By Tim Starks, CQ Staff

The House was nearing a vote on an electronic surveillance overhaul after a contentious day that featured the first secret session of the House in 25 years and furious efforts by Democratic leaders to round up caucus support for their plan.

Before the late-night secret session began Thursday, a number of the 21 conservative “Blue Dog” Democrats who had endorsed a competing Senate bill (HR 3773) and whose votes are crucial to the new House legislation’s fate appeared to be lining up behind Democratic leaders.

Ultimately, though, even the bill’s passage Friday would not resolve anytime soon what has been a grinding legislative slog for Democrats wrestling with a long-lasting overhaul of the Foreign Intelligence Surveillance Act (FISA, PL 95-511).

President Bush has vowed to veto the new House bill, giving it virtually no chance of passing in the Senate, although Senate Majority Whip Richard J. Durbin , D-Ill., said Thursday that the chamber intends to take it up after the spring recess.

The biggest dispute is that the Senate bill would — as Bush has sought and congressional Republicans have insisted upon — grant retroactive legal immunity to telecommunications companies being sued for their alleged cooperation with the National Security Agency’s warrantless surveillance program. The House bill, in an attempt to address some of the companies’ concerns without granting them full immunity, would instead give them an avenue to present to judges classified material they view as necessary to their legal defense, but which is currently closed off by the Bush administration.

The latest turn in the debate came Thursday, when Republicans opposed to the new bill requested, and Democrats agreed to, a secret session of the House.

Minority Leader John A. Boehner , R-Ohio, said the session would allow an “open and honest debate about some of the important details about this program that don’t need to be heard in public.”

Pelosi agreed to the request. “We’re having debate on the bill. And I don’t have any problem with having part of it in closed session and part of it in open session,” she said.

Many Democrats were skeptical, however, of accomplishing much in the secret session, and they accused Republicans of stalling for political purposes.

House Intelligence Chairman Silvestre Reyes , D-Texas, said only a small number of lawmakers are privy to details of the president’s warrantless surveillance program, so those details could not be discussed in the secret session.

Anyone who was going to be in the chamber during the discussion had to sign an oath of secrecy. Members who violate the oath would be subject to disciplinary action, up to expulsion; chamber officers or employees who divulge secrets could be fired.

A record of the proceedings would not be made public unless the House votes to do so. If it doesn’t, a transcript would be sent to the National Archives and could be made public only after 30 years.

The session only began after a number of liberal Democrats who had opposed a unanimous consent agreement relented. Dennis J. Kucinich , D-Ohio, questioned the need for a closed session to deal with FISA legislation, saying the House should debate legislation in public, but then made clear he would not try to block the session. “We ought to proceed with the utmost caution in going in this direction. . . . I believe that it violates the spirit of this House,” he said.

But Democrats had other internal disputes to settle before they could move a bill through the House. A number of conservative Democrats who favored the Senate legislation had to be persuaded to support the new bill.

Reyes said, “We’ve worked this pretty hard,” and aides and lawmakers reported intense vote whipping throughout the day. At various points, aides and lawmakers doubted the bill could pass, but grew more confident as the day went on. Democrats would only need a handful of the 21 Blue Dogs — barring any other defections — to win passage of the bill.

One Blue Dog who said Thursday — after days of review — that he was leaning toward supporting the new House bill was Leonard L. Boswell of Iowa. Boswell engineered a January letter to Pelosi backing the Senate legislation.

He said the House bill “would allow classified information to go to a judge, not the prosecutor or plaintiff. It’s my opinion, in that setting, the telecoms are OK and their needs are met. If that’s what comes up, I’m prepared to stand up and support it.”

Republicans and the administration, however, have maintained that only retroactive immunity will ensure future cooperation from the companies.

Some of the other 21 Democrats who signed Boswell’s letter and who now say they are leaning toward supporting the new House bill include Mike Ross of Arkansas and John Tanner of Tennessee. Both said they supported the legislation because it increases the chances of an eventual resolution to the FISA debate, even though they still prefer the Senate bill.

Others were experiencing pressure from the opposite direction. Jim Cooper of Tennessee said he had not yet made up his mind on the legislation, but that he’d had conversations throughout the day with a number of officials, including the director of national intelligence, Michael McConnell .

Some lawmakers, including Cooper, said they wanted to hear what was said in the secret session before making a final decision.

It was only the fourth such House session since 1830.

The last time either chamber met in secret was a Nov. 1, 2005, Senate session to discuss efforts to speed an oversight investigation of the Bush administration’s handling of Iraq intelligence. The last closed House session was July 19, 1983, to discuss U.S. support for rebels in Nicaragua.

The House was scheduled to debate a rule to strip the Senate-passed legislation and insert the new legislation into it Friday, then move to a full debate and vote on the bill.

Alan K. Ota, Molly Hooper and Josh Rogin contributed to this story.