In a landmark decision for the freedoms of speech and association as well as digital privacy, the Supreme Court today ruled in Carpenter v. United States that the government may not acquire certain cellphone location data without a warrant. Last fall, the Knight First Amendment Institute at Columbia University filed an amicus brief in Carpenter on behalf of leading technology experts, explaining that cellphone location data reveals extraordinarily sensitive information about one’s movements and associations.

The following statement is attributable to Alex Abdo, senior staff attorney at the Knight Institute:

“This ruling is a landmark for privacy rights — and also for the freedoms of speech and association. As the Court recognizes, new technology has given the government the ability to construct a detailed chronicle of the movements of nearly every American for a period of years. Left unchecked, this kind of surveillance will deter the exercise of core democratic rights. Today’s ruling places important limits on the government’s surveillance power. Perhaps even more important, the ruling charts a course for the Court's evaluation of the government’s use of other digital-age technologies.”

Read the Supreme Court's decision.

Read the Knight Institute’s amicus brief in Carpenter.