WASHINGTON WASHINGTON The Supreme Court on Monday unanimously ruled that the police violated the Constitution when they placed a Global Positioning System tracking device on a suspect's car and monitored its movements for 28 days.
But the justices divided 5-4 on the rationale for the decision, with the majority saying the problem was the placement of the device on private property. That ruling avoided many difficult questions, including how to treat information gathered from devices installed by the manufacturer and how to treat information held by third parties like.
Walter Dellinger, a lawyer for the defendant in the case and a former acting U.S. solicitor general, said the decision "is a signal event in Fourth Amendment history."
"Law enforcement is now on notice," he said, "that almost any use of GPS electronic surveillance of a citizen's movement will be legally questionable unless a warrant is obtained in advance."
Although the ruling was limited to physical intrusions, the opinions in the case collectively suggested a majority of the justices are prepared to apply broad Fourth Amendment privacy principles unrelated to such intrusions to an array of modern technologies, including video surveillance in public places and records kept by online merchants.
The case decided Monday, United States v. Jones, No. 10-1259, 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 U.S. 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. 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.
In a concurrence , Justice Samuel A. Alito Jr. faulted the majority for trying to apply 18th-century legal concepts to 21st-century technologies. What should matter, he said, is the contemporary reasonable expectation of privacy.
Scalia added that the majority did not mean to suggest its property-rights theory of the Fourth Amendment displaced the one focused on expectations of privacy.
