Amendment 4 — Katz And Reasonable Expectation Of Privacy Test

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Fourth Amendment :

The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.

Following Olmstead v. United States and Goldman v. United States, the Court determined in May 1967 that “[t]he premise that property interests control the right of the government to search and seize has been discredited” and that “the principal object of the Fourth Amendment is the protection of privacy rather than property.” [1](https://www.law.cornell.edu/constitution-conan/amendment-4/katz-and-reasonable-expectation-of-privacy-test#fn1amd4 " Warden v. Hayden, 387 U.S. 294, 304 (1967). ") Overruling Olmstead and Goldman in December 1967, the Court dispensed with the requirement of actual physical trespass because the Fourth Amendment “protects people, not places” to make electronic surveillance subject to the Amendment’s requirements.[2](https://www.law.cornell.edu/constitution-conan/amendment-4/katz-and-reasonable-expectation-of-privacy-test#fn2amd4 " Katz v. United States, 389 U.S. 347, 353 (1967) (warrantless use of listening and recording device placed on outside of phone booth violates Fourth Amendment). See also Kyllo v. United States, 533 U.S. 27, 32–33 (2001) (holding presumptively unreasonable the warrantless use of a thermal imaging device to detect activity within a home by measuring heat outside the home, and noting that a contrary holding would permit developments in police technology “to erode the privacy guaranteed by the Fourth Amendment.” ")

The test, the Court propounded in Katz v. United States, examined the expectation of privacy upon which one may “justifiably” rely.[3](https://www.law.cornell.edu/constitution-conan/amendment-4/katz-and-reasonable-expectation-of-privacy-test#fn3amd4 " 389 U.S. at 353. Justice John Harlan, concurring, formulated a two pronged test for determining whether the privacy interest is paramount: “first that a person have exhibited an actual (subjective) expectation of privacy and, second, that the expectation be one that society is prepared to recognize as ‘reasonable.’” Id. at 361. ") The Court stated: “What a person knowingly exposes to the public, even in his own home or office, is not a subject of Fourth Amendment protection. But what he seeks to preserve as private, even in an area accessible to the public, may be constitutionally protected.” [4](https://www.law.cornell.edu/constitution-conan/amendment-4/katz-and-reasonable-expectation-of-privacy-test#fn4amd4 " 389 U.S. at 351–52. ") That is, the “capacity to claim the protection of the Amendment depends not upon a property right in the invaded place but upon whether the area was one in which there was reasonable expectation of freedom from governmental intrusion.” [5](https://www.law.cornell.edu/constitution-conan/amendment-4/katz-and-reasonable-expectation-of-privacy-test#fn5amd4 " Mancusi v. DeForte, 392 U.S. 364, 368 (1968) (official had a reasonable expectation of privacy in an office he shared with others, although he owned neither the premises nor the papers seized). Minnesota v. Olson, 495 U.S. 91 (1990) (overnight guest in home has a reasonable expectation of privacy). But cf. Minnesota v. Carter, 525 U.S. 83 (1998) (a person present in someone else’s apartment for only a few hours for the purpose of bagging cocaine for later sale has no legitimate expectation of privacy); Cf. Rakas v. Illinois, 439 U.S. 128 (1978) (auto passengers demonstrated no legitimate expectation of privacy in glove compartment or under seat of auto). The Fourth Amendment protects property rights however. A “seizure” of property can occur when there is some meaningful interference with an individual’s possessory interests in that property, and regardless of whether there is any interference with the individual’s privacy interest. Soldal v. Cook County, 506 U.S. 56 (1992) (a seizure occurred when sheriff’s deputies assisted in the disconnection and removal of a mobile home in the course of an eviction from a mobile home park). The reasonableness of a seizure, however, is an additional issue that may still hinge on privacy interests. United States v. Jacobsen, 466 U.S. 109, 120–21 (1984) (DEA agents reasonably seized package for examination after private mail carrier had opened the damaged package for inspection, discovered presence of contraband, and informed agents). ")

In Kyllo v. United States,[6](https://www.law.cornell.edu/constitution-conan/amendment-4/katz-and-reasonable-expectation-of-privacy-test#fn6amd4 " 533 U.S. 27 (2001). ") the Court revitalized Katz's focus on privacy when it invalidated the warrantless use of a thermal imaging device directed at a private home from a public street. To limit police use of new technology that can “shrink the realm of guaranteed privacy,” the Court stated that “obtaining by sense-enhancing technology any information regarding the interior of the home that could not otherwise have been obtained without physical ‘intrusion into a constitutionally protected area’ . . . constitutes a search—at least where (as here) the technology in question is not in general public use.” [7](https://www.law.cornell.edu/constitution-conan/amendment-4/katz-and-reasonable-expectation-of-privacy-test#fn7amd4 " Id. at 34. ") Relying on Katz, the Court rejected as “mechanical” the Government’s attempted distinction between off-the-wall and through-the-wall surveillance. Permitting all off-the-wall observations, the Court observed, “would leave the homeowner at the mercy of advancing technology—including technology that could discern all human activity in the home.” To some extent, the Court grounded its concern about privacy expectations in “Founding-era understandings,” [8](https://www.law.cornell.edu/constitution-conan/amendment-4/katz-and-reasonable-expectation-of-privacy-test#fn8amd4 " Carpenter v. United States, No. 16-402, slip op. at 6 (U.S. June 22, 2018). ") explaining that the Fourth Amendment “seeks to secure ‘the privacies of life’ against ‘arbitrary power,’” [9](https://www.law.cornell.edu/constitution-conan/amendment-4/katz-and-reasonable-expectation-of-privacy-test#fn9amd4 " Id. (quoting Boyd v. United States, 116 U.S. 616, 630 (1886)). ") and that “a central aim of the Framers was ‘to place obstacles in the way of a too permeating police surveillance.’” [10](https://www.law.cornell.edu/constitution-conan/amendment-4/katz-and-reasonable-expectation-of-privacy-test#fn10amd4 " Id. (quoting United States v. Di Re, 332 U.S. 581, 595 (1948)). ")

Although the Court strongly reaffirmed the sanctity of the home, protection of privacy in other contexts became more problematic. A two-part test that Justice John Harlan suggested in Katz often provided a starting point for analysis.[11](https://www.law.cornell.edu/constitution-conan/amendment-4/katz-and-reasonable-expectation-of-privacy-test#fn11amd4 " Justice John Harlan’s opinion has been much relied upon. See, e.g., Terry v. Ohio, 392 U.S. 1, 19 (1968); Rakas v. Illinois, 439 U.S. 128, 143–144 n.12 (1978); Smith v. Maryland, 442 U.S. 735, 740–41 (1979); United States v. Salvucci, 448 U.S. 83, 91–92 (1980); Rawlings v. Kentucky, 448 U.S. 98, 105–06 (1980); Bond v. United States, 529 U.S. 334, 338 (2000). ") The first element, the “subjective expectation” of privacy, has largely dwindled as a viable standard, because, as Justice John Harlan noted in a subsequent case, “our expectations, and the risks we assume, are in large part reflections of laws that translate into rules the customs and values of the past and present.” [12](https://www.law.cornell.edu/constitution-conan/amendment-4/katz-and-reasonable-expectation-of-privacy-test#fn12amd4 " United States v. White, 401 U.S. 745, 786 (1971). See Smith, 442 U.S. at 740 n.5 (government could not condition “subjective expectations” by, say, announcing that henceforth all homes would be subject to warrantless entry, and thus destroy the “legitimate expectation of privacy” ). ") As for the second element, whether one has a “legitimate” expectation of privacy that society finds “reasonable” to recognize, the Court has said that “[l]egitimation of expectations of privacy by law must have a source outside of the Fourth Amendment , either by reference to concepts of real or personal property law or to understandings that are recognized and permitted by society.” [13](https://www.law.cornell.edu/constitution-conan/amendment-4/katz-and-reasonable-expectation-of-privacy-test#fn13amd4 " Rakas, 439 U.S. at 144 n.12. ")

Thus, protecting the home is at the apex of Fourth Amendment coverage because of the right associated with ownership to exclude others;[14](https://www.law.cornell.edu/constitution-conan/amendment-4/katz-and-reasonable-expectation-of-privacy-test#fn14amd4 " E.g., Alderman v. United States, 394 U.S. 165 (1969); Mincey v. Arizona, 437 U.S. 385 (1978); Payton v. New York, 445 U.S. 573 (1980); Kyllo v. United States, 533 U.S. 27, 31 (2001). ") but ownership of other things, that is, automobiles, does not carry a similar high degree of protection.[15](https://www.law.cornell.edu/constitution-conan/amendment-4/katz-and-reasonable-expectation-of-privacy-test#fn15amd4 " E.g., United States v. Ross, 456 U.S. 798 (1982). See also Donovan v. Dewey, 452 U.S. 594 (1981) (commercial premises); Maryland v. Macon, 472 U.S. 463 (1985) (no legitimate expectation of privacy in denying to undercover officers allegedly obscene materials offered to public in bookstore). ") The Court usually considers whether a person has taken normal precautions to maintain his privacy—that is, precautions customarily taken by those seeking to exclude others—to be significant when determining legitimacy of expectation.[16](https://www.law.cornell.edu/constitution-conan/amendment-4/katz-and-reasonable-expectation-of-privacy-test#fn16amd4 " E.g., United States v. Chadwick, 433 U.S. 1, 11 (1977); Katz v. United States, 389 U.S. 347, 352 (1967). But cf. South Dakota v. Opperman, 428 U.S. 364 (1976) (no legitimate expectation of privacy in automobile left