Sen. Joe Lieberman (ID-Conn.) is unlikely to face retribution if he votes to filibuster the Democratic health care bill, despite renewed calls from outraged liberals for party leaders to punish him by stripping him of his committee chairmanship.

Majority Leader Harry Reid (D-Nev.) “needs his vote,— one senior Senate Democratic aide said. “It would be counterproductive.—

Several aides and Senators indicated that the Conference had already dealt with Lieberman’s perceived disloyalty to the party last fall, when Democrats voted to let him keep the gavel of the Homeland Security and Governmental Affairs Committee despite his aggressive campaigning for then-GOP presidential nominee Sen. John McCain (Ariz.). Lieberman did, however, lose his slot on the Environment and Public Works Committee — a sanction that stung given his long-standing work on global warming legislation.

“If you’re not going to punish someone for endorsing the Republican candidate for president, when are you going to punish him?— another Senate Democratic aide asked. “I don’t even know if this is a punishable offense.—

The aide added that Lieberman has at least committed to voting down a filibuster intended to prevent the health care bill from even being debated on the Senate floor, whereas other Democratic moderates, such as Sens. Ben Nelson (Neb.), Blanche Lincoln (Ark.) and Mary Landrieu (La.), have made no such commitments.

Lieberman has said he would vote to block a final vote on the bill if it contains any type of public insurance option, including a “trigger.— Reid’s proposal calls for a public option with an opt-out for individual states.

Sen. Tom Carper (D-Del.), who helped Lieberman keep his chairmanship last year, said he spoke to Reid about Lieberman recently.

“I talked with our leader about Sen. Lieberman’s role in all of this. Part of it was respect for [Lieberman’s] views,— Carper said. “And the fact that he’s willing to vote to bring to the floor for debate and amendment legislation that he does not fully agree with, I think, is very constructive.—

And Carper said he believes there is a compromise that could be offered on the floor that might garner Lieberman’s support.

“At the end of the day, can we find a way to give states lots of options, including a plan that could be adopted in … many of the states in a way that is not government-controlled, is not government-funded? I think we can do that,— Carper said. “If we can, then he votes — I hope — with all of us and maybe a few Republicans to report the bill.—

[IMGCAP(1)]Lieberman’s home-state colleague and a central player in the Senate health care debate, Democratic Sen. Chris Dodd, agreed that there may be something that Lieberman can get behind: “People are making more of this than is the case. We agree on a lot of things; we disagree on some things. [Health care] is a big issue, but I think, when we get a public option, there may be a public option that Joe will support. I’m not worried about it.—

Despite the threat to block his party’s No. 1 domestic priority and his consistent support for Republican war policies, Lieberman has been a fairly reliable vote for Senate Democrats, even after he lost his primary bid in 2006 and won re-election as a self-described Independent Democrat. While he was campaigning for McCain in 2008, Lieberman voted with the majority of Democrats 81 percent of the time, according to the latest vote studies by Congressional Quarterly.

Plus, Lieberman has proved a valuable asset this year. One Lieberman aide noted that the Senator answered the call to duty during this year’s economic stimulus debate — before Democrats had a 60-vote majority and needed at least two Republicans to vote with them. Lieberman, a close friend of Maine Republican Sen. Susan Collins, used his relationship with her to act as a conduit for Reid, sources said.

“Reid’s approach to Lieberman is not to be punitive, and that has paid some dividends,— another senior Senate Democratic aide said.

The Lieberman aide noted that Reid and Lieberman may not be personally close, but they consider each other friends and have a good working relationship — a factor that may contribute to Reid’s reluctance to bend to liberal demands for revenge.

“With Sen. Reid and Sen. Lieberman, they have such an open relationship they’ll talk out their differences or explain their differences to each other,— the aide said. “From Sen. Lieberman’s perspective, they trust each other. There’s a transparency in their relationship.—

But the Lieberman aide shot down a report Tuesday that Lieberman and Reid have brokered a private deal for the Connecticut Senator to eventually support any Democratic health care bill.

“If you believe this story is true, you will also believe that I am replacing A-Rod in Game Six of the [World] Series,— the aide said. “The suggestion … that Sen. Lieberman has made a ‘private understanding’ on his votes on health care reform is absolutely not true. Sen. Lieberman’s clear position is that he will vote for the motion to proceed to the health care bill because he supports health care reform that will control costs and insure people who don’t have it now, but will oppose cloture on a final bill if it contains a public option.—

Reid spokesman Jim Manley said Lieberman is still a valuable member of the Democratic Conference.

“A great majority of the time, Sen. Lieberman votes with his caucus,— Manley said. “This may be one time they disagree.—

Still, Manley did not completely rule out the possibility that Lieberman could face another vote of confidence from the Democratic Conference when Senators vote on leadership positions and chairmen after next year’s election.

“The only thing Sen. Reid is focused on right now is to try to get the vote for a good strong bill,— Manley said. “These kinds of decisions will be left to the caucus at the end of next year.—