What is a key concept related to privacy established by Katz v. US?

The decision in Katz v. United States established a fundamental principle regarding individuals' expectations of privacy, particularly in the context of phone conversations. In this landmark case, the Supreme Court ruled that the Fourth Amendment protects people, not just areas, and that an individual has a reasonable expectation of privacy in their telephone conversations, even if they are made from a public phone booth.

This case introduced the concept that privacy is not solely determined by physical barriers but also by the subjective expectation of privacy that individuals hold. Therefore, the ruling reinforced that government surveillance must consider this expectation of privacy when conducting searches and seizures. As a result, law enforcement typically needs to obtain a warrant based on probable cause before intercepting private communications. This represents a significant shift in Fourth Amendment jurisprudence, emphasizing the importance of personal privacy in an increasingly connected world.