agreed to hear his case and granted certiorari. Opinion of the court On December 18, 1967, the Supreme Court issued a 7–1 decision in favor of Katz that invalidated the FBI's wiretap evidence and overturned Katz's criminal conviction. The majority opinion was written by Justice Potter Stewart. The Court began by dismissing the parties' characterization of the case in terms of traditional trespass-based analysis that hinged on, first, whether the public telephone booth Katz had used was a "constitutionally protected area" where he had a "right of privacy"; and second, on whether the FBI had "physically penetrated" the protected area and thus violated the Fourth Amendment. Instead, the Court viewed the situation through the lens of how Katz's use of the phone booth would be perceived by himself and then objectively by others. In a now well-known passage, Stewart wrote: The Supreme Court then briefly surveyed the history of American jurisprudence on governmental searches and seizures. It described how American courts had traditionally analyzed Fourth Amendment searches by analogizing them to the long-established doctrine of trespass. In their legal briefs, the parties had focused on the 1928 precedent Olmstead v. United States, in which the Court ruled that surveillance by wiretap without any trespass did not constitute a "search" for Fourth Amendment purposes. However, the Court stated that in later cases it had begun recognizing that the Fourth Amendment applied to recorded speech obtained without any physical trespassing, and that the law had evolved. Stewart wrote: Stewart then concluded the Court's opinion by ruling that even though the FBI knew there was a "strong probability" that Katz was breaking the law when using the phone booth, their use of the wiretap was an unconstitutional search because they did not obtain a warrant before placing the listening device. Harlan's concurrence Justice John Marshall Harlan II's concurring opinion in Katz has become even more influential than the majority opinion. It describes a two-part test which has come to be known as the Katz test. Harlan began his opinion by noting that he was writing separately to elaborate on the meaning of Stewart's majority opinion. Harlan explained that he interpreted Stewart's statements that "the Fourth Amendment protects people, not places" and "what a person knowingly exposes to the public [...] is not a subject of Fourth Amendment protection" to mean that the Fourth Amendment is activated any time a person has an expectation