At the same time, Congress and the White House were rushing to enact legislation to prevent a lapse in several of the federal government’s investigative powers under the Patriot Act that were set to expire at midnight. The Senate passed the bill 72 to 23 late in the afternoon, and within hours the House approved it 250 to 153. In an unusual move, a White House spokesman said that President Obama, who was in Europe, would “direct the use” of an autopen machine to sign the bill into law without delay.
During the debate, Senator Ron Wyden, an Oregon Democrat and a member of the Intelligence Committee, said that the executive branch had come up with a secret legal theory about what it could collect under a provision of the Patriot Act that did not seem to dovetail with a plain reading of the text. “I want to deliver a warning this afternoon: When the American people find out how their government has secretly interpreted the Patriot Act, they will be stunned and they will be angry,” Mr. Wyden said. He invoked the public’s reaction to the illegal domestic spying that came to light in the mid-1970s, the Iran-contra affair, and the Bush administration’s program of surveillance without warrants.
Another member of the Intelligence Committee, Senator Mark Udall, Democrat of Colorado, backed Mr. Wyden’s account, saying, “Americans would be alarmed if they knew how this law is being carried out.”
The Obama administration declined to explain what the senators were talking about. Dean Boyd, a Justice Department spokesman, said that Congressional oversight committees and a special panel of national security judges — known as the FISA Court — were aware of how the executive branch was interpreting and using surveillance laws.
“These authorities are also subject to extensive oversight from the FISA Court, from Congress, from the executive branch,” Mr. Boyd said.
Mr. Wyden has long denounced the idea of “secret law” — classified memorandums and rulings about the meaning of surveillance law developed by executive branch officials and the FISA Court. He and Mr. Udall had proposed requiring the Justice Department to make public its official interpretation of what the Patriot Act means. The chairwoman of the Intelligence Committee, Dianne Feinstein, Democrat of California, agreed to hold a hearing on their concerns next month.
The two had also sponsored a proposal to tighten the circumstances in which one of the expiring provisions, known as Section 215, could be used. It allows the F.B.I. to obtain “any tangible things” — like business records about customers.
Mr. Udall criticized Section 215, saying it lets the government get private information about people without a link to a terrorism or espionage inquiry.
In a 2009 debate over the Patriot Act, another member of the Intelligence Committee, Russell Feingold, Democrat of Wisconsin, also hinted that Section 215 was being used in a secret way that, he said, “Congress and the American people deserve to know” about. He was defeated for re-election in 2010.
The business records section of the Patriot Act had been set to expire, along with provisions allowing the F.B.I. to obtain “roving” wiretap orders to follow suspects who change phone numbers, and to obtain national security wiretaps against noncitizen terrorism suspects who are not connected to any foreign power.
Congressional leaders had agreed to extend the provisions before they expired. But Senator Rand Paul, a libertarian-leaning Republican from Kentucky, initially blocked an expedited vote on the bill because he wanted Senate leaders to allow a vote on several amendments. The Senate majority leader, Harry Reid, Democrat of Nevada, allowed votes on two Paul amendments, which would have offered greater privacy protections for records involving gun sales and banking.