Katz vs. United States

The Fourth Amendment protects people, not places, and applies whenever a person has a reasonable expectation of privacy—even in a public space—making warrantless electronic eavesdropping an unreasonable search and seizure.

• Katz used a public phone booth to place illegal interstate bets.
• FBI agents attached an electronic listening device to the outside of the booth to record his conversations.
• No physical intrusion into the booth occurred.
• Katz challenged the admissibility of the recordings as Fourth Amendment violations.

• Filed in U.S. District Court for the Southern District of California.
• Katz convicted; evidence from recordings admitted.
• U.S. Court of Appeals for the Ninth Circuit affirmed, finding no Fourth Amendment violation due to lack of physical intrusion.
• U.S. Supreme Court granted certiorari.

• Katz made phone calls from a public glass phone booth.
• FBI agents placed a listening device on the outside of the booth to record his end of conversations.
• Recordings were used as evidence at trial.
• Katz objected, claiming a Fourth Amendment violation.

• A public phone booth is a "constitutionally protected area" when occupied.
• Electronic eavesdropping without physical intrusion still violates the Fourth Amendment.
• The Fourth Amendment protects privacy, not just property.

• No physical penetration of the booth occurred, so no "search or seizure" under existing precedent (Olmstead, Goldman).
• The booth was made of glass, so Katz had no reasonable expectation of privacy.
• Surveillance was limited and justified by probable cause.

• Procedural Issues: N/A
• Substantive Issues:
  • Whether the Fourth Amendment applies to electronic eavesdropping without physical trespass.
  • Whether a person in a public phone booth has a reasonable expectation of privacy.

• Procedural: N/A
• Substantive:
  • The Fourth Amendment’s protections extend to recording oral statements, even without physical intrusion.
  • Katz had a reasonable expectation of privacy in the booth; the government’s eavesdropping violated that expectation.
  • Warrantless electronic surveillance is per se unreasonable unless falling within a few well-delineated exceptions.

• Reasonable Expectation of Privacy Test — A person must exhibit an actual (subjective) expectation of privacy, and that expectation must be one that society recognizes as reasonable. Applied here: Katz shut the booth door and paid to make a call, showing a subjective expectation; society recognizes that phone conversations are private.
• Fourth Amendment Protects People, Not Places — The reach of the amendment depends on whether a person’s reasonable expectation of privacy is violated, not on property-law concepts of trespass.
• Warrant Requirement for Electronic Surveillance — Electronic searches are presumptively unreasonable without a warrant, subject to a few specific exceptions.

• "The Fourth Amendment protects people, not places."
• "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."
• "Searches conducted outside the judicial process, without prior approval by judge or magistrate, are per se unreasonable under the Fourth Amendment—subject only to a few specifically established and well-delineated exceptions."

• Olmstead v. United States, 277 U.S. 438 (1928) — Previously held wiretapping without trespass not covered by Fourth Amendment; overruled by Katz.
• Goldman v. United States, 316 U.S. 129 (1942) — Held electronic eavesdropping without physical intrusion not a search; overruled by Katz.
• Silverman v. United States, 365 U.S. 505 (1961) — Recognized Fourth Amendment extends to oral statements if obtained by physical intrusion.
• Berger v. New York, 388 U.S. 41 (1967) — Struck down a state eavesdropping statute for lack of adequate safeguards.
• Osborn v. United States, 385 U.S. 323 (1966) — Upheld electronic surveillance when authorized by a warrant with precise limits.

• Fourth Amendment, U.S. Constitution — Guarantees right against unreasonable searches and seizures; requires warrants based on probable cause.
• 18 U.S.C. § 1084 — Federal statute prohibiting transmission of wagering information in interstate commerce.

• Justice Harlan (Concurring) — Articulated the two-part test for reasonable expectation of privacy: (1) actual subjective expectation, and (2) one society recognizes as reasonable.
• Justice White (Concurring) — Agreed with the warrant requirement but suggested national security cases might be an exception.
• Justice Douglas (Concurring, joined by Brennan) — Argued against any national security exception to the warrant requirement.

• Justice Black (Dissenting) — Argued the Fourth Amendment’s text only covers tangible "persons, houses, papers, and effects," not conversations; believed the Court was improperly rewriting the Constitution.