Which case established that warrants are necessary for intercepting private conversations in public?

The case that established that warrants are necessary for intercepting private conversations in public is Katz v. United States. This landmark decision, issued by the Supreme Court in 1967, fundamentally changed the understanding of privacy in the context of electronic surveillance.

In Katz v. United States, the Court ruled that the Fourth Amendment protects people, not merely places, which means that individuals have a reasonable expectation of privacy even in public spaces when engaging in private conversations. This case emphasized that the government must obtain a warrant based on probable cause before conducting any wiretapping or electronic eavesdropping on a private conversation, reinforcing the idea that privacy rights extend to conversations conducted in public areas if there is a reasonable expectation of privacy.

This ruling has significant implications for the practices of private investigators and law enforcement, establishing a clear guideline that protects individual privacy against unwarranted government intrusion. It defined the legal boundaries regarding surveillance and set a precedent that continues to influence how privacy rights are interpreted and enforced in the United States.