The Fourth Amendment's ban on unreasonable searches and seizures applies to all places where an individual has a "reasonable expectation of privacy." Decided December 18, 1967 (argued October 17, 1967). Opinion of the Court: Potter Stewart → go there Dissenting: Black. Applied: the Fourth Amendment → go there Topic: Fourth Amendment rights. Katz v. United States, 389 U.S. 347 (1967), is a landmark decision of the U.S. Supreme Court in which the Court redefined what constitutes a "search" or "seizure" with regard to the Fourth Amendment to the U.S. Constitution. The ruling expanded the Fourth Amendment's protections from an individual's "persons, houses, papers, and effects," as specified in the Constitution's text, to include any areas where a person has a "reasonable expectation of privacy." The reasonable expectation of privacy standard, now known as the Katz test, was formulated in a concurring opinion by Justice John Marshall Harlan II. Wiki link