What is the general principle established by the Katz v US decision regarding privacy?

The principle established by the Katz v. US decision centers on the expectation of privacy people have in their personal effects and communications. The ruling clarified that the Fourth Amendment protects people, not just physical places or property. Katz emphasized that individuals have a reasonable expectation of privacy when they are in situations where they do not intend for their conversations or communications to be overheard or intercepted.

This case set a precedent that the nature of privacy extends beyond physical property, recognizing that the law must adapt to changing technology and society's understanding of privacy. For instance, even if someone is in a public space, they can still have an expectation of privacy if they are conducting a private conversation, which is reflective of the broader, more inclusive interpretation of personal privacy rights. This points out that the privacy expectation is tied to people’s actions and the context in which they find themselves, rather than solely to a physical location or possession.