Updated

A key piece of legislation the Bush administration is seeking to help fight the war on terror is on hold for now in the face of stiff opposition to a provision that would grant telecommunication companies immunity from pending lawsuits.

Senate Majority Leader Harry Reid pulled the update to the Foreign Intelligence Surveillance Act off the chamber floor late Monday in the face of heavy opposition from powerful members of his own party, which controls the Senate by a slim majority.

"We have tried to work through this process, and it appears quite clear at this stage on this bill that we're not going to be able to do that. ... Hopefully, when we come back after the first of the year, we can figure out a way to move through this," Reid, D-Nev., said on the Senate floor Monday night.

Congress passed a short-term fix to FISA in August, which has been criticized by some Democrats for what they said gave the Bush administration too much leeway to track down terrorists. But the bill set a Feb. 1 expiration.

But the most controversial provision — the telecom immunity provision — is related to the administration's terror surveillance program to track terrorists at home and abroad. Also called the domestic surveillance program, some companies like AT&T and Verizon complied with administration requests for phone numbers in its pursuit of leads. Those companies now face up about 40 lawsuits for privacy invasion and other matters.

President Bush supports the bill in its current form — with the immunity provision intact. But the president has threatened to veto the bill if Congress sends it to him without the immunity provision.

The Senate agreed, 76-10, on Monday to start debate on the bill — crafted by the Intelligence committee's top Democrat, Chairman Jay Rockefeller of West Virginia, and Ranking Republican Kit Bond of Missouri. The bill would be a permanent update to the 1978 Foreign Intelligence Surveillance Act.

But some key Democrats sought to use the immunity provision as a weapon against the president and Republican supporters in the Senate.

"The president has threatened veto. ... He's willing to let Americans die to protect the phone companies!" said Sen. Edward Kennedy, D-Mass.

Sen. Ron Wyden, D-Ore., who sits on the Select Committee on Intelligence, said the administration's case for immunity is thin. Members of the intelligence and judiciary committees have been permitted to see a set of the classified documents that lay out the administration's legal opinions on immunity and its information requests to companies.

"I have read the documents and senators who haven't read them would be shocked to see how flimsy the case is on which the administration bases its case for immunity," said Wyden, who is prevented from discussing the details of the documents because they are classified. "As far as I can tell, these documents are being kept secret to protect the president's political security, not national security."

Sen. Chris Dodd of Connecticut, a 2008 presidential candidate, returned to Washington Sunday night from the campaign trail in Iowa to fight the immunity provision, and accused the administration of being "overly secretive" and "constantly seeking to protect itself" from speaking with reporters.

Dodd didn't hesitate in bringing presidential politics into the fray either, challenging fellow candidates Sens. Hillary Clinton, Barack Obama and Joe Biden to join him in fighting the provision.

Dodd began launching an old-fashioned filibuster to win support for his amendment to strip out the immunity provision, actually trying to halt the current version of the bill by speaking until colleagues give in.

Usually filibusters end quickly when senators merely indicate they will not support a bill in the preliminary cloture vote, killing the bill before it goes to final vote. Dodd's spokesman had expressed the senator's willingness to hold the floor even if it meant reading from the Iowa phone book.

On Monday, the senator spent seven hours on the floor, mounting an informal filibuster. Senate Majority Leader Harry Reid of Nevada tried to get Dodd to agree to a 60-vote threshold for all amendments to FISA, but Dodd refused.

Dodd says granting immunity to the telecoms could open the door to letting the administration peer further into Americans' private lives.

"If I can reach in and listen to your phone conversations, why not grant immunity to someone who'd like to know what your medical records or your financial records are under the same argument that's being made here today? ... Where do you stop?" Dodd asked.

The protest gums up the works procedurally. Reid would have to push a series of procedural provisions to shut Dodd down, but the schedule might not allow for that, that is even if Reid wanted to do so, which is not known at this time.

"Senator Reid hopes to try and finish the FISA bill this week," Reid spokesman Jim Manley said in a likewarm statement to FOX News. Manley said Reid is still working on a strategy for finishing up the week.

The bill has strong support on the Republican side of the aisle, which has been unified enough with its 49 votes to stymie Democratic efforts

"It was an easy thing for 13 members of the Senate Select Committee on Intelligence to vote to grant retroactive immunity to companies that patriotically adhere to legal letters, to provide the names by whereby we might be able to protect citizens in this country, and perhaps all over the world," said Sen. Orrin Hatch, R-Utah, who also sits on the intelligence panel.

"Because of that work, we have been able to protect this country in ways that most people will never know," Hatch said, calling the lawsuits against the telecoms "dubious," and a threat to national security because they seek to reveal classified information.

The White House threatened Monday to veto any bill that does not contain a retroactive immunity provision. The Senate Intelligence Committee's version of the bill provides it; a competing version from the Judiciary Committee does not. The House-passed version also does not provide retroactive immunity.

Multiple efforts were under way Monday to craft alternative immunity provisions. Among the potential amendments is one by Sen. Arlen Specter, R-Pa., who wants the U.S. government to stand in for telecommunications companies as the defendant in the cases. The Senate Judiciary Committee declined to put such a provision in its version of the bill. Sen. Dianne Feinstein, D-Calif., also was working on an immunity amendment.

The Bush administration has requested a permanent rewrite of FISA to enable the intelligence community to catch up with advances in telecommunications technology that have made the law nearly obsolete.

FISA requires the government to obtain court approval before conducting electronic surveillance on U.S. soil, even if the target is a foreign citizen in a foreign country. Many purely international communications are now routed through fiber-optic cables and computers in the U.S., which would not be exempted under the old law.

The White House wants authority to monitor foreign communications involving Americans without first getting court approval, as long as the American is not the intended target of surveillance.

One senior Senate GOP leadership aide said he thinks the delaying tactics were planned by Democrats all along.

"Milk it for a little political gain on telecom immunity, then come back and push our backs up against the wall before PAA expires," the aide said. On the other hand, if the Senate doesn't finish action on the issue, it could allow the telecom immunity provision time to cool in the political arena, giving it a fresh start after the first of the year.

The new surveillance bill must be passed before Feb. 1 if the the government is to keep its authority to listen in on American communications without court permission.

FOX News' Trish Turner and The Associated Press contributed to this report.