Supreme Court to Rule on Police Access to Your Phone Location Data in Landmark Case

Check your pocket. You’re likely carrying a tracking device that allows police—or even the Trump administration—to monitor your every move. If you use a cellphone, you’re constantly revealing your location.

Cellphones connect to nearby towers or “cell sites” to receive service. Your cellular provider—and potentially law enforcement—can track your location by monitoring which cell site your phone connects to. Many smartphone apps also use GPS to pinpoint your exact whereabouts, as seen when Uber locates you for a ride.

In Carpenter v. United States (2018), the Supreme Court ruled that police generally need a warrant to obtain historical cell-site data from your provider. On Monday, April 27, the Court will hear Chatrie v. United States, a follow-up case that raises critical questions left unanswered by Carpenter:

• What should a warrant specify when police seek cellphone location data?
• How much location information should warrants allow police to collect?
• When can the government obtain data on innocent, uncharged individuals?
• Does voluntary use of location-tracking services, like Google Maps, affect privacy rights?
• Should tech companies turn over anonymized data, and when must they reveal a user’s identity?

The case highlights a broader issue: modern technology enables unprecedented government surveillance, far beyond what the Constitution’s framers could have imagined. The Supreme Court has spent decades adapting the Fourth Amendment—which protects against unreasonable searches—to keep pace with technological advances. As noted in Kyllo v. United States (2001), the goal is to preserve the same degree of privacy against government intrusion that existed when the Amendment was adopted.

Yet the Court’s commitment to this principle remains fragile. The Carpenter decision, which established warrant requirements for cell-site data, passed by a narrow 5-4 margin. Two justices in the majority, Ruth Bader Ginsburg and Stephen Breyer, have since left the Court. Breyer was replaced by Justice Ketanji Brown Jackson, whose stance on digital privacy remains untested.

The Supreme Court’s ruling in Chatrie v. United States could either strengthen privacy protections or expand law enforcement’s access to sensitive location data, reshaping digital surveillance for decades.