United States v. Jones
The Court ruled that police physically attaching a GPS tracking device to a suspect's car, and using it to monitor his movements for weeks, counts as a "search" under the Fourth Amendment.
Because officers had physically placed the device on the car without a valid warrant, the search was unlawful, and the Court's approach revives the idea that physically invading someone's property to gather information is itself a constitutional trigger, separate from the modern 'reasonable expectation of privacy' test.
“The Government physically occupied private property for the purpose of obtaining information.”
The core reasoning for why attaching the GPS device was a Fourth Amendment search.
How it got here: A federal jury convicted Jones using the GPS evidence; the D.C. Circuit reversed, finding the warrantless GPS tracking unconstitutional; the government sought Supreme Court review.
The Case in Depth
What happened
Antoine Jones, a nightclub owner in Washington, D.C., came under suspicion of drug trafficking. Investigators obtained a warrant to install a GPS tracker on a Jeep he drove, but installed it late and outside the area the warrant allowed. Agents then tracked the vehicle's movements for four weeks, gathering data used to help convict Jones of conspiracy to distribute cocaine, resulting in a life sentence.
The question before the Court
Did police need a warrant to secretly attach a GPS tracker to a suspect's car and monitor his movements for weeks?
Why it matters
Police departments nationwide now need a warrant before physically installing tracking devices on vehicles or other personal property to gather evidence. The ruling also signals that lower courts and Congress may need to grapple separately with GPS and cellphone tracking that doesn't involve physically touching a suspect's property.
What changes now
This is a final merits decision, not a temporary order. The D.C. Circuit's reversal of Jones's conviction stands, meaning prosecutors could not use the GPS evidence against him. The ruling leaves open how the Fourth Amendment applies to tracking methods that don't involve physically touching a suspect's property, such as cellphone location data, an issue the concurring opinions flagged as needing future resolution.
What this does not decide
The Court expressly did not decide whether long-term electronic tracking accomplished without any physical trespass — such as through built-in car GPS systems or smartphones — would also violate the Fourth Amendment. It also did not decide whether the search here would have been reasonable if the government had preserved that argument.
Concurrences and dissents
Concurrence — Justice Sotomayor
Justice Sotomayor joined the majority's trespass-based holding but wrote separately to stress that the Fourth Amendment also protects against non-trespassory invasions of privacy under Katz. She argued that GPS monitoring reveals an enormous amount of sensitive information cheaply and secretly, and suggested it may be time to reconsider the rule that information voluntarily shared with third parties loses all privacy protection.
Concurrence — Justice Alito
“It strains the language of the Fourth Amendment; it has little if any support in current Fourth Amendment case law; and it is highly artificial.”Alito's objection to the majority's reliance on old trespass law rather than privacy expectations.
Justice Alito agreed the search was unconstitutional but rejected the majority's trespass-based reasoning as artificial and inconsistent with modern Fourth Amendment law. He would have decided the case entirely under the reasonable-expectation-of-privacy test, concluding that four weeks of GPS tracking crossed the line into a search regardless of any physical touching, while shorter-term monitoring might not.
How the Court got there
The legal reasoning, step by step
- The Court asked whether physically placing a tracking device on someone's property to gather information counts as a 'search,' starting from the Fourth Amendment's text protecting 'persons, houses, papers, and effects' against unreasonable searches.
- The Court traced Fourth Amendment law back to its historical roots in trespass law, explaining that before the 1960s courts asked whether the government had physically intruded on protected property, not merely whether privacy was invaded.
- The Court held that the 1967 case Katz v. United States, which asks whether the government violated someone's 'reasonable expectation of privacy,' added a second way to find a search but did not eliminate the older trespass-based approach.
- Applying the trespass test, the Court found that physically attaching the GPS device to the Jeep and using it to gather location data was exactly the kind of physical intrusion onto a person's property, for the purpose of getting information, that qualified as a search at the time the Fourth Amendment was adopted.
- The Court distinguished prior 'beeper' tracking cases, explaining those devices had been installed before the defendant possessed the property (with the then-owner's consent), so no trespass against the defendant's own possessory interest had occurred there.
- Because the government conceded it had not complied with the warrant's location and timing conditions, and did not argue below that the search was otherwise reasonable, the Court treated that reasonableness argument as forfeited and left the finding of an unlawful search intact.
Doctrinal impact
Cases affected by this decision
Limits Katz v. United States (389 U.S. 347)
The Court held Katz's privacy test added to, but did not replace, the older trespass-based search test.
Distinguishes United States v. Knotts (460 U.S. 276)
The Court said Knotts only addressed privacy expectations, not the trespass issue raised by this case.
Distinguishes United States v. Karo (468 U.S. 705)
The Court found Karo involved a beeper installed before the defendant possessed the container, unlike Jones's situation.
Distinguishes Olmstead v. United States (277 U.S. 438)
The Court noted Olmstead found no search because wiretaps never physically entered the defendants' property.