Which case extended Fourth Amendment protection to include telephone conversations and other forms of electronic communications by applying Katz v. United States?

• A. United States v. Windsor (2013)
• B. Palko v. Connecticut (1937)
• C. Katz v. United States (1967)
• D. Munn v. Illinois (1877)

Answer: (C)

Katz v. United States establishes the key idea that the Fourth Amendment protects people, not just places, by focusing on a person’s reasonable expectation of privacy. In that decision, the Court held that wiretapping a public phone booth violated this privacy expectation, even though there was no physical trespass to the space. The ruling introduces the two-part test: there must be a subjective expectation of privacy, and that expectation must be one that society recognizes as reasonable.

Because electronic communications like telephone conversations are subject to privacy expectations, applying Katz’s framework means government surveillance of those conversations generally requires a warrant. That is why Katz extended Fourth Amendment protection to telephone conversations and other forms of electronic communications.

The other listed cases deal with different topics: one about marriage recognition, another about double jeopardy, and another about economic regulation. They do not address Fourth Amendment privacy or the protection of electronic communications, so they don’t fit this question’s focus.