Senator Ron Wyden (D-OR) has brought a bill that would require police to get a warrant before pulling location data from phones or GPS devices. Wyden, along with Representative Jason Chaffetz (R-UT) and Mark Kirk (R-IL), are reintroducing the Geolocation Privacy and Surveillance or GPS Act after a first attempt in 2011 failed to make progress. The ACLU has found that police departments routinely used location information in investigations, and previous court cases have upheld their right to get phone GPS data without a warrant under current laws. But the idea that law enforcement has easy access to an always-on tracking device hasn't sat well with many people.

In 2012, the rules on placing actual bugs to track suspects became stricter: the Supreme Court ruled in US v. Jones that putting the device on a car without a warrant constituted an unreasonable search. The ruling, however, didn't address whether collecting information through a third party like a phone carrier was legal. Wyden's bill would change that, explicitly covering either real-time or archived location data collected by companies. Wyden says the procedures for getting a warrant would be much like those for wiretapping — and like wiretapping, there would be an exemption for national security interests.

Wyden isn't the only one with a bill to ban warrantless tracking. Earlier this month, Representative Zoe Lofgren (D-CA) and others introduced the Online Communications and Geolocation Privacy Act, which would extend Fourth Amendment protections to online communications and location data.