Answer:
The fourth Amendment that protects people against unreasonable search and seizure, and that requires the police to obtain a search warrant before they could wiretap anything, like a public pay phone.
Explanation:
Katz was caught up transmitting illegal transmission of wagering information over a public phone to clients in other states, but the Federal agents had caught him by attaching an eavesdropping device to the outside of the public phone booth that Katz was using. On Court, Katz argued that the recordings could not be used as evidence against him because it violated the Fourth Amendment right that protected him against unreasonable search and seizure.
The Supreme Court ruled in his favor, stating that tapping a public phone without a warrant violated the Fourth Amendment, and it was a violation of his privacy.
