The government can track you on your cellphone. Doesn’t that invade digital privacy?

Erwin Chemerinsky writes for The Sacramento Bee, Dec. 11, 2017

Every federal court of appeals to consider the issue has held that no warrant is required before police access cellular location information. These courts have relied on a legal principle called the “third party doctrine” – that we have no privacy interest in information that we share with a third party, such as a phone company.