CERTIORARI TO COURT OF APPEALS OF CALIFORNIA, FIRST APPELLATE DISTRICT.
Burger, C. J., delivered the opinion of the Court, in which White, Rehnquist, Stevens, and O'connor, JJ., joined. Powell, J., filed a dissenting opinion, in which Brennan, Marshall, and Blackmun, JJ., joined, post, p. 215.
CHIEF JUSTICE BURGER delivered the opinion of the Court.
We granted certiorari to determine whether the Fourth Amendment is violated by aerial observation without a warrant from an altitude of 1,000 feet of a fenced-in backyard within the curtilage of a home.
On September 2, 1982, Santa Clara Police received an anonymous telephone tip that marijuana was growing in respondent's backyard. Police were unable to observe the contents of respondent's yard from ground level because of a 6-foot outer fence and a 10-foot inner fence completely enclosing the yard. Later that day, Officer Shutz, who was assigned to investigate, secured a private plane and flew over respondent's house at an altitude of 1,000 feet, within navigable airspace; he was accompanied by Officer Rodriguez. Both officers were trained in marijuana identification. From the overflight, the officers readily identified marijuana plants 8 feet to 10 feet in height growing in a 15- by 25-foot plot in respondent's yard; they photographed the area with a standard 35mm camera.
On September 8, 1982, Officer Shutz obtained a search warrant on the basis of an affidavit describing the anonymous tip and their observations; a photograph depicting respondent's house, the backyard, and neighboring homes was attached to the affidavit as an exhibit. The warrant was
executed the next day and 73 plants were seized; it is not disputed that these were marijuana.
After the trial court denied respondent's motion to suppress the evidence of the search, respondent pleaded guilty to a charge of cultivation of marijuana. The California Court of Appeal reversed, however, on the ground that the warrantless aerial observation of respondent's yard which led to the issuance of the warrant violated the Fourth Amendment. 161 Cal. App. 3d 1081, 208 Cal. Rptr. 93 (1984). That court held first that respondent's backyard marijuana garden was within the "curtilage" of his home, under Oliver v. United States, 466 U.S. 170 (1984). The court emphasized that the height and existence of the two fences constituted "objective criteria from which we may conclude he manifested a reasonable expectation of privacy by any standard." 161 Cal. App. 3d, at 1089, 208 Cal. Rptr., at 97.
Examining the particular method of surveillance undertaken, the court then found it "significant" that the flyover "was not the result of a routine patrol conducted for any other legitimate law enforcement or public safety objective, but was undertaken for the specific purpose of observing this particular enclosure within [respondent's] curtilage." Ibid. It held this focused observation was "a direct and unauthorized intrusion into the sanctity of the home" which violated respondent's reasonable expectation of privacy. Id., at 1089-1090, 208 Cal. Rptr., at 98 (footnote omitted). The California Supreme Court denied the State's petition for review.
We granted the State's petition for certiorari, 471 U.S. 1134 (1985). We reverse.
The State argues that respondent has "knowingly exposed" his backyard to aerial observation, because all that was seen was visible to the naked eye from any aircraft flying overhead. The State analogizes its mode of observation to a knothole or opening in a fence: if there is an opening, the police may look.
The California Court of Appeal, as we noted earlier, accepted the analysis that unlike the casual observation of a private person flying overhead, this flight was focused specifically on a small suburban yard, and was not the result of any routine patrol overflight. Respondent contends he has done all that can reasonably be expected to tell the world he wishes to maintain the privacy of his garden within the curtilage without covering his yard. Such covering, he argues, would defeat its purpose as an outside living area; he asserts he has not "knowingly" exposed himself to aerial views.
The touchstone of Fourth Amendment analysis is whether a person has a "constitutionally protected reasonable expectation of privacy." Katz v. United States, 389 U.S. 347, 360 (1967) (Harlan, J., concurring). Katz posits a two-part inquiry: first, has the individual manifested a subjective expectation of privacy in the object of the challenged search? Second, is society willing to recognize that expectation as reasonable? See Smith v. Maryland, 442 U.S. 735, 740 (1979).
Clearly -- and understandably -- respondent has met the test of manifesting his own subjective intent and desire to maintain privacy as to his unlawful agricultural pursuits. However, we need not address that issue, for the State has not challenged the finding of the California Court of Appeal that respondent had such an expectation. It can reasonably be assumed that the 10-foot fence was placed to conceal the marijuana crop from at least street-level views. So far as the normal sidewalk traffic was concerned, this fence served that purpose, because respondent "took normal precautions to maintain his privacy." Rawlings v. Kentucky, 448 U.S. 98, 105 (1980).
Yet a 10-foot fence might not shield these plants from the eyes of a citizen or a policeman perched on the top of a truck or a two-level bus. Whether respondent therefore manifested
a subjective expectation of privacy from all observations of his backyard, or whether instead he manifested merely a hope that no one would observe his unlawful gardening pursuits, is not entirely clear in these circumstances. Respondent appears to challenge the authority of government to observe his activity from any vantage point or place if the viewing is motivated by a law enforcement purpose, and not the result of a casual, accidental observation.
We turn, therefore, to the second inquiry under Katz, i. e., whether that expectation is reasonable. In pursuing this inquiry, we must keep in mind that "[the] test of legitimacy is not whether the individual chooses to conceal assertedly 'private' activity," but instead "whether the government's intrusion infringes upon the personal and societal values protected by the Fourth Amendment." Oliver, supra, at 181-183.
Respondent argues that because his yard was in the curtilage of his home, no governmental aerial observation is permissible under the Fourth Amendment without a warrant.*fn1 The history and genesis of the curtilage doctrine are instructive. "At common law, the curtilage is the area to which extends the intimate activity associated with the 'sanctity of a man's home and the privacies of life.'" Oliver, supra, at ...