WASHINGTON — Centrists in the Senate are celebrating their work to reopen the government after a three-day shutdown. They hope to build on their momentum to address a host of issues beyond immigration, including health care and disaster relief.

About 20 moderate senators met in the office of Maine Republican Sen. Susan Collins over several days and helped broker an agreement to pass a stopgap spending measure keeping the government open until Feb. 8.

Now the senators say they want to leverage that goodwill and return the Senate to its historic role as a deliberative body that produces bipartisan legislation. Despite their optimism, lawmakers face the weight of heavy expectations and the knowledge that past attempts to forge centrist solutions on immigration and other thorny issues have been thwarted by the vocal bases of both parties.

Senators have dubbed the informal group the Common Sense Caucus, but “hopefully it’ll grow large enough that we’ll eventually call it the United States Senate,” said Sen. Angus King of Maine, an independent who is one of the group’s informal leaders.

King has been here before. Five years ago, he was part of a similar but smaller group that worked to end a 2013 government shutdown. That group dissipated after the government reopened, but King and others say the new effort has a chance to stick around.

Sen. Jeff Flake, R-Ariz., returns to the Capitol after working with a bipartisan group of moderate senators, including Sen. Angus King, I-Maine, right, to find a way to reopen the government, in Washington on Sunday.

“I think what’s different is a number of us have said, ‘Let’s keep this going. Let’s not make this a shutdown-only event,”‘ King said in an interview. “Let’s talk about some things we can do to improve how this place works.”

If they can stay united, the group could be a crucial voting bloc in the closely divided Senate, King and other senators said.

“I think everybody’s looking for that middle,” said Sen. Joe Manchin, D-W.Va. “Everybody has input. Everybody trusts everybody in that room.”

Success in the Senate is far from guaranteed. Movement in the Republican-controlled House – where the 2013 immigration bill died without a vote – is even less certain, but senators said they are forging ahead.

“For the first time, we at least have some hope,” said Sen. Bill Nelson, D-Fla. “And that’s because you’ve got a bipartisan group of senators that want to get something done.”

Sen. Lisa Murkowski, R-Alaska, sees the group as a “safe space” where lawmakers can exchange ideas, regardless of party.

“I hope we can kind of be an incubator of good ideas – common sense ideas,” she said. “Our job is to keep government working.”

The three-day shutdown ended with new assurances from Senate Majority Leader Mitch McConnell, R-Ky., that the Senate would consider immigration proposals in the coming weeks.

From left, Sen. Jeff Flake, R-Ariz., Sen. Chris Coons, D-Del., Sen. Amy Klobuchar, D-Minn., and Sen. Jeanne Shaheen, D-N.H., arrive at the Capitol after a bipartisan group of moderate senators held a private meeting in Washington on Sunday. Sen. Angus King, I-Maine, is at rear.

“We now have a window of opportunity to show we can work together and build a bipartisan consensus that produces a product worthy of time on the (Senate) floor,” said Sen. Chris Coons, D-Del., one of the leaders of the bipartisan group.

In language repeated by other senators, Coons said the shutdown crisis provides an opening to “let the Senate be the Senate” and allow free-flowing debate on immigration and other issues.

The concept does not extend to the House or President Donald Trump’s White House – both of which are likely to be formidable obstacles on immigration – but those problems can be addressed later, Coons and other senators said.

“If President Trump would let the Senate be the Senate and work for the next three weeks, I think he’d be encouraged and surprised at how positive the results could be,” Coons said.

Sen. Jeff Flake, R-Ariz. was equally upbeat.

Flake, who has been pushing a bipartisan immigration solution for months, said he is optimistic that the spirit of cooperation born in Collins’ office – dubbed Little Switzerland by senators – will extend to the debate on immigration and beyond.

“It will be nice to see a process on the Senate floor that we haven’t seen in a long time,” since a comprehensive immigration bill was approved in 2013, Flake said. “We went through regular order and dealt with amendments and everybody had their say. This will be much like that.”

Until now, a solution on immigration has been held back in part by uncertainty over what Trump will accept, Flake said. While lawmakers still are not sure what Trump wants on immigration, they are moving forward anyway.

“I hope the president will say, ‘Here’s what we need,’ but if not, we’ll pass something and see if the president likes it,” Flake said.