When two senators warned that the Patriot Act is being interpreted in a secret way that would alarm Americans if they knew the details, civil liberties activists could only speculate about what they meant.
The activists' fear: that the government is using the anti-terrorism law to collect vast troves of personal information, including cellphone records, on Americans who have no link to terrorism.
Congress voted overwhelmingly last week to reauthorize key provisions of the Patriot Act for four more years. President Obama signed it from France by authorizing the use of an autopen.
The Senate debate on the law featured an unusual dissent by two senators who serve on the Intelligence Committee.
Sens. Ron Wyden of Oregon and Mark Udall of Colorado, both Democrats, proclaimed that the Patriot Act's surveillance powers are being used far more expansively than most Americans realize. But they can't disclose what they know, they said, because the documents that detail how theObama administration implements the act are classified. As members of the Intelligence Committee, Wyden and Udall are privy to secret briefings.
"Today the American people do not know how their government interprets the language of the Patriot Act," Wyden said. "Someday they are going to find out, and a lot of them are going to be stunned. Some of them will undoubtedly ask their senators: 'Did you know what this law actually did? Why didn't you know? Wasn't it your job to know, before you voted on it?' "
In an interview, Udall said he wasn't even allowed to discuss details about the government's intelligence-gathering with fellow senators unless they go to a secure room in the Capitol designed to thwart eavesdropping.
But in a statement before the vote, Udall said the law allows the government to "place wide-ranging wiretaps on Americans without even identifying the target or location of such surveillance; target individuals who have no connection to terrorist organizations, and collect business records on law-abiding Americans, without any connection to terrorism."
Nonetheless, most members of Congress, including others who have received the classified briefings, apparently did not share their concerns. The Senate passed the extension, 72-23, with Wyden and Udall voting "no." The bill cleared the House, 250-153.
Still, the warnings by two lawmakers with access to secret information underscore the extent to which government surveillance is shielded from view, in an age when nearly every American leaves a digital trail through the Internet and mobile devices.
Civil libertarians say they suspect the act is used to justify bulk collection of data, most of which is associated with people unconnected to terrorism investigations. The business records provision, Section 215, is subject to a particularly broad reading, they say. It lets government obtain "any tangible things," including cellphone or other personal records, that are "relevant" to a terrorism inquiry after a secret order is obtained from the Foreign Intelligence Surveillance Court.
"There's absolutely nothing in the law that would prevent them from using 215 to do bulk grabs of stored information," said Michelle Richardson, an American Civil Liberties Union lobbyist.
Kevin Bankston, senior staff attorney with the Electronic Frontier Foundation, said, "I expect that the main concern is that they are obtaining cellphone records in bulk masses, often pertaining to people who have no link to spying or terrorism."
A clue about Wyden's concerns may be found in a separate bill he is proposing, to forbid the government from tracking, without a court order, the location of Americans through the GPS signals given out by their cellphones.
In 2009, members of Congress voiced concerns that the National Security Agency, which sweeps up huge volumes of foreign communications data, was "over-collecting" and obtaining phone and email records of Americans without warrants. No full accounting was ever made public.
Government officials declined to address the specifics of what Wyden and Udall were referencing. But Todd Hinnen, the assistant attorney general for national security, told Congress in March that the Patriot Act's business records provision supports "important and highly sensitive intelligence-collection operations" that he could not discuss further.
Dean Boyd, a Justice Department spokesman, noted that the surveillance is approved by the intelligence surveillance court.
"We have gone to great lengths to ensure that the public's elected representatives are fully informed of the ways in which we interpret and use these authorities," he said.
Wyden argued that it's one thing to support a provision about which the public is unaware, and another to have to explain it to constituents when they learn of its implications.
"I don't take a back seat to anybody when it comes to the importance of protecting genuinely sensitive sources and collection methods," he said. "But the law itself should never be secret -- voters have a need and a right to know what the law says, and what their government thinks the text of the law means."