Last year, police departments across the US linked up with wireless providers like Verizon and T-Mobile to pull the cellphone records of 1.3 million Americans. They harvested a bundle of of data — things like text messages and emails, personal contacts, and call histories — all in the name of solving crimes. But here's the catch: all the data phone companies handed over was obtained without a warrant, and without the approval of a judge.

A new bill by Massachusetts Congressman Ed Markey would rein in this practice. The Wireless Surveillance Act of 2012 compels law enforcement to prove probable cause before learning who you've called and where you've been spending your time.


Kade Crockford, project manager and principal investigator of the Technology for Liberty Project at the ACLU of Massachusetts.