The government’s installation of a GPS tracking device on a vehicle and its use of that device to monitor the vehicle’s movements on public streets constitutes a “search” within the meaning of the Fourth Amendment. Suspecting that the defendant was involved in drug trafficking, the government obtained a search warrant for use of a GPS device on the defendant’s vehicle; the warrant authorized officers to install the device in the District of Columbia within 10 days. Officers ended up installing the device on the undercarriage of the vehicle while it was parked in a public parking lot in Maryland, 11 days after the warrant was signed. Over the next 28 days, the government used the device to track the vehicle’s movements, and once had to replace the device’s battery when the vehicle was parked in a different public lot in Maryland. By means of signals from multiple satellites, the device established the vehicle’s location within 50 to 100 feet, and communicated that location by cellular phone to a government computer. It relayed more than 2,000 pages of data over the 4-week period. The defendant was charged with several drug offenses. He unsuccessfully sought to suppress the evidence obtained through the GPS device. Before the U.S. Supreme Court the government conceded noncompliance with the warrant and argued only that a warrant was not required for the GPS device. Concluding that the evidence should have been suppressed, the Court characterized the government’s conduct as having “physically occupied private property for the purpose of obtaining information.” So characterized, the Court had “no doubt that such a physical intrusion would have been considered a ‘search’ within the meaning of the Fourth Amendment when it was adopted.” The Court declined to address whether the defendant had a reasonable expectation of privacy in the undercarriage of his car and in the car’s locations on the public roads, concluding that such an analysis was not required when the intrusion—as here—“encroached on a protected area.”