An overlapping array of justices were divided on the rationale for the decision, with the majority saying the problem was the placement of the device on private property.

But five justices also discussed their discomfort with the government’s use of or access to various modern technologies, including video surveillance in public places, automatic toll collection systems on highways, devices that allow motorists to signal for roadside assistance, location data from cellphone towers and records kept by online merchants.

The case concerned Antoine Jones, who was the owner of a Washington nightclub when the police came to suspect him of being part of a cocaine-selling operation. They placed a tracking device on his Jeep Grand Cherokee without a valid warrant, tracked his movements for a month and used the evidence they gathered to convict him of conspiring to sell cocaine. He was sentenced to life in prison.

The United States Court of Appeals for the District of Columbia Circuit overturned his conviction, saying the sheer amount of information that had been collected violated the Fourth Amendment, which bars unreasonable searches. “Repeated visits to a church, a gym, a bar or a bookie tell a story not told by any single visit, as does one’s not visiting any of those places in the course of a month,” Judge Douglas H. Ginsburg wrote for the appeals court panel.

The Supreme Court affirmed that decision, but on a different ground. “We hold that the government’s installation of a GPS device on a target’s vehicle, and its use of that device to monitor the vehicle’s movements, constitutes a ‘search,’ ” Justice Antonin Scalia wrote for the majority. Chief Justice John G. Roberts Jr. and Justices Anthony M. Kennedy, Clarence Thomas and Sonia Sotomayor joined the majority opinion.