespass onto an open field,
although perhaps violative of state property law, does not violate the
Fourth Amendment because a field is not an area in which there is a
legitimate expectation of privacy;  the posting of "No Trespassing"
signs does not alter that conclusion.

   A posted field remains an "open field" because a landowner's
announcement of his desire that persons not enter an open area does
not equal an expectation that they will not enter there.  To the
contrary, landowners generally realize that their open land is liable
to be crossed by others who have some reason to do so -- for example,
if it is a convenient short cut -- despite the presence of a "No
Trespassing" sign.  See e.g., United States v. Edmonds, 611 F.2d 1386,
1388 (5th Cir. 1980).  Accordingly, a landowner has no reasonable
expectation that objects that he leaves in such a field will not be
observed by a member of the public.

   Moreover, state statutes typically permit access by law enforcement
officers to private property under circumstances in which access to
enclosed structures would not be allowed.  For example, Kentucky law
gives conservation officers and all other law enforcement officers
"the right to go upon any land of any person or persons whether
private or public" for various purposes connected with fish and
wildlife research and the enforcement of fish and game laws.  Ky. Rev.
Stat. Ann. Section 150.090 (Bobbs-Merrill repl. 1980).  See also Ky.
Rev. Stat. Ann. Section 149.090 (Bobbs-Merrill repl. 1980 & 1982 Cum.
Supp.) (forest wardens authorized to trespass in the course of their
duties).  This specific authorization is illustrative of a more
general recognition that in many situations a law enforcement officer
is empowered to enter upon private property in the performance of his
duties where an entry by a private party would constitute a trespass.
See, e.g., United States v. Knight, 451 F.2d 275, 278 (5th Cir. 1971),
cert. denied, 405 U.S. 965 (1972);  United States v. Capps, 435 F.2d
637, 640 & n.4 (9th Cir. 1970).  Thus, a landowner who posts his field
can have no reasonable expectation of complete privacy from law
enforcement officers.

   Apart from the posting of the field, petitioner (Br. 23) and the
dissent (Pet. App. 62) rely on the existence of some fences and the
fact that the road was blocked by a locked gate to buttress their view
that petitioner had a legitimate expectation of privacy in his field.
It is apparent for several reasons, however, that the fences and gate
did not enhance petitioner's reasonable expectation of privacy in his
field.

   At the outset, we note that even the existence of a fence
completely surrounding rural property does not necessarily give rise
to a significant expectation of privacy in a field.  Ordinarily the
purpose of such a fence is to mark a boundary or to keep farm animals
within the property.  As one court has noted, such rural fences "are
designed more to keep livestock under control than to keep people
out." State v. Stanton, 490 P.2d 1274, 1279 (Or. Ct. App. 1971).  See
also United States v. Williams, supra, 581 F.2d at 454;  Giddens v.
State, 156 Ga. App. 258, 259, 274 S.E.2d 595, 597 (1980), cert.
denied, 450 U.S. 1026 (1981).  Rural landowners recognize that hunters
and other members of the public frequently enter private fields (see
State v. Cemper, 209 Neb. 376, 307 N.W.2d 820, 823 (1981);  State v.
Stanton, supra, 490 P.2d at 1279)), and that an ordinary livestock
fence does not present much of an obstacle to entry by a person (see
Giddens v. State, supra, 156 Ga. App. at 259, 274 S.E.2d at 597).  /6/
Accordingly, while he may hope that persons will be discouraged from
trespassing or inadvertently wandering onto his property, a landowner
has little expectation that persons who desire to enter his field will
be deterred by the presence of a boundary or livestock fence
surrounding the entire property any more than they would be by the
erection of a "No Trespassing" sign.  /7/ Significantly, the record in
Hester makes clear that the officers there crossed a fence in order to
reach their vantage point (see Transcript of Record at 16, 19-20,
Hester v. United States, supra (No. 243, 1923 Term)), yet the Court
still characterized their entry as onto an "open field" in which there
was no Fourth Amendment protection.

   Recognizing the inevitable limitations on the degree of privacy
that reasonably can be expected in an open field, the courts of
appeals, both before and after Katz, generally have declined to
suppress evidence seized in an open field, even where the property is
fenced and posted.  For example, in United States ex rel. Saiken v.
Bensinger, 546 F.2d 1292 (7th Cir. 1976), cert. denied, 431 U.S. 930
(1977), the court held that a fenced goosehouse came within the ambit
of the open fields doctrine because the goosehouse was beyond the
curtilage and the fence was for the purpose of containing the geese.
Significantly, the court dismissed out of hand the relevance of a
perimeter fence, finding that most of the 20-acre farm "was clearly
open fields" even though the entire farm was surrounded by a fence.
Id. at 1297.  See also United States v. Long, 674 F.2d 848, 852-853
(11th Cir. 1982);  United States v. Williams, supra;  United States v.
Freie, supra;  McDowell v. United States, 383 F.2d 599 (8th Cir.
1967);  Care v. United States, 231 F.2d 22 (10th Cir.), cert. denied,
351 U.S. 932 (1956);  Janney v. United States, 206 F.2d 601 (4th Cir.
1953);  Stark v. United States, 44 F.2d 946 (8th Cir. 1930);  but see
United States v. Dunn, 674 F.2d 1093, 1100 (5th Cir. 1982), petition
for cert. pending, No. 82-508 (fenced-in barn held within curtilage).
/8/

   By the same token, several state court decisions have recognized
the applicability of the open fields doctrine despite posting or the
existence of a fence.  See Luman v. State, 629 P.2d 1275 (Okla. 1981)
(barbed wire fence);  DeMontmorency v. State, 401 So.2d 858 (Fla.
Dist. Ct. App. 1981) (officers crossed over gate into wooded area);
State v. Cemper, supra (entry through open gate in barbed wire fence);
 Giddens v. State, supra (barbed wire fence);  People v. Lashmett, 71
Ill. App. 3d 429, 389 N.E.2d 888 (1979), cert. denied, 444 U.S. 1081
(1980) (officers climbed over two fences);  Ford v. State, 264 Ark.
141, 142, 569 S.W.2d 105, 106 (1978), cert. denied, 441 U.S. 947
(1979) (posted and fenced field with locked gate);  State v. Wren, 115
Ariz. 257, 564 P.2d 946 (Ct. App. 1977) (barbed wire fence);
Commonwealth v. Janek, 242 Pa. Super. Ct. 340, 363 A.2d 1299 (1976)
(field posted and surrounded by embankments and barbed wire fences);
State v. Stanton, supra ("a couple" of livestock fences);  Casey v.
State, 87 Nev. 413, 488 P.2d 546 (1971) (fenced ranch);  but see State
v. Brady, 406 So.2d 1093 (Fla. 1981), cert. granted, 456 U.S. 988
(1982) (violation of Fourth Amendment found where officers cut chain
lock and rammed through gate);  State v. Byers, 359 So. 2d 84 (La.
1978) (marijuana field held not "open" because posted and road
chained).  These decisions rest simply on the notion that posting a
field or erecting a nonexclusionary perimeter fence does not
sufficiently change the nature of a person's expectation of privacy in
an open field that it is reasonable to attach a constitutionally
protected privacy right to items present or activities carried on in
that field.  /9/

   In any event, it is clear in the circumstances of this case that
the gate and fences around petitioner's farm conferred no expectation
of privacy on him whatsoever.  First, the fields in question were
leased by petitioner to two other individuals, while adjoining fields
were apparently leased to other persons (J.A. 34).  Petitioner himself
testified that he had nothing to do with the leased property for the
period of the lease and considered it as if it were owned by the
lessees (J.A. 34-35).  Plainly, petitioner had no expectation
whatsoever that persons unknown to him would not enter these fields at
the invitation of the lessees and hence no reason to believe that any
activities that he carried on in the fields or objects left there
would remain private from outsiders.  Whatever expectation of privacy
theoretically could have been secured by petitioner by posting and
fencing the fields did not exist here because his leasing of the
fields relinquished his right to select the persons permitted to
enter.

   Moreover, the gate and fences involved here provided no basis for
either petitioner or the lessees to believe that persons would enter
the fields by invitation only.  While the gate did restrict
unauthorized entry by vehicles, it is undisputed that there was no
physical impediment to entry by foot.  The record unequivocally shows
that there was fence on only one side of the gate and that the officer
followed a frequently used path around the end where there was no
fence (J.A. 16, 22).  Thus, the "fencing" of petitioner's fields
simply provided notice that it was private property but gave him no
additional reason to expect that persons would not enter the fields on
foot.  Accordingly, any expectation that petitioner or the lessees of
the fields could have had that objects in the fields would remain
private from outsiders entering on foot rested solely on the notice
provided by the "No Trespassing" signs.  /10/ That is simply an
insufficient basis for treating an open field as a private area for
Fourth Amendment purposes -- let alone an area of such privacy that
police are barred from entering unless they have a warrant based on
probable cause.

   The courts of appeals consistently have held that measures that
serve only to notify an outsider of property rights but pose no actual
barrier to entry, such as posting signs, are insufficient to convert
an open field into an area protected by the Fourth Amendment.  See,
e.g., United States v. Hensel, 699 F.2d 18, 32 (1st Cir. 1983);
United States v. Ventling, 678 F.2d 63, 66 (8th Cir. 1982);  United
States v. Williams, supra;  McDowell v. United States, supra.  The
cases cited by petitioner and their supporting amici rejecting
application of the open fields doctrine (see Pet. Br. 28-38;  ACLU Br.
43 n.8) all involved fencing more substantial than that here, which
posed at least some impediment to entry;  none of those cases
recognizes a ligitimate expectation of privacy based solely on the
hope that all outsiders will abide by a "No Trespassing" sign.  /11/
Indeed, even some cases that have refused to find the open fields
doctrine applicable on their particular facts have suggested that mere
posting would be insufficient to confer the protections of the Fourth
Amendment on an open field.  See, e.g., United States v. Van Dyke, 643
F.2d 992, 994 (4th Cir. 1981).  Thus, it is clear that the measures
taken by petitioner did not convert his open field into an area in
which he had a legitimate expectation of privacy so as to render
unconstitutional the officers' warrantless entry onto the field.  See
Note, How Open are Open Fields?  United States v. Oliver, 14 U. Tol.
L. Rev. 133, 159-162 (1982).

 2. Petitioner's Ownership of His Open Field Did Not Create a
Presumption of a Legitimate Expectation of Privacy

   Perhaps recognizing that the erection of a sign does little to
alter the character of an open field and thereby make it an area
infused with such a privacy interest that probable cause and a warrant
is a precondition to entry, amici curiae supporting petitioner take a
somewhat different -- and more sweeping -- approach (see ACLU Br.
24-30).  /12/ Amici contend (ACLU Br. 29) that "(t)he right of a
property owner to exclude others creates a presumptively legitimate
expectation of privacy." In other words, despite the lesson of Katz
that Fourth Amendment rights do not depend on property rights (see
page 14, supra), amici contend that mere ownership of property
automatically convers the full panoply of Fourth Amendment protections
upon the owner in every portion of the property, even an open field.
Amici continue by explaining (ACLU Br. 29) that "(t)his presumption
(of a legitimate expectation of privacy) may properly be defeated only
when the property owner has failed to exercise her right to exclude."
Amici explain Hester on this basis.  Since Hester "had not exhibited
any intention to keep * * * strangers from his father's land," amici
claim (ACLU Br. 12), he "forfeited his constitutional protection
against unwanted police intrusion" (emphasis added).  This approach
cannot withstand analysis.

   Amici's explanation of the open fields doctrine turns the Fourth
Amendment on its head.  First, of course, it is simply not correct
that a mere ownership interest in property in and of itself creates a
legitimate expectation of privacy.  While it is true that a property
owner's right to exclude others (see ACLU Br. 29) gives him the right
to take measures that may create an expectation of privacy, that does
not mean that a privacy interest is inherent in the mere fact of
ownership of the property.  Katz itself refutes such a suggestion, and
the only authority relied upon by amici for this novel proposition
clearly states that "even a property interest in premises may not be
sufficient to establish a legitimate expectation of privacy." Rakas v.
Illinois, supra, 439 U.S. at 144 n.12 (citing, inter alia, Hester).
An individual's legitimate expectation of privacy in an area derives
from the reasonableness of his expectation that outsiders will not
enter there;  there is no basis for such an expectation in an open
field.

   Second, and more importantly, amici's attempt to harmonize Hester
with their property-based theory of expectation of privacy is
fundamentally flawed.  Indeed, amici's own brief exposes the fallacy
of their argument.  Amici argue that Hester did at one time have a
legitimate expectation of privacy in his open field, but that he
forfeited that expectation and its concomitant Fourth Amendment
protection because he failed to take any measures to keep strangers
off the land (ACLU Br. 12).  However, the Fourth Amendment does not
require an individual to take affirmative measures to retain
constitutional protections that he already has.  To quote amici,
"(t)he Constitution protects a person's reasonable expectation of
privacy;  it does not require one to secure it by force" (ACLU Br.
33).  Thus, if an individual has a legitimate expectation of privacy
in a place, such as his home, he does not forfeit his constitutional
protection against unwanted entry if he fails to take a particular
action to secure the place, for example, locking the door (cf. ACLU
Br. 36).  The protections of the Fourth Amendment are not forfeited by
inaction;  that would "shift to the citizen the onus" (ACLU Br. 33-34)
of protecting what the Constitution already protects.  /13/

   Thus, amici's contention that Hester forfeited his constitutional
protection against unwanted entry onto his property because he failed
to take measures to keep outsiders away is untenable.  The defect in
amici's analysis lies in its faulty premise;  Hester never had a
legitimate expectation of privacy in his open field.  Rather, the
correct explanation of the holding in Hester is the one given by the
Court there (265 U.S. at 59):  "(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." Because Hester had
no expectation of privacy in his field and took no exclusionary
measures that created one, the officers' entry onto his property did
not violate the Fourth Amendment.  By the same token, petitioner's
posting of "No Trespassing" signs was not a measure that created a
reasonable expectation of privacy in his field, and hence the
officers' entry was constitutional.  /14/

 C. Even Assuming Privately Owned Woods Or Fields Are In Some
Circumstances Entitled To Fourth Amendment Protection, A Warrantless
Search On The Basis Of Reasonable Suspicion Of Criminal Activity Is
Permitted

   The fact that an open field is not an area in which a landowner has
a legitimate expectation of privacy does not necessarily mean that the
character of the land cannot be altered so as to convert the field or
a portion of it into an area subject to Fourth Amendment protections.
By virtue of his ownership, a landowner has a right to develop his
land and make improvements that may give him a legitimate expectation
of privacy.  Obviously, houses and other buildings stand on what once
was an open field, yet they are fully subject to the protections of
the Fourth Amendment.  Petitioner and the dissent below essentially
argue that the mere notification of a desire to exclude outsiders by
the erection of a "No Trespassing" sign sufficiently alters the
character of an open field to confer a legitimate expectation of
privacy upon an individual's activities there.  In our view, as argued
above (pages 17-18, supra), posting a field is too insubstantial a
measure to be reasonably expected, as a practical matter, to exclude
outsiders from a field, and hence it cannot create a legitimate
expectation of privacy in an open field.  By contrast, when a
landowner takes measures to prevent entry by the public, such as
construction of an exclusionary fence, as opposed to the insubstantial
livestock fence that usually surrounds a field, it is at least
arguable that he has a limited expectation of privacy in the enclosed
area.  See, e.g., United States v. FMC Corp., 428 F. Supp. 615
(W.D.N.Y. 1977), aff'd, 572 F.2d 902 (2d Cir. 1978) (eight-foot high
fence topped with barbed wire).

   This is not to concede that even substantial measures taken to
exclude outsiders from entering an open field should implicate the
protections of the Fourth Amendment.  Although surrounded by an
exclusionary fence, a field is still a field -- and unmistakably does
not become a person, house, paper, or effect.  But even assuming that
exclusionary measures at some point create a constitutionally
protected privacy interest in a field that requires a reasonable
justification for an official intrusion, it does not follow that the
field should be given the same constitutional protection as a home, an
office, or even an automobile.  That is, a search of such a field can
be reasonable within the meaning of the Fourth Amendment even if not
conducted pursuant to a warrant or based on probable cause.  Because
the privacy interest in a field, even if measures have been taken to
exclude outsiders, does not approach the privacy interest in a home,
an office, luggage or other containers of personal effects, or a car,
a search of that field is a significantly lesser intrusion than a
search of traditionally more private areas and correspondingly
requires a lesser degree of justification.

   Accordingly, if the traditional understanding of the open fields
doctrine is to be modified by extending the protections of the Fourth
Amendment to an open field where some measures have been taken to
prevent entry by outsiders (or, a fortiori, if petitioner's contention
is accepted that insubstantial exclusionary measures such as posting a
"No Trespassing" sign implicate Fourth Amendment protections), we
submit that an entry by law enforcement officers onto such a field
does not violate the Fourth Amendment if the entry is justified by a
reasonable suspicion of criminal activity.

   The substantive command of the Fourth Amendment prohibits
"unreasonable searches and seizures." In determining whether this "key
principle" of reasonableness has been satisfied, the courts must
engage in a "balancing of competing interests." Michigan v. Summers,
452 U.S. 692, 700 n.12 (1981), quoting Dunaway v. New York, 442 U.S.
200, 219 (1979) (White, J., concurring).  Specifically, the
reasonableness of a search or seizure is judged "by balancing its
intrusion on the individual's Fourth Amendment interests against its
promotion of legitimate governmental interests." Delaware v. Prouse,
440 U.S. 648, 654 (1979) (footnote omitted).  See also Brown v. Texas,
443 U.S. 47, 50-51 (1979);  United States v. Martinez-Fuerte, 428 U.S.
543, 555 (1976);  Camara v. Municipal Court, 387 U.S. 523, 536-537
(1967).  We submit that the privacy intrusion involved in a search of
a field is so limited that, weighed against the government interest in
ferreting out suspected criminal activity, such a search is
"reasonable" if based on a reasonable suspicion of criminal activity.
/15/

   First, even a field surrounded by an exclusionary fence is subject
to observation from the air and thus cannot be regarded as wholly
private.  /16/ Contrary to amici's contention (ACLU Br. 37 n.7),
aerial observation by law enforcement agents has consistently been
held not to invade an expectation of privacy recognized under the
Fourth Amendment.  /17/ Indeed, even the dissent below recognized
(Pet. App. 63-64) that the marijuana fields here could lawfully have
been observed by the police from the air.  See also Amici Curiae Brief
of California Farm Bureau Federation and Florida Farm Bureau
Federation in Support of Petitioner at 16.  Because the manner of
observation is ordinarily of no consequence to the landowner, he has a
limited legitimate expectation of preserving the privacy of things
freely observable from the air.  See Pet. App. 36 n.4;  see also
United States v. Knotts, supra, slip op. 9.

   More important, the intrusion on the landowner's privacy when
police enter a field is not even remotely comparable to the intrusion
that is involved when police enter a home or business premises or
search through private papers.  In the case of a search of a private
residence or office, if the police are mistaken in their suspicion of
criminal activity, they necessarily disrupt an area that people
reserve for their most personal and private matters.  The exposure of
these matters to outsiders is a most severe intrusion into the privacy
of the innocent individual.  In order to safeguard these important
privacy interests against unjustified invasion, the Fourth Amendment
interposes two requirements before a home or office can be searched:
the substantive requirement that the police have probable cause to
believe that evidence of criminal activity will be found and the
procedural requirement that this determination be made by a neutral
and detached magistrate.

   If the police err in invading an open field, however, the
consequences are much less severe.  The entry is a minimal disruption
of an individual's privacy.  Exposure to the police of the contents of
an open field is relatively unintrusive.  In most cases, the
consequence is simply that the police observe nothing but a field and
perhaps some cornstalks or cows;  an individual is highly unlikely to
keep exposed in an open field personal effects that he wishes to keep
private.  Because the invasion of privacy resulting from an erroneous
search is substantially smaller in the case of a field than in the
case of a residence, an office, a closed container, or even an
automobile, it is reasonable that the Fourth Amendment standard that
must be satisfied before a search may occur be less severe.

   Suppose, for instance, that the police receive an anonymous tip
that a kidnap victim is being held in the woods inside posted and
fenced private property or that a cache of automatic weapons is hidden
in a wheat field on a large, fenced farm.  Or suppose that an EPA
inspector receives information that hazardous chemicals are being
illegally dumped near a stream running through such property.  Such
tips afford reasonable suspicion of unlawful activity but are
insufficiently susstantiated to provide probable cause, without which
no warrant can be obtained.  While the police could not rely on
information of this quality to search a house, reason dictates that
the information affords a sufficient basis to undertake a search
implicating the comparatively inconsequential privacy interests in a
field or woods.  Accordingly, a rational balancing of societal and
individual interests in such circumstances calls for allowing a search
upon a justification that, while concrete and objectively verifiable,
is less substantial than is needed to justify official inspection of
more private areas.

   This Court has recognized in other contexts that the two basic
constitutional prerequisites to a search of a residence do not
necessarily apply where there is a substantially reduced privacy
intrusion.  For example, a search of an automobile is a significantly
lesser intrusion than a search of a residence.  As the Court explained
in United States v. Chadwick, 433 U.S. 1, 12 (1977), quoting Cardwell
v. Lewis, 417 U.S. 583, 590 (1974) (plurality opinion):

      One has a lesser expectation of privacy in a motor vehicle
      because its function is transportation and it seldom serves as
      one's residence or as the repository of personal effects * * * .
       It travels public thoroughfares where both its occupants and
      its contents are in plain view.

   As a result, the warrant requirement is thought to be unnecessary
to protect adequately the owner's privacy interests in the vehicle's
interior.  See also United States v. Knotts, supra, slip op. 5;
Arkansas v. Sanders, 442 U.S. 753, 761 (1979);  Rakas v. Illinois,
supra, 439 U.S. at 153-155 (Powell, J., concurring);  South Dakota v.
Opperman, 428 U.S. 364, 368 (1976).  Even so, it is clear that the
likelihood that personal effects will be found in a car (perhaps while
in transit to or from a residence) /18/ is substantially greater than
the likelihood that such personal effects will be found in an open
field.

   Similarly, seizures that are a minimal intrusion compared to an
arrest may be effected on less than probable cause.  See, e.g., United
States v. Cortez, 449 U.S. 411 (1981);  United States v.
Brignoni-Ponce, 422 U.S. 873 (1975);  Terry v. Ohio, 392 U.S. 1
(1968).  And in the context of administrative searches, where there is
generally a reduced expectation of privacy (see Donovan v. Dewey, 452
U.S. 594, 598-599 (1981), a search satisfies the "reasonableness"
requirement of the Fourth Amendment despite absence of probable cause
to believe that a violation will be found, even where a residence is
involved.  See Donovan v. Dewey, supra, 452 U.S. at 598-602;  Marshall
v. Barlow's, Inc., 436 U.S. 307, 320-321 (1978);  United States v.
Biswell, 406 U.S. 311, 316 (1972);  Camara v. Municipal Court, supra,
387 U.S. at 538.

   Given the extremely limited nature of the privacy intrusion
involved in the search of a field, it is appropriate that such
searches not be constrained by the strictest level of Fourth Amendment
protection.  There will be situations where the police receive
information not amounting to probable cause that there is evidence of
criminal activity in a field, such as a marijuana crop, but it would
be difficult to investigate this suspicion further without entry onto
the field.  /19/ In light of the minimal adverse consequences that
would occur from an entry if the information turns out to be
erroneous, it is "reasonable" within the meaning of the Fourth
Amendment, even if a field is posted or surrounded by an exclusionary
fence, to permit police to enter onto it on the basis of reasonable
suspicion of criminal activity, rather than being forced to ignore the
information they have received.  See United States v. Johnson, 561
F.2d 832, 852-853 (D.C. Cir.) (MacKinnon, J., concurring), cert.
denied, 432 U.S. 907 (1977);  United States v. Knight, supra, 451 F.2d
at 278.  /20/

   There can be little doubt that the police officers had a reasonable
suspicion that criminal activity was afoot on petitioner's farm before
they entered.  They received an anonymous tip stating that petitioner
had a large amount of marijuana growing on his farm and giving
specific directions on how to find the marijuana, namely, by following
the Sugar Camp Road (J.A. 2-3, 19).  This tip was supplemented by
other reports the officers had received from people in the community
that there was questionable activity on petitioner's farm (J.A. 3).
This information raised a sufficient degree of suspicion that the
officers would have been remiss in their duties had they not
investigated further, and it surely justified the minimal privacy
intrusion involved in walking along the path through petitioner's farm
to the open field where the marijuana was growing.  /21/ Thus, even if
the Court rejects our primary submission that the posting of his field
and the presence of a gate across the road did not give petitioner a
legitimate expectation of privacy in his field that implicates Fourth
Amendment protections, the police entry onto the field did not violate
the Fourth Amendment's proscription against "unreasonable searches and
seizures" because it was based on a reasonable suspicion of criminal
activity.

                              CONCLUSION

   The judgment of the court of appeals should be affirmed.

   Respectfully submitted.

   REX E. LEE

      Solicitor General

   D. LOWELL JENSEN

      Assistant Attorney General

   ANDREW L. FREY

      Deputy Solicitor General

   ALAN I. HOROWITZ

      Assistant to the Solicitor General

   MAY 1983

   /1/ The testimony at the suppression hearing indicated that a row
of trees obscured the view of the field from a barn on petitioner's
property (J.A. 30-31).  The detective testified that the field where
the marijuana was found was visible from the gate, but that it was not
possible to determine from that distance that it was marijuana growing
in the field (J.A. 16).

   /2/ The curtilage is an area surrounding the house that is
habitually used for family purposes and hence is of heightened privacy
interest.  See Black's Law Dictionary 346 (5th ed. 1979).  In the
urban setting, for example, a fenced yard appurtenant to the house
excluding outsiders would generally be considered curtilage.  See,
e.g., United States v. Martino, 664 F.2d 860, 879 (2d Cir. 1981)
(Oakes, J., concurring);  Hobson v. United States, 226 F.2d 890, 894
(8th Cir. 1955).  The common law recognized that the curtilage was to
be treated as a part of the house for some purposes (see 4 W.
Blackstone, Commentaries, ch. 16, at 225 (Univ. of Chicago Press ed.
1979)), and the Court in Hester cited to this common law rule.  265
U.S. at 59.  Accordingly, it has been recognized that the open fields
doctrine does not permit warrantless searches of the curtilage, where
the homeowner is considered to have a legitimate expectation of
privacy.  See, e.g., United States v. Van Dyke, 643 F.2d 992, 993 (4th
Cir. 1981);  United States v. Williams, 581 F.2d 451, 453 (5th Cir.
1978), cert. denied, 440 U.S. 972 (1979);  Care v. United States, 231
F.2d 22, 25 (10th Cir.), cert. denied, 351 U.S. 932 (1956).

   /3/ The Court in Katz noted that the issue involved there, because
of significant scientific advances in the area of electronic
surveillance and "the vital role that the public telephone has come to
play in private communication," was one that could not specifically
have been contemplated by the Framers or even by the Court in earlier
years.  See 389 U.S. at 352;  id. at 362 (Harlan, J., concurring).  As
the court below noted (Pet. App. 34-35), no comparable technological
advance provides any basis for affording a greater degree of Fourth
Amendment protection to a field today than at the time Hester was
decided or when the Fourth Amendment protection of "persons, houses,
papers, and effects" was first enacted.

   /4/ To buttress his contention that Katz discredited Hester,
petitioner adopts (Br. 15-19) the dissent's premise (see Pet. App.
44-47) that the open fields doctrine is actually based on this Court's
decision in Olmstead v. United States, 277 U.S. 438 (1928), which was
expressly overruled by Katz.  This premise is false.  The unremarkable
declaration of the Court in Hester that the special protection of the
Fourth Amendment "is not extended to the open fields" (265 U.S. at 59)
did not rest on the subsequent establishment of a much more general,
and controversial, rule in Olmstead holding that the Fourth Amendment
protects only against physical invasions of certain areas.  That is
quite clear from the decisions themselves.  Hester was a unanimous
decision;  Olmstead, decided only four years later, was a 5-4 decision
so controversial that it prompted each of the dissenters to write
separately.  Three of the dissenters had joined the Court's decision
in Hester, including Justice Holmes, its author, and none saw any
reason to repudiate their previous decision in the course of their
dissents in Olmstead.  Hence, Katz's overruling of Olmstead -- in the
same wiretapping context in which Olmstead was handed down -- casts no
doubt on the validity of the distinct, and independent, open fields
doctrine of Hester.

   /5/ The conclusion of Hester that the Fourth Amendment is not
violated when police trespass onto an open field does not suggest that
a landowner is powerless to prevent such a trespass.  As a practical
matter, law enforcement officers likely will enter onto private
property only if they have good reason to suspect that criminal
activity is afoot.  If, however, a landowner is being harassed by
unjustified police entry onto his property, he can seek damages or an
injunction prohibiting the police from further trespass, in accordance
with remedies supplied by state law.

   /6/ Indeed, in at least two of the reported cases concerning the
applicability of the open fields doctrine to a fenced field, law
enforcement officers entered the field after the criminal activity was
reported to them by members of the public who had trespassed on the
property.  See State v. Stanton, supra (two teenagers);  State v.
Byers, 359 So.2d 84 (La. 1978) (hunter).

   /7/ A fence, depending on its nature, may designate a particular
area of a farm as more private, and a fence closely surrounding a
residence may be an important factor in defining the curtilage.  See,
e.g., United States v. Van Dyke, supra, 643 F.2d at 994;  United
States v. Williams, supra, 581 F.2d at 454.  But a boundary fence that
surrounds a large farm does not convert all the open areas on the farm
into areas protected by the Fourth Amendment.

   /8/ Numerous other decisions, not involving fields described as
fenced or posted, also recognize the continuing vitality of the Hester
open fields doctrine after Katz.  See, e.g., Patterson v. National
Transportation Safety Board, 638 F.2d 144 (10th Cir. 1980);  United
States v. Ramapuram, 632 F.2d 1149, 1155 (4th Cir. 1980), cert.
denied, 450 U.S. 1030 (1981);  United States v. Basile, 569 F.2d 1053
(9th Cir. 1978);  Patler v. Slayton, supra;  United States v. Brown,
487 F.2d 208, 210 (4th Cir. 1973), cert. denied, 416 U.S. 909 (1974).

   /9/ Of course, there are areas outside the home that are
sufficiently private to warrant Fourth Amendment protection.  Thus,
the courts have invalidated searches of enclosed structures (see,
e.g., United States v. Holmes, 521 F.2d 859 (5th Cir. 1975);  Adair v.
State, 298 So. 2d 671, 674 (Ala. Crim. App. 1974)) or open areas found
to be part of the curtilage (see, e.g., United States v. Van Dyke,
supra;  Wattenburg v. United States, 388 F.2d 853, 857-858 (9th Cir.
1968)).

   It should be noted that, contrary to petitioner's (Br. 15-20) and
amici curiae's (see note 12, infra) (ACLU Br. 18-23) suggestion,
consideration of the traditional concept of curtilage has not become
invalid after Katz simply because the concept was used in Olmstead.
Kats, of course, did not completely eliminate for Fourth Amendment
purposes the relevance of location.  Obviously, the protections of the
Fourth Amendment are stronger in the home than in other areas of
reduced privacy interest.  See, e.g., Payton v. New York, 445 U.S. 573
(1980).  The curtilage is an area traditionally associated with the
home (see note 2, supra) and hence entitled to greater protection than
a field.  Moreover, the concept of curtilage does not embody a "rigid
property concept()" (Pet. Br. 17) or "per se 'locational' theory"
(Pet. Br. 18);  to the contrary, even before Katz, the concept of
curtilage in this connection was based on consideration of a multitude
of factors that basically were directed at determining whether an area
was entitled to some expectation of privacy because of its association
with the home.  See, e.g., United States v. Arboleda, 633 F.2d 985,
992 (2d Cir. 1980), cert. denied, 450 U.S. 917 (1981);  Care v. United
States, supra, 231 F.2d at 25.

   /10/ Petitioner also suggests (Br. 23) that the "highly secluded"
nature of the marijuana fields contributed to his legitimate
expectation of privacy.  It is true, of course, that the fields were
partly secluded in the sense that trees obstructed a view of the
fields from a point off petitioner's property in one direction and the
marijuana was not discernible at all from off petitioner's property.
But that is not dispositive of the question presented here concerning
the application of the open fields doctrine, which involves the
admissibility of evidence discovered as a result of a technical
trespass onto private property.  The fields involved here plainly were
not secluded from persons who entered petitioner's property on the
unobstructed path.  Contrary to petitioner's implication (Br. 13) that
the officers hacked their way through dense underbrush to reach the
marijuana, the record shows that the investigating officers simply
walked along the road or path until they discovered the marijuana
(J.A. 4-5, 19.) Thus, the fields where the marijuana was discovered
were just as "open" for the purposes of the open fields doctrine as
any other area of petitioner's property beyond the "No Trespassing"
sign.  To the extent it may be argued that some portion of an open
field may enjoy additional Fourth Amendment protection because the
topography of the land secludes it from the rest of the field, that
question is not presented here.

   Petitioner also notes (Br. 23) that the officers were mistaken for
hunters and told that no hunting was allowed in the field.  This also
put the officers on notice that they were on private property, but,
given that such notice had already been given by the "No Trespassing"
signs, it is of no particular relevance to the question presented.  It
should be noted, however, that petitioner's assertion (Br. 5-6) that
the officers ignored this warning is contradicted by the record.  To
the contrary, the officers shouted back that they were not hunters,
but police officers, and backtracked to try to speak to the person who
had called to them.  When they found no one, they proceeded on their
way down the road and discovered the marijuana.  See J.A. 304.

   /11/ In the case consolidated with this one, State v. Thornton, 453
A.2d 489 (Me. 1982), cert. granted, No. 82-1273 (Apr. 4, 1983), the
court rejected application of the open fields doctrine because of the
presence of "No Trespassing" signs and a dilapidated stone wall.
While that decision supports petitioner's contention, we regard it as
erroneous and urge this Court to reverse it for the same reasons that
support affirmance in this case.

   /12/ We refer here to the brief as amici curiae filed on behalf of
the American Civil Liberties Union of Northern California, the Mexican
American Legal Defense and Educational Fund, and California Rural
Legal Assistance, which for convenience will be referred to as "ACLU
Br."

   /13/ Of course, an individual may forfeit his legitimate
expectation of privacy and concomitant Fourth Amendment protection in
an area by taking some affirmative action.  For example, the owner of
a home surely forfeits his legitimate expectation of privacy in a
house or apartment if he rents it to another individual.  Similarly,
an individual may lose his privacy interest in an article if he
abandons it or exposes it to plain view.  Hester however, did none of
these things.  None of the incriminating evidence found by the police
in Hester was exposed to anyone who was not trespassing.  Cf. ACLU Br.
11-12.

   /14/ Amici apparently also suggest (see ACLU Br. 21-23, 27-29,
45-48) that petitioner's field was entitled to special Fourth
Amendment protection because it was a form of "commercial premises."
This is entirely untenable.  The text of the Fourth Amendment actually
focuses on private premises ("houses"), not commercial premises.  It
is true, of course, that commercial premises, such as offices,
factories, and warehouses, may be protected by the Fourth Amendment if
they are possessed of attributes that confer a legitimate expectation
of privacy on an individual -- whether or not he is engaged in a
commercial enterprise.  If anything, however, the protections of the
Fourth Amendment apply less stringently to a commercial enterprise
than to personal effects.  See Donovan v. Dewey, 452 U.S. 594, 598-599
(1981);  United States v. Kaiyo Maru No. 53, 699 F.2d 989, 995 (9th
Cir. 1983).  At any rate, an open field used for commercial purposes
is no more private than an open field limited to personal use.  In
particular, amici's contention (ACLU Br. 23 n.5) that petitioner's
field was entitled to special constitutional protection because it was
used for the illegal commercial purpose of growing marijuana is
preposterous.

   /15/ Where a search invades a substantial privacy interest, it
generally is considered reasonable only if conducted in accordance
with the Warrant Clause of the Fourth Amendment.  See United States v.
Chadwick, 433 U.S. 1, 11 (1977).  If, however, a law enforcement
action is permitted on the basis of suspicion short of probable cause,
then no warrant can be required.

   /16/ Apart from aerial observation by law enforcement agents, open
areas of private property are subject to intentional observation from
the air by aircraft owned by private parties, such as traffic
helicopters and news media seeking aerial photographs, or inadvertent
observation by persons in aircraft flying over the property on their
way to another destination.  See, e.g., United States v. DeBacker, 493
F. Supp. 1078, 1081 (W.D. Mich. 1980).

   /17/ See, e.g., United States v. Allen, 675 F.2d 1373, 1380-1381
(9th Cir. 1980), cert. denied, 454 U.S. 833 (1981);  United States v.
Mullinex, 508 F. Supp. 512, 514-515 (E.D. Ky. 1980);  United States v.
DeBacker, supra, 493 F. Supp. at 1081;  Murphy v. State, 413 So. 2d
1268 (Fla. Dist. Ct. App. 1982);  Goehring v. State, 627 S.W.2d 159
(Tex. Crim. App. 1982);  State v. Layne, 623 S.W.2d 629 (Tenn. Crim.
App. 1981);  People v. Lashmett, supra, 71 Ill. App. 3d at 531, 389
N.E.2d at 890;  State v. Stachler, 58 Hawaii 412, 418-419, 570 P.2d
1323, 1327-1328 (1977);  Dean v. Superior Court, 35 Cal. App. 3d 112,
117-118, 110 Cal. Rptr. 585, 589-590 (1973);  cf. People v. Sneed, 32
Cal. App. 3d 535, 542-543, 108 Cal. Rptr. 146, 150-151 (1973)
(helicopter hovering below navigable airspace at height of 20-25 feet
held unlawful).

   In Dow Chemical Co. v. United States, 536 F. Supp. 1355 (E.D. Mich.
1982), relied upon by both petitioner (Br. 35-36) and amici (ACLU Br.
38-39 n.7), the court held that the use of aerial photographs
contracted for by the Environmental Protection Agency and taken by a
private company violated the Fourth Amendment because enlargement of
the photographs revealed details of the outside of Dow's Midland,
Michigan, plant not visible to the naked eye (the enlargements
referred to in the opinion were made by Dow Chemical for purposes of
litigation, not by the government).  That case is consistent with the
long line of decisions cited above recognizing the constitutionality
of aerial observation.  The decision is plainly based on the invasion
of privacy that the court found present in the use of the photographic
equipment and the possibility of enlargement to show detail, and it
suggests that an overflight limited to naked eye observation would not
violate the Fourth Amendment.  See, e.g., 536 F. Supp. at 1367, 1372.
In any event, we view the Dow Chemical decision as erroneous, and it
has been appealed to the Sixth Circuit, No. 82-1811.

   /18/ Even if the personal effects are stored in the automobile in a
container that indicates that it contains personal effects, they may
be exposed by a warrantless search.  See United States v. Ross, 456
U.S. 798 (1982).

   /19/ Even where an aircraft or helicopter could verify the
suspected presence of a marijuana crop as accurately as an officer on
foot, the incremental likelihood that the officer will see private
matter not visible from the air is so slight that we find it hard to
believe that the Fourth Amendment requires the great added expense of
aerial surveillance to safeguard individual privacy interests.

   /20/ Several courts have suggested that certain police
investigative techniques that are more in the nature of searches than
seizures implicate the protections of the Fourth Amendment, yet may be
conducted based on a level of suspicion less than probable cause.  See
United States v. Allen, supra, 675 F.2d at 1381 (helicopter
surveillance);  United States v. Beale, 674 F.2d 1327, 1334-1335 (9th
Cir. 1982), petition for cert. pending, No. 82-674 (dog sniff);
United States v. Michael, 645 F.2d 252, 258 (5th Cir.) (en banc),
cert. denied, 454 U.S. 950 (1981) (beeper installation and
monitoring);  United States v. Curtis, 562 F.2d 1153, 1156 (9th Cir.
1977), cert. denied, 439 U.S. 910 (1978) (beeper installation and
monitoring);  United States v. Johnson, 413 F.2d 1396, 1399-1400 (5th
Cir. 1969), aff'd en banc, 431 F.2d 441 (1970) (inspection of
automobile vehicle identification number).  The Court has since held
in United States v. Knotts, supra, that monitoring a beeper does not
implicate any protected Fourth Amendment interest.  By the same token,
we do not necessarily agree that the other investigative techniques
listed above implicate any constitutional protection.  Nevertheless,
we believe that the courts in these decisions have utilized a sound
analytic framework in acknowledging that certain classes of searches,
although subject to the Fourth Amendment, are reasonably justified
when the police possess reasonable suspicion of criminal activity
short of probable cause, but would be unreasonable if conducted on a
random or suspicionless basis.

   /21/ We emphasize again that, had the suspicions entertained by the
police been unfounded, their activities would have produced a quiet
afternoon stroll through the cornfields, but no likely exposure to any
of petitioner's private effects.