For all of Tuesday’s talk of Democrats reconciling with their wayward colleague, Sen. Joe Lieberman (ID), Senators said they will keep a close eye on the Connecticut Member’s party loyalty as he rejoins their caucus after his harsh criticism of President-elect Barack Obama’s candidacy.

“People will judge him as he goes forward,” Sen. Bob Casey (D-Pa.) said. “There’s no list of rules that he’s got to follow. He’s got to figure that out. I think people will be watching.”

Casey and other Senators said they would be particularly interested in Lieberman’s stewardship of the Homeland Security and Governmental Affairs Committee and how he handles overseeing an administration that he vigorously campaigned against as he stumped for his chosen presidential nominee, Republican Sen. John McCain (Ariz.).

“We’re all going to be paying close attention to that, as we would any kind of oversight,” Casey said. He acknowledged that it was a struggle for him to vote in favor of Lieberman keeping the Homeland Security gavel when Democrats decided Tuesday to let him retain that post while stripping him of his membership on the Environment and Public Works Committee.

The 42-13 vote in the Members-only meeting also effectively removed Lieberman as chairman of Environment and Public Works Subcommittee on Private Sector and Consumer Solutions to Global Warming and Wildlife Protection. He will continue to serve as chairman of the Armed Services Subcommittee on Airland.

Senators said Lieberman did not give many specifics about how he would run the Homeland Security Committee or how he would vote on a variety of issues. Sen. Chris Dodd (D-Conn.), who led the discussion in the Democratic Conference, said Lieberman raised the oversight issue by indicating that “he intends to do it very constructively and positively.”

One Democratic Senator said Lieberman’s promise to the caucus was not explicit, but he told them that they would “not regret” letting him remain at the helm of the full committee.

Even Senators who said they were satisfied that Lieberman would conduct committee business appropriately expressed some doubt.

“I do not believe that will be an issue,” Sen. Dianne Feinstein (D-Calif.) said. But, she added, “I could be wrong.”

Lieberman was vague with reporters when asked about his plans for the Homeland Security panel. “I think my colleagues voted overwhelmingly to go forward in a positive way, which is exactly the way that I intend to go forward,” he said.

Majority Leader Harry Reid (D-Nev.) declined to answer what he and the Democratic Conference now expected of Lieberman, saying he wanted to “move forward” with a broad new Democratic agenda in the 111th Congress.

Beyond concerns that Lieberman might use the Homeland Security panel for frivolous investigations of the Obama administration, Senators said letting Lieberman keep his full committee chairmanship as well as letting him remain in the Democratic Conference was conditioned on Lieberman’s renewed sense of loyalty to the party.

“That’s inherent in the offer that was made,” Sen. Frank Lautenberg (D-N.J.) said. “It was, ‘Welcome back. It’s not a partial welcome. These are the conditions under which you’re welcome back.’ We obviously expect his full support for the Democratic agenda.”

And they said they also are looking for signs that Lieberman is ready to be a full member of their caucus again, considering he stopped showing up at weekly Democratic policy lunches this year after breaking with the party on ending the Iraq War and on who should be president.

“I think it’s important for him to show that he’s a team player. I think he understands that,” Sen. Sheldon Whitehouse (D-R.I.) said.

Whitehouse and others said there was no specific criteria that they would be judging him on.

“I don’t think there’s a particular telltale,” Whitehouse said. “I think it’s kind of a sum and substance argument, but it was very important for the caucus today to send a message that we want to go forward as a unified caucus to put the past behind us and get serious about the process of governance. And so it’s pretty simply about him participating in a positive way in that process.”

Even Senators who spoke out against Lieberman during the closed-door meeting said they were trying to move on.

“I voted against the Lieberman resolution,” Sen. Bernie Sanders (I-Vt.) said. “I think it will be a disappointment to millions of people who worked very hard for Barack Obama, but now is the time to move on and start paying attention to the middle class and working families of this country.”

Democrats appeared to feel constrained by Obama, who made it known in post-election phone calls to Senators that he would rather forgive and forget Lieberman’s support for McCain. Still, many in the Democratic Conference have argued that the party could not condone Lieberman’s decision to criticize Obama as well as inject himself into Senate races on behalf of two incumbent Republicans.

That split appeared to be on full display Tuesday as Democrats attempted to both stress their desire for reconciliation, while also emphasizing — presumably for the benefit of left-wing bloggers who had sought Lieberman’s removal as Homeland Security chairman — that taking away Lieberman’s Environment panel assignment was indeed a stinging rebuke of his actions during the election.

“I think if it had been a resolution that had not had anything in it, it would not have been warmly received,” said Dodd, who helped broker the compromise that kept Lieberman from switching parties but exacted some retribution for his transgressions against the party. “There had to be some cost to this.”

From his position on Environment panel, Lieberman has been at the forefront of the debate on global warming, and he said Tuesday that that would not change just because he no longer serves on the panel. He said he gave up his seat on the panel at Reid’s request “in the spirit of cooperation.”

Senators and aides who were briefed on the meeting said Lieberman did apologize to his colleagues for the remarks that he made about Obama.

Speaking to reporters, Lieberman said, “I said very clearly … some of the things that people have said I said about Sen. Obama are simply not true. There are other statements that I made that I wish I had made more clearly. And there are some that I made that I wish I had not made at all, and obviously, in the heat of campaigns that happens to all of us. But I regret that and now it’s time to move on.”

When asked about his speech at the Republican National Convention in which he said Obama was a “young man” who spoke well and would be a good leader in the future, Lieberman did not indicate whether he apologized to his colleagues for those remarks.

“What I said at the convention was to explain why I was supporting Sen. McCain,” he said.

David M. Drucker contributed to this report.