Whether attaching a GPS device to a vehicle and using it to monitor the vehicle’s movements on public streets is a Fourth Amendment search.
Holding
Yes. The Government conducted a search by physically occupying Jones’s vehicle, an “effect,” to obtain information.
Reasoning
The Fourth Amendment protects the people in their “persons, houses, papers, and effects,” and a vehicle is plainly an effect. By attaching the GPS tracker to the Jeep while Jones possessed and exclusively drove it, agents physically intruded on a constitutionally protected item of personal property for the purpose of gathering information about his movements. That combination of a physical intrusion and information gathering constituted a search.
The Court treated this conclusion as consistent with the original understanding of the Fourth Amendment. At common law, an unauthorized entry onto another’s protected property was a trespass, and the Amendment was centrally concerned with government intrusions on the enumerated protected areas. The Government’s physical occupation of Jones’s Jeep to obtain data therefore fell within the Amendment’s historical core.
Katz v. United States added the reasonable-expectation-of-privacy framework, but it did not eliminate the older property-based protection. Fourth Amendment rights do not rise or fall solely with Katz. A trespassory intrusion on a person, house, paper, or effect for the purpose of obtaining information remains independently sufficient to establish a search.
The Government’s reliance on United States v. Knotts and United States v. Karo was misplaced. In those beeper cases, the tracking device was placed in a container before it came into the defendant’s possession, with the then-owner’s consent. Jones, in contrast, possessed the Jeep when the Government physically attached its device. Likewise, the fact that the Jeep’s locations on public roads were observable did not excuse the physical encroachment used to collect that information.
The Court did not decide whether prolonged GPS monitoring without a physical trespass would violate a reasonable expectation of privacy under Katz. Nor did it decide the duration of electronic tracking that might become constitutionally problematic absent a trespass. Those questions were unnecessary because the physical intrusion on Jones’s vehicle supplied a narrower ground for decision.