Today, Mozilla has joined other major technology companies in filing an amicus brief urging the Supreme Court of the United States to reexamine how the 4th Amendment and search warrant requirements should apply in our digital era. We are joining this brief because we believe our laws need to keep up with what we already know to be true: that the Internet is an integral part of modern life, and that user privacy must not be treated as optional.

At the heart of this case is the government’s attempt to obtain “cell site location information” to aid in a criminal investigation. This information is generated continuously when your phone is on. Your phone communicates with nearby cell sites to connect with the cellular network and those sites create a record of your phone’s location as you go about your business. In the case at hand, the government did not obtain a warrant, which would have required probable cause, before obtaining this location information. Instead, the government sought a court order under the Stored Communications Act of 1986, which requires a lesser showing.

Looking at how the courts have dealt with the cell phone location records in this case demonstrates why our laws must be revisited to account for modern technological reality. The district court decided that the government didn’t have to obtain a warrant because people do not have a reasonable expectation of privacy in their cell phone location information. On appeal, the Sixth Circuit acknowledged that similar information, such as GPS monitoring in government investigations, would require a warrant. But it too found no warrant was needed because the location information was a “business record” from a “third party” (i.e., the service providers).

We believe users should not be forced to surrender their expectations of privacy when using their phones and we hope the Court will reconsider the law in this area.

*Brief link updated on August 16