EPIC, Restore the Fourth File Amicus Brief in Chatrie v. United States Urging the Fourth Circuit to Rule Geofence Warrant Unconstitutional

This week, EPIC and Restore the Fourth filed an amicus brief in the Fourth Circuit case Chatrie v. United States explaining why the Court should rule that the geofence search in the case was an unconstitutional general warrant because it lacked particularized probable cause. The brief traces the history of the Fourth Amendment, common law, and state constitutional conventions to demonstrate why general warrants were so reviled by the founders and why the geofence warrant in this case is a general warrant.

Geofence searches are a controversial investigative technique in which government officers require companies such as Google to tell them everyone whose device was within a certain area (a geofence) within a certain timeframe. These companies’ vast collections of users’ location history data provide a rich target for investigators. Geofence searches raise serious privacy and Fourth Amendment questions, and federal courts of appeals have split on the issue of whether the searches (and warrants permitting them) are constitutional.

The Chatrie case is back in the Fourth Circuit after the Supreme Court issued a landmark ruling declaring that geofence searches require a warrant—a result urged by an EPIC-authored amicus brief on behalf of law & technology scholars. Now that it is established that geofence searches require a warrant, the Fourth Circuit will analyze whether the warrant supporting the search met constitutional requirements.

EPIC regularly advocates for privacy protections from government surveillance and consumer privacy laws that would reduce the privacy threat posed by techniques such as geofence warrants.