The House voted 251-174 to approve a House-Senate compromise that would modify and make permanent most of the Patriot Act's 16 expiring provisions.
But despite intense lobbying from the Bush administration, the measure could be in trouble in the Senate, where a filibuster is threatened, supported by at least a few Republicans, who say the FBI's new post 9/11 powers need to be reined in.
President Bush urged against any delay in Senate action. "The Patriot Act is essential to fighting the war on terror and preventing our enemies from striking America again," he said in a statement. "In the war on terror, we cannot afford to be without this law for a single moment."
Facing a threatened filibuster, Senate Majority Leader Bill Frist, R-Tenn., was talking with White House officials about a one-year extension of the current law without any changes, a senior Republican aide said.
Frist's action indicated new trouble for making most of the 2001 law's provisions permanent, a priority for both the Bush administration and Republican leaders on Capitol Hill before Congress adjourns for the year.
Congress overwhelmingly passed the Patriot Act after the Sept. 11, 2001, terrorist attacks. The law expanded the government's surveillance and prosecutorial powers against suspected terrorists, their associates and financiers.
Republicans say the country will be left vulnerable if the Patriot Act is not renewed.
"Renewing the Patriot Act before it expires in December is literally a matter of life and death," said Rep. Ric Keller, R-Fla.
But the bill's opponents say the original Patriot Act was rushed into law, and Congress should take more time now to make sure that the rights of innocent Americans are safeguarded before making 14 of the 16 expiring provisions permanent.
They are pushing a temporary extension of the law so they can lobby for additional safeguards in the law. "If we enact the bill as written, a little bit of the liberty tree will have died," said Rep. James McGovern, D-Mass.
While the bill's opponents did not have enough votes in the House, a group of Republican and Democratic senators is banding together in the Senate to block the House-Senate compromise.
Senate vote-counters trying to tally support and opposition for an agreement that would revise the 2001 anti-terror law were unable to precisely gauge its prospects Wednesday.
If the agreement to renew the act fails a crucial test of support, Frist was preparing to bring up his own legislation to extend the current Patriot Act for a year, according to a senior Frist aide who spoke on condition of anonymity because the decision had not yet been made.
That would mark a victory for lawmakers of both parties who were lining up against the compromise.
They argued that the House-Senate accord would allow government too much power to investigate people's private transactions. Congress needs more time to add privacy protections, these lawmakers say.