Privacy experts say that a pair of new mobile privacy bills recently introduced in Texas are among the “most sweeping” ever seen. And they say the proposed legislation offers better protection than a related privacy bill introduced this week in Congress.

If passed, the new bills would establish a well-defined, probable-cause-driven warrant requirement for all location information. That's not just data from GPS, but potentially pen register, tap and trace, and tower location data as well. Such data would be disclosed to law enforcement "if there is probable cause to believe the records disclosing location information will provide evidence in a criminal investigation."

Further, the bills would require an annual transparency report from mobile carriers to the public and to the state government.

Under current federal case law and statute, law enforcement generally has broad warrantless powers to not only track suspects in real-time based on their phone data, but also to access records of where and when calls were made or text messages were sent or received—and all of this is provided by the carriers.

“Location information can reveal a great deal about an individual’s professional and personal life—her friends and associates, her participation in political or religious activities, her regular visits to a health clinic or support group, and more,” said Chris Conley, an attorney with the ACLU of Northern California.

“That’s why we think it is essential that the government get a search warrant, approved by a judge, before demanding this kind of information from cell phone providers. The Texas bill would require just that. In addition, the Texas bill would also require companies to report how often they receive such demands from law enforcement and how much information they disclose. This kind of transparency is essential to carry on an informed dialog about appropriate law enforcement powers in the modern world.”

Broad powers

The unanimous 2012 Supreme Court decision on United States v. Jones ruled that law enforcement did not have the authority to track a suspect using a GPS tracking device put on a car without a warrant. But cops frequently use similar tactics with lower legal standards, including using the suspect’s own phone against her. Last year, the American Civil Liberties Union sued the Department of Justice to release GPS tracking-related memos.

The bills, which were introduced in the Texas House of Representatives and the Texas Senate last month, are endorsed by the Texas Electronic Privacy Coalition. That's an umbrella group that includes the Electronic Frontier Foundation-Austin, Grits for Breakfast, Texans for Accountable Government, and the ACLU of Texas. They will need to pass both houses and be signed by the state governor, Rick Perry, before becoming law.

Ars reached out to the four major mobile carriers in the United States—AT&T, Verizon, Sprint, and T-Mobile—for their comment on this new bill. None of them responded on Wednesday except for Verizon, whose spokesperson, Debi Lewis, said the company had no comment.

One bill at a time

Not surprisingly, other civil libertarian and digital rights groups are looking with a hopeful eye that such legislation can influence other states and perhaps the federal government. According to the ACLU, 11 states have already introduced similar bills this year.

“What the states do on this issue will certainly influence what Congress does,” said Gregory Nojeim, senior counsel at the Center for Democracy and Technology. “It's clear to me that because the location of a cell phone is mobile and because phones cross state lines routinely it's probably that if the states start acting then Congress would need to enact a uniform rule.”

Various states have tried to implement versions of such privacy protections in the past. California’s was famously vetoed by the governor in September 2012. Sen. Al Franken (D-MN) introduced legislation in 2011 that would have also imposed similar restrictions, but none as strong as what’s been proposed in Texas.

“Although Senator Franken’s Location Privacy Protection Act of 2011 [PDF] and these Texas bills all seek to protect cell phone user’s location information, the Texas bills differ from Franken’s bill in scope, function, and specific objective,” Woodrow Hartzog, an affiliate scholar at Stanford Law School, told Ars. “Senator Franken’s bill is narrowly tailored to ensure that companies obtain consent before collecting or sharing location data from a consumer’s mobile device. The Texas bills are broadly aimed at the government’s collection of location information.”

He added that these bills were among the “most sweeping mobile location protection bills I've seen,” and he wondered if and to what degree they will become law.