The justices agreed police violated Jones' rights but disagreed on just why.
The Constitution's Fourth Amendment says, "The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated."
Antonin Scalia wrote for a five-vote majority that a person's property is legally sacred, and the government had to justify placing a GPS device on the vehicle. Scalia said the electronic age does not change a centuries-old concept.
"The government physically occupied private property for the purpose of obtaining information," said the ruling. "We have no doubt that such a physical intrusion would have been considered a 'search' within the meaning of the Fourth Amendment when it was adopted."