California had its chance, but now Montana has become the first state in the U.S. to require that police obtain a search warrant before using a person’s cellphone records to track their whereabouts.

The new law mandates that law enforcement have probable cause before asking a judge for a warrant that permits the examination of metadata collected by telecommunications companies.

Police can ignore the law if the cellphone is reported stolen or if they are responding to an emergency call from the user.

Lawmakers in California adopted a similar law last year, but Democratic Governor Jerry Brown vetoed it, saying it did not “strike the right balance” between the needs of citizens and law enforcement.

Other states have also considered the legislation. In Maine, a location information privacy bill now awaits approval from the governor. Texas legislators rejected the idea, in spite of recently passing a bill that made its state the first in the nation to require a warrant for email surveillance. Massachusetts lawmakers plan to conduct a hearing on a measure that would require search warrants for location records as well as content of cellphone communications.

Federal legislation—the Geolocational Privacy & Surveillance Act (pdf)—was recently introduced in Congress, but neither the House nor the Senate has taken it seriously so far.

-Noel Brinkerhoff

To Learn More:

With Montana’s Lead, States May Demand Warrants for Cellphone Data (by Somini Sengupta, New York Times)

First in the Nation: Montana Requires a Warrant for Location Tracking (by Allie Bohm, American Civil Liberties Union)

House Bill No. 603 (Montana Legislature)

Texas First State to Require Warrants for Email Surveillance (by Noel Brinkerhoff and Danny Biederman, AllGov)

FBI Uses Portable Device to Track Cell Phone Users (by Matt Bewig, AllGov)     

Appeals Court Rules Justice Dept. Must Reveal Details of Warrantless Tracking of Cell Phones (by Noel Brinkerhoff, AllGov)