Overturning an important precedent that had endured for almost forty years, this Supreme Court ruling significantly expanded Fourth Amendment rights in ruling that police must obtain warrants before wiretapping private conversations, even inside public telephone booths.
In Olmstead v. United States
Justice Potter Stewart's majority opinion in Katz helped expand Fourth Amendment protections.
Around that same time, federal agents attached an electronic listening device to the outside of a public phone booth frequently used by bookmaker Charles Katz. The conversations overheard by the officers were used in his criminal trial. Katz argued that the listening devices violated his Fourth Amendment protection against illegal searches. The lower courts, referring to Olmstead and Silverman, concluded that no search had occurred, because no tangible object was involved and the wall of the booth had not been physically penetrated.
By a 7-1 margin, however, the Supreme Court ruled in Katz’s favor. Delivering the opinion for the Court, Justice Potter Stewart
The seminal Katz ruling, as interpreted in Harlan’s concurrence, provided the standard for deciding countless later Fourth Amendment cases. The Court, however, has tended to take a relatively narrow interpretation of the concept “reasonable expectation of privacy.” For example, it found that a person had no reasonable expectation of privacy in bank records in United States v. Miller
Kyllo v. United States
Mapp v. Ohio
Privacy, right to
Search warrant requirement