What aspect of a search did the Katz case address?

The Katz case fundamentally changed the way courts interpret the Fourth Amendment concerning searches and seizures by establishing the principle of a reasonable expectation of privacy. Prior to this case, the focus was heavily on physical intrusion as a measure of a search. Katz demonstrated that individuals have a privacy interest in their conversations, regardless of whether a physical trespass occurred.

In this case, the Supreme Court ruled that the government's recording of a telephone conversation, conducted from a public phone booth, constituted a search under the Fourth Amendment, even though there was no physical entry into the booth. This decision highlighted that the Fourth Amendment protects people, not just places, and set the standard for evaluating privacy under the law. Therefore, the key takeaway from Katz is that the determination of a search is based on whether an individual has a reasonable expectation of privacy in the situation at hand.