The documents, handed over by the government only after months of litigation, are the attorney general’s 2010 and 2011 reports on the use of “pen register” and “trap and trace” surveillance powers. ACLU

Pen register and trap and trace devices are powerfully invasive surveillance tools that were, twenty years ago, physical devices that attached to telephone lines in order to covertly record the incoming and outgoing numbers dialed. Today, no special equipment is required to record this information, as interception capabilities are built into phone companies’ call-routing hardware. ACLU

The reports show a dramatic increase in the use of these surveillance tools, which are used to gather information about telephone, email, and other Internet communications. ACLU

The Justice Department said it used “pen register” and “trap and trace” techniques 23,535 times in 2009 and 37,616 times in 2011. The Hill

The ACLU said the documents show that more people were subjected to pen register and trap-and-trace surveillance in the past two years than in the entire previous decade. The Hill

"It shouldn’t take a FOIA lawsuit by the ACLU to force the disclosure of these valuable reports. There is nothing stopping Congress from releasing these reports, and doing so routinely," wrote Naomi Gilens of the ACLU's Speech, Privacy and Technology Project. The Hill

She noted that the reports only cover the Justice Department, and not other federal agencies or local police. The Hill

"As a result, the reports likely reveal only a small portion of the use of this surveillance power," she wrote. The Hill

Former President George W. Bush signed a presidential order in 2002 allowing the National Security Agency (NSA) to monitor without a warrant the international (and sometimes domestic) telephone calls and e-mail messages of hundreds or thousands of citizens and legal residents inside the United States.

The program eventually came to include some purely internal controls -- but no requirement that warrants be obtained from the Foreign Intelligence Surveillance Court as the 4th Amendment to the Constitution and the foreign intelligence surveillance laws require.

In other words, no independent review or judicial oversight. ACLU

Two American senators with access to top-secret intelligence raised the alarm in May 2011, suggesting that the invasion of law-abiding Americans' privacy was being carried out clandestinely - and that people would be shocked if they knew the extent.

“I want to deliver a warning this afternoon,” Senator Ron Wyden said on May during a Senate debate. “When the American people find out how their government has secretly interpreted the Patriot Act, they will be stunned and they will be angry.” Al-Jazeera