Block on Trump's Asylum Ban Upheld by Supreme Court
In a detailed 5- 4 opinion, the High Court basically proclaimed the following rule when it comes to law enforcement obtaining an individual's cell phone location data:
Before compelling a wireless carrier to turn over a subscriber's CSLI, the Government's obligation is a familiar one -- get a warrant.
In Carpenter v. U.S., Justice Roberts, for the majority, stressed the fact that individuals have a privacy interest in their cell phone location data, and that absent probable cause and a warrant, or exigent circumstances, it cannot be searched by law enforcement.
As Justice Roberts explained, the Court had "to apply the Fourth Amendment to a new phenomenon." The opinion makes clear that cell phone location data goes beyond GPS, that it's "detailed, encyclopedic, and effortlessly compiled." Specifically, he described how "wireless carriers already have the capability to pinpoint a phone's location within 50 meters."
Curiously, the location data in Carpenter was obtained using a predetermined process to obtain it. Unfortunately, the Court ruled that the process did not adequately safeguard Carpenter's Fourth Amendment reasonable expectation of privacy as the standard for permitting the search did not require probable cause.
Carpenter Threads a Needle
As Roberts emphasizes throughout the majority's brief opinion, the Court's holding is rather narrow and should not be applied to broader contexts:
We do not express a view on matters not before us: real-time CSLI or "tower dumps" (a download of information on all the devices that connected to a particular cell site during a particular interval). We do not disturb the application of Smith and Miller or call into question conventional surveillance techniques and tools, such as security cameras. Nor do we address other business records that might incidentally reveal location information. Further, our opinion does not consider other collection techniques involving foreign affairs or national security. As Justice Frankfurter noted when considering new innovations in airplanes and radios, the Court must tread carefully in such cases, to ensure that we do not "embarrass the future."