The expansion of a reasonable expectation of privacy to include electronic surveillance originated from which case?

• A. Mapp v. Ohio
• B. Roe v. Wade
• C. Plessy v. Ferguson
• D. Katz v. United States

Answer: (D)

The main concept tested is how the Fourth Amendment’s privacy protections were extended to cover electronic surveillance. Katz v. United States is the case that began this expansion. The Court rejected the idea that the Fourth Amendment only protects physical spaces like a home; it said the Fourth Amendment protects people, not places, and introduced the reasonable expectation of privacy test. If a person has a subjective expectation of privacy and society recognizes that expectation as reasonable, then government conduct that intrudes on that expectation is a search and generally requires a warrant. In Katz, tapping a public phone booth to listen to a private conversation violated this standard, marking the start of broader protections against electronic eavesdropping.

The other cases don’t address this expansion: Mapp v. Ohio concerns applying the exclusionary rule to the states, Roe v. Wade centers on reproductive privacy, and Plessy v. Ferguson deals with racial segregation. Thus, Katz v. United States is the ruling that origin of this privacy expansion.