Police shouldn’t be able to get your sensitive location data – information that can reveal your religion, health, hobbies, and politics – on a whim. That’s why EFF and the ACLU of Northern California are sponsoring California Senate Bill 1434, the Location Privacy Act, which would ensure law enforcement obtains a warrant before acquiring a person’s location information from an electronic device like a cell phone.

SB 1434, introduced by California Senator Mark Leno, follows the lead of the U.S. Supreme Court, which recently ruled that it was unconstitutional for police to install a GPS device on someone’s car without a warrant. But GPS vehicle tracking isn’t the only way to collect details on where you are and when. Our cell phones create a location data trail throughout the day as they ping nearby cell towers.  Many other devices – like tablets – do the same, while mobile apps and other tools can collect even more detailed location information.

This data is a powerful tool for law enforcement, and should be available to police when it’s appropriate. But this information is extraordinarily sensitive, revealing things like your place of worship, if you are visiting a medical clinic, and who you visit and meet with.  We can’t have police making decisions about who to track without any oversight – yet that’s exactly what’s happening.  New data from the ACLU shows that law enforcement agencies across the country are collecting location data without a warrant or any court approval. Maybe these investigations are legitimate, or maybe in some cases police officers just have a bone to pick with a local resident. We can’t be sure that police aren’t abusing location tracking unless we require them to get a warrant. That’s why the bill also includes a reporting requirement, so we can keep track of who is getting this information and how often it’s being requested.

The law passed through both houses of the California legislature with broad bipartisan support, but was unfortunately vetoed by Governor Jerry Brown in October 2012.