Katz is best known for establishing which legal concept?

• A. Search and seizure rules
• B. Reasonable Expectation of Privacy
• C. Exploratory search
• D. Trespass to chattels

Answer: (B)

The key idea here is the reasonable expectation of privacy under the Fourth Amendment. Katz v. United States established that Fourth Amendment protection isn’t about a person’s place alone but about the person’s privacy expectations. In that case, the government listened to Katz’s private phone call from a public payphone, and the Court said Katz had a legitimate expectation of privacy in the contents of his conversation, even though no physical trespass occurred. The ruling introduces a two-part test: there must be a subjective expectation of privacy, and society must recognize that expectation as reasonable. This shifts the focus from trespass onto property to protecting personal privacy in communications, a framework that still guides how privacy is treated in digital contexts today. The other options don’t fit because they refer to different legal concepts: trespass to chattels is a tort about interfering with someone’s property, exploratory search isn’t a recognized legal doctrine in this context, and general search and seizure rules are too broad without the privacy-focused standard Katz established.