For Sen. Joe Lieberman (ID), there was never a question about whether he would support fellow Connecticut Sen. Chris Dodd (D) for re-election in 2010.

“I told Sen. Dodd I’d do anything I could to help him,— Lieberman recently told Roll Call. “He’s a wonderful public servant and deserves to be re-elected, and I’m going to help him.—

Lieberman’s endorsement comes as Dodd faces what is certain to be the toughest re-election of his nearly 30-year Senate career, as public polls have showed him trailing his likely Republican opponent. While his unequivocal support for Dodd is not surprising, Lieberman’s endorsement is also construed as a shrewd political calculation to get back in the good graces of Democrats in the Senate and voters in his home state.

“It’s part of Joe’s comeback as far as with the Democrats, there’s no question about that,— said John Droney, a former Connecticut Democratic Party chairman. “But even if it didn’t help him with Democrats, he would do it. That’s just the kind of guy Joe is.—

Until recently, Lieberman has always been the one in the political hot seat — from his support for the war in Iraq to his endorsement of Sen. John McCain (R-Ariz.) in the 2008 presidential race.

But this time, Dodd is the one in electoral peril. His quixotic 2008 bid for president, leadership of the Banking, Housing and Urban Affairs Committee during a national financial crisis and a well-publicized sweetheart deal on his home mortgage have put him in jeopardy heading into next year’s election. Polls have showed him trailing former Rep. Rob Simmons (R), earning Dodd the dubious honor of being the most vulnerable Democratic Senator up for re-election in 2010.

[IMGCAP(1)]Droney said Lieberman’s support for Dodd will help him with many moderate Democrats in the state.

“I think this Dodd thing is a big first step of coming back home,— added Droney, who supported Lieberman in his 2006 race but has worked for both Senators.

For Lieberman, this could also be a chance to return the favor. Most recently, Dodd lobbied Democratic leaders to allow Lieberman to retain his Homeland Security and Governmental Affairs gavel for this Congress, despite campaigning for McCain last fall.

“Dodd was an important advocate for Lieberman and that counted for a lot, both in terms of the impact it had within the caucus and in terms of their relationship,— said a source close to Lieberman, who declined to speak on the record.

And that wasn’t the first time Dodd had gone to bat for Lieberman: He pushed for Lieberman to be on the presidential ticket in 2000 and campaigned for him during his losing bid in a high-profile 2006 Democratic primary.

However, Lieberman lost the primary and then filed to run as an Independent. Dodd and other party leaders backed Democratic nominee Ned Lamont in the general election, and Lieberman acknowledged that his relationship with Dodd was rocked by that race.

“There was a personal rough patch during my 2006 election, but we’re over that,— he said. “We have too much history together and have worked together too long. We’re patched up; we’re friends.—

But while Lieberman may be back in the good graces of his fellow Connecticut Senator, many of his colleagues believe he has a long way to go before he could run again as a Democrat in the state in 2012.

“From afar, it may look like this helps him with Democrats in Connecticut,— the Lieberman aide said. “But the ill will is so far deep with Democrats in Connecticut, this is minimal.—

The head of the Connecticut AFL-CIO, John Olsen, said Lieberman’s relations with the Democratic base in the state are still strained, mostly because of his support for McCain last year.

“There’s a lot of anger from some party people who felt that from the standpoint of Connecticut, he had a popularity and he had a very negative impact on the country,— Olsen said.

A former state party chairman, Olsen supported Lieberman throughout his entire 2006 re-election bid. He said that compared to Lieberman, his organization holds Dodd in a higher regard.

“Obviously they’re much stronger in their support of Sen. Dodd than Sen. Lieberman,— he said, referring to the AFL-CIO.

Other Democrats in the state claim it’s “past the point of no return— for Lieberman and his party — and the feeling is likely mutual.

According to one longtime Connecticut Democrat, Lieberman is making a “shrewd— move by campaigning for Dodd: He can be a good Democrat by supporting his vulnerable colleague up for re-election, but still remain the key swing vote without irritating Senate Democratic leadership.

“I think it’s a shrewd, shrewd inside game, where this is an easy way to show that he’s, at this point in his career, is aligned with the Democrats,— said a longtime Connecticut Democrat who declined to be named. “It re-establishes his Democratic bona fides.—

Not surprisingly, Lieberman has had notably good relationships with some Republicans in Connecticut, including former Rep. Christopher Shays, his longtime friend who lost re-election in November after serving 10 terms.

While Lieberman and Simmons are collegial and friendly, the two are not personally close.

“Sen. Lieberman and I have worked productively together for many, many years, but I also know that Sen. Lieberman made an extraordinarily courageous choice to support John McCain for president,— Simmons said. “And that has created some problems for him in his caucus, and I would fully expect him to do anything he can do to re-establish himself in his caucus.—

Simmons said he met with Lieberman on a recent trip to Washington, D.C., but that an endorsement was not discussed. After all, Simmons said, Lieberman is still a Democrat.

“My guess is that here in Connecticut, he has some issues with his own party,— Simmons said. “He didn’t get their nomination. Some years and a careful reading of the polls suggest he may not get their nomination again, even if he comes out strongly in support of Chris Dodd.—

Jessica Brady contributed to this report.