Much of the debate over phone surveillance in recent years has focused on the federal government and counterterrorism operations, particularly a once-secret program authorized by President George W. Bush after the Sept. 11 attacks. It allowed the National Security Agency to eavesdrop on phone calls of terrorism suspects and monitor huge amounts of phone and e-mail traffic without court-approved intelligence warrants.
Clashes over the program’s legality led Congress to broaden the government’s eavesdropping powers in 2008. As part of the law, the Bush administration insisted that phone companies helping in the program be given immunity against lawsuits.
Since then, the wide use of cell surveillance has seeped down to even small, rural police departments in investigations unrelated to national security.
“It’s become run of the mill,” said Catherine Crump, an A.C.L.U. lawyer who coordinated the group’s gathering of police records. “And the advances in technology are rapidly outpacing the state of the law.”