According to summary data provided to journalist and FOIA ninja Jason Leopold, federal prosecutors’ warrantless surveillance of phone location and internet records grew sevenfold in just the past three years in the District of Columbia.

The demands, called “d orders,” were made under the authority of a 1986 law called the Electronic Communications Privacy Act (ECPA), which allows prosecutors to obtain communications records without warrants as long as prosecutors say they are “relevant and material to an ongoing criminal investigation.” That’s a very low standard—far lower than the warrant standard, which requires that prosecutors show they have probable cause to believe the information sought will prove or relate to criminal activity. Under the “relevant and material” standard, prosecutors can obtain your sensitive information even if you aren’t the target of an investigation. You don’t even have to be suspected of involvement in any criminal activity. And worse still, because of seal and gag provisions, you’ll probably never find out if prosecutors used one of these warrantless demands to access your internet records or location history.

That is, unless the information is used to prosecute you. That’s what happened to ACLU client Timothy Carpenter.

The Supreme Court has taken up his case, and may as a result put an end to at least some of this warrantless surveillance: the location tracking. In the case, United States v. Carpenter, prosecutors used a d order to obtain months of  Mr. Carpenter’s cell phone location records, showing everywhere he went over a period of many weeks. The case is the most significant electronic privacy issue to come before the Court since it ruled in 2014 that police must obtain a warrant to search a cell phone incident to arrest.