Why did Antonin Scalia rule against warrantless GPS tracking in United States v. Jones?

In United States v. Jones (2012), Justice Antonin Scalia authored the majority opinion, which held that the government’s attachment of a GPS device to a vehicle to track a suspect’s movements constituted an unconstitutional search under the Fourth Amendment.1

Scalia’s ruling was grounded in his commitment to originalism, which emphasizes the original public meaning of constitutional text at the time of its ratification. He reasoned that the Fourth Amendment protects the right of the people to be secure in their "persons, houses, papers, and effects" against unreasonable searches. By physically installing the device on the vehicle—a form of "effect"—the government had committed a common-law trespass, which Scalia identified as a search within the original meaning of the Fourth Amendment.12

This approach focused on the physical intrusion into a constitutionally protected area, rather than relying solely on evolving expectations of privacy. By anchoring the decision in historical practice and the literal text of the Constitution, Scalia sought to limit judicial discretion and ensure that constitutional protections remain fixed and predictable.1