Sen. Joe Lieberman (ID-Conn.) returned to the Senate this week as an outsider, and the independent-minded lawmaker says he is comfortable with his status in the Senate and among his colleagues.

Lieberman’s situation is unsettled because of the displeasure he has caused within the Democratic caucus for his decision to not only back GOP presidential hopeful Sen. John McCain (Ariz.), but also to be a vocal critic of Democratic candidate Sen. Barack Obama (Ill.).

In a brief interview Tuesday, Lieberman said he’s OK with his new lot among Senate Democrats and has no regrets about his speech for McCain at last week’s Republican nominating convention. The one-time Democratic vice presidential candidate said he was “at peace” with his decision to back his friend McCain, regardless of the personal consequences next year.

“Really, I am doing what I think is right, and what I think is best for the country,” Lieberman said. “It’s important Sen. McCain win the election for the presidency at this time.”

He added that his post as chairman of the Homeland Security and Governmental Affairs Committee “is less important than that,” adding that he will “let the rest take care of itself.”

Lieberman’s awkward standing in the Democratic caucus is not new, given he endorsed McCain’s candidacy last December and has been a regular presence on the presidential campaign trail. Still, his speech at the GOP convention secured him a new loneliness in the halls of the Senate where he is no longer an active participant in Democratic meetings nor is he a welcome member of the GOP Conference.

Lieberman and Majority Leader Harry Reid (D-Nev.) have agreed that for the remainder of the election cycle, Lieberman will not attend any of the Democratic caucus lunches, policy lunches or biweekly chairmen’s lunches because sensitive campaign issues will be discussed. The deal is an expansion of Lieberman’s voluntary decision to not attend caucus lunches where the Iraq War — which has been at the core of his break with Democrats — was discussed. With campaign issues dominating lawmakers’ discussions, top Democratic lawmakers and aides said the practical effect of the deal is that Lieberman will not be attending any meetings until after the election.

Reid attempted Tuesday to downplay the arrangement.

Lieberman has been “invited to everything we’ve done,” including the weekly meeting of Democratic chairmen and the weekly caucus meetings. … If he chooses not to attend those, that’s his decision, not ours,” Reid said. “We’re going to have an election on Nov. 4, and unless something changes, things will remain as they are.”

But privately, Democratic aides acknowledged that Reid and Lieberman have discussed the issue and that while Lieberman was not forced out, he will not be attending party meetings at least until after the election.

Democratic leaders have reason to walk a fine line with Lieberman. Although highly unlikely, Democrats worry he could decide to cut ties with Democrats and caucus with Republicans — which could turn the chamber over to Minority Leader Mitch McConnell (R-Ky.) for the remainder of the session.

But those close to Lieberman rejected this scenario, saying the lawmaker is not one to act out of vengeance.

Lieberman also still has close friends in the Senate, not the least of whom is Reid, who has long defended his colleague and has chosen his words carefully when asked about his standing in the next Congress. Reid also was among the last to walk away from Lieberman two years ago when he lost his primary election as a Democrat and had to run as an Independent to secure another six-year Senate term.

Sources familiar with discussions between the two lawmakers said that before the political conventions last month, Lieberman informed Reid that he would speak, although the substance of his remarks was not discussed.

In his first week back from the convention, Lieberman’s legislative director, Joe Goffman, announced his resignation Monday. Although Goffman gave no reason for his departure, Democratic aides familiar with his decision said once work was completed on Lieberman’s climate change bill, combined with Lieberman’s convention speech, Goffman felt that it was time to move on.

Colleagues also are increasingly unhappy with Lieberman for attacking Obama.

Sen. Byron Dorgan (D-N.D.) said he was “very disappointed” in Lieberman’s performance at the convention, adding that the remarks “went way beyond what I would even expect him to do.” But Dorgan insisted that any decisions about Lieberman’s future will “be deferred until after the election.”

“Joe is a friend,” Dorgan said. “The fact that I am very disappointed doesn’t mean we aren’t friends. A decision about what this all means will be put off for another day.”

Other Democratic leaders — including Speaker Nancy Pelosi (Calif.) and Democratic vice presidential candidate Sen. Joseph Biden (Del.) — have also criticized Lieberman, and have gone so far as to warn that he could lose his chairmanship once the election is over.

Homeland Security and Governmental Affairs ranking member Susan Collins (R-Maine) — a Lieberman ally — said she was surprised at Democrats’ reactions. Collins noted that Reid’s leadership of the Senate hinges on Lieberman’s decision to continue caucusing with Democrats even after the 2006 elections, when he switched party affiliations.

“But for Sen. Lieberman’s caucusing with Democrats, none of them would be chairman,” Collins said, adding that, “I think they’ve pushed that very salient fact out of their minds.”

Emily Pierce contributed to this report.