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Katz v. United States, 389 U.S. 347 (1967) (full-text).

Factual Background[]

Katz was a bookie convicted on the basis of evidence gathered by an electronic listening and recording device set up outside the public telephone booth that Katz used to take and place bets.

U.S. Supreme Court Proceedings[]

The Supreme Court reversed Olmstead v. United States[1] and held that FBI agents violated the Fourth Amendment by installing an "electronic listening and recording device" on the outside of a telephone booth to record calls being made by Katz.

The Court held that the gateway for Fourth Amendment purposes stood at that point where an individual should to able to expect that his or her privacy would not be subjected to unwarranted governmental intrusion.[2]

The majority overruled Olmstead v. United States, explaining that "once it is recognized that the Fourth Amendment protects people — and not simply 'areas' — against unreasonable searches and seizures, it becomes clear that the reach of that Amendment cannot turn upon the presence or absence of a physical intrusion into any given enclosure."[3]

We conclude that the underpinnings of Olmstead and Goldman have been so eroded by our subsequent decisions that the trespass doctrine there enunciated can no longer be regarded as controlling. The Government’s activities in electronically listening to and recording the petitioner’s words violated the privacy upon which he justifiably relied while using the telephone booth and thus constituted a search and seizure within the meaning of the Fourth Amendment. The fact that the electronic device employed to achieve that end did not happen to penetrate the wall of the booth can have no constitutional significance. [4]

Harlan's Concurring Opinion[]

In a concurrence, Justice Harlan articulated the standard that has been used to implement the Katz holding:

As the Court's opinion states, "the Fourth Amendment protects people, not places." The question . . . is what protection it affords to those people. . . . My understanding of the rule that has emerged from prior decisions is that there is a twofold requirement, 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 aa "reasonable." Thus a man's home is, for most purposes, a place where he expects privacy. . . . On the other hand, conversations in the open would not be protected against being overheard, for the expectation of privacy under the circumstances would be unreasonable.[5]


  1. 277 U.S. 438 (1928) (full-text).
  2. 389 U.S. at 353.
  3. Id. at 353.
  4. Id. at 361.
  5. Id. at 361 (Harlan, J., concurring).

See also[]