Which case established the 'reasonable expectation of privacy' test for searches?

• A. Lau v. Nichols
• B. Katz v. United States
• C. Garcetti v. Ceballos
• D. Schenck v. United States

Answer: (B)

The key idea is that the Fourth Amendment protects people based on their privacy expectations, not simply on where they are. Katz v. United States established the test that determines whether a government intrusion constitutes a search by looking at two things: whether the person actually expected privacy in the situation, and whether that expectation is one society is prepared to recognize as reasonable. In that decision, tapping a private conversation in a public phone booth was considered a search because people reasonably expect their conversations to remain private, even when they are in public, so a warrant is required for such surveillance. This case shifted the focus from physical trespass to a privacy-based standard for searches and electronic surveillance. The other listed cases deal with different constitutional issues—education rights in Lau v. Nichols, public employee speech in Garcetti v. Ceballos, and wartime speech limits in Schenck v. United States—so they don’t establish the privacy-test framework.