Most of the Patriot Act, which expanded the government's surveillance and prosecutorial powers against suspected terrorists, their associates and financiers, was made permanent when Congress overwhelmingly passed it after the Sept. 11 terrorist attacks on New York City and Washington.
The Senate, with only Sen. John Warner of Virginia present, gave final approval to the new Feb. 3 expiration date Thursday night four hours after the House, also with a near-empty chamber, bowed to Rep. James Sensenbrenner's refusal to agree to a six-month extension the Senate had cleared Wednesday.
Congress can pass legislation with only a few lawmakers present as long as no member of the House or Senate objects. The Senate session lasted four minutes.
Sensenbrenner, chairman of the House Judiciary Committee, said the shorter extension would force swifter Senate action and had the support of the Bush White House and Speaker Dennis Hastert. The Senate reconvenes Jan. 18, and the House returns Jan. 26.
"A six-month extension, in my opinion, would have simply allowed the Senate to duck the issue until the last week in June," the Wisconsin Republican told reporters.
Most Senate Democrats and a few libertarian-leaning Republicans united against a House-Senate compromise that would have renewed several expiring provisions permanently while extending some others for another four years.
Democrats were pleased with a short-term extension, whether for six months or just a few weeks.
"The amount of time is less important than the good-faith effort that will be needed in improving the Patriot Act to strike the right balance in respecting Americans liberty and privacy, while protecting their security," said Sen. Patrick Leahy, D-Vt., the ranking Democrat on the Judiciary Committee.
"We're happy to agree to a shorter-term extension of the Patriot Act," said Rebecca Kirszner, an aide to Senate Minority Leader Harry Reid. "The important thing is to strike the right balance between liberty and security."
House passage marked the latest step in a stalemate that first pitted Republicans against Democrats in the Senate, then turned into an intramural GOP dispute.
Without action by Congress, several provisions enacted in the days following the 2001 terror attacks are due to expire. Mr. Bush has repeatedly urged Congress not to let that happen.
The Senate vote Wednesday night marked a turnabout for GOP leaders, who had long insisted they would accept nothing less than a permanent renewal of the law. The House approved the measure earlier this month, but a Democratic-led filibuster blocked passage in the Senate, with critics arguing the bill would shortchange the civil liberties of innocent Americans.