WASHINGTON – The House voted to renew a modified USA Patriot Act to combat terrorism on Wednesday and sent the bill to the Senate, where opponents pledged a last-ditch fight against provisions they said would curtail individual liberties.

The vote in the House was 251-174, with 44 Democrats joining 207 Republicans. “Renewing the Patriot Act before it expires in December is literally a matter of life and death,” said Rep. Ric Keller, a Republican of Florida.

Across the Capitol, though, a possible Democratic-led filibuster awaited. GOP aides expressed uncertainty that supporters could muster the 60 votes needed to prevail, and one senior Republican aide said Senate Majority Leader Frist had held discussions with the White House on a fallback plan that would extend the law for one year unchanged.

Dr. Frist issued a statement saying, “I am opposed to a short-term extension.”

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 the war on terror, we cannot afford to be without this law for a single moment.”

Congress overwhelmingly passed the Patriot Act after the September 11, 2001, terrorist attacks. The law expanded the government’s surveillance and prosecutorial powers against suspected terrorists, their associates and financiers.

Republicans said the country will be left vulnerable if the Patriot Act is not renewed.

But the bill’s opponents say the original act was rushed into law, and Congress should take more time now to make sure the rights of innocent Americans are safeguarded before making 14 of the 16 expiring provisions permanent.