Which case established limits on surveillance and privacy in modern search technologies?

• A. Riley v. California
• B. Katz v. United States
• C. United States v. Jones
• D. Kyllo v. United States

Answer: (D)

The main idea is that the Fourth Amendment protects privacy against intrusive surveillance when new technologies can reveal private details inside the home. This case shows how courts draw the line around modern tools that probe into intimate spaces.

In this decision, the police used a thermal-imaging device to detect heat patterns from a private home to look for illicit activity. The Court held that using such a device to discover information about the interior of a home constitutes a search. Because the technique was not in general public use at the time, obtaining the information with that specialized technology required a warrant based on probable cause. The ruling emphasizes that the privacy of the home is protected from evolving surveillance methods that uncover private details without the occupant’s consent or a warrant.

Other choices point to related privacy ideas but not this specific limitation on modern surveillance in the home. Riley deals with privacy of data on a cell phone seized during an arrest, Katz lays groundwork about a reasonable expectation of privacy, and United States v. Jones concerns GPS tracking on a vehicle. None of these establish the particular boundary that thermal imaging of a home without a warrant violates the Fourth Amendment.