Police searches of mobile phone data have skyrocketed during President Barack Obama's time in office, roughly doubling in just the last five years, the American Civil Liberties Union (ACLU) reported Monday.

Between just three of the nation's largest carriers -- AT&T, Verizon and T-Mobile -- over 870,000 police requests for mobile phone data were documented in 2012 alone, according to letters the companies sent to Senator Edward Markey recently.

Requests for information, including the location of individual mobile phones, voice mails and text messages, have surged thanks in part to an outdated law governing how law enforcement may go about accessing that data. The Electronic Communications Privacy Act (ECPA) -- passed in 1986, well before email, text messages and GPS were common -- is frequently cited by advocacy groups like the ACLU because it allows law enforcement to obtain communications older than 180 days without requesting a warrant.

"Our mobile devices quite literally store our most intimate thoughts as well as the details of our personal lives," ACLU legislative counsel Chris Calabrese said in an advisory. "The idea that police can obtain such a rich treasure trove of data about any one of us without appropriate judicial oversight should send shivers down our spines."

The ACLU, along with the Electronic Privacy Information Center (EPIC), the Electronic Frontier Foundation (EFF) and the Center for Democracy and Technology (CDT) have been pushing lawmakers in recent months to update and reform the ECPA.

"The time has come for ECPA to be reformed to provide strong privacy protections while ensuring that law enforcement agencies can obtain the information they need to fight crime," a statement from CDT explains. "The best way to do that is to ensure that government agents must get a warrant from a judge before tracking our movements or reading our private communications."

The ACLU and the CDT in particular recently joined forces with Heritage Action for America and Americans for Tax Reform to create a group called Digital 4th, specifically designed to push for greater recognition of the Fourth Amendment in the electronic age. The Fourth Amendment was created to prohibit unreasonable searches and seizures by authorities.

"Our goal is to simplify, clarify, and unify ECPA's standards, providing stronger privacy protections for communications in response to changes in technology," the group says on its website. "Digital 4th at the same time supports preserving the legal tools necessary for government agencies to enforce laws, respond to emergency circumstances and protect the public."

"There is an easy fix to part of this problem," ACLU's Calabrese added. "President Obama and members of Congress should pass legislation that updates our outdated privacy laws by requiring law enforcement to get a probable cause warrant before service providers disclose the contents of our electronic communications to the government. Anything less is unnecessarily invasive and un-American."

Photo: Flickr user Ron Bennetts, creative commons licensed.