Warrantless GPS tracking will make its way to the Supreme Court this week, when the justices are scheduled to hear oral arguments in U.S. v. Jones.
The court will consider whether police must first obtain a warrant before placing a GPS device on a suspect's car. More specifically, the Court is tasked with deciding whether the Fourth Amendment bans warrantless GPS tracking when it lasts for an entire month.
The D.C. Circuit decided that such a practice is unconstitutional. The difference between GPS tracking and other types of technology, it explained, is that police can track every place an individual goes.
From that data, police can determine "whether a person is a weekly church goer, a heavy drinker, a regular at the gym, an unfaithful husband, an outpatient receiving medical treatment, an associate of particular individuals or political groups."
But the Justice Department appealed, and believes that drivers have no expectation of privacy when they travel across public roads. They don't expect their movements to be kept private.
On some level, this is true, which is why police don't need a warrant to tail a suspect for a month and follow his every move. But do people have an expectation that a tracking device will not be planted on their car?
This is the very tension at issue in this case, according to legal scholar Erwin Chemerinsky. When does monitoring of arguably public activity become so intrusive as to require a warrant under the Fourth Amendment?
The Supreme Court's answer is perhaps the most important opinion it will release this term. How it rules on warrantless GPS tracking will directly impact the way law enforcement uses new technologies, including cell phones and other wireless devices.