Senate Democratic centrists believe the 111th Congress has given them the right ingredients to exercise considerable influence, but they still face an uphill battle in a chamber where such alliances typically fail.

Following its early success in paring down the more than $900 billion economic stimulus bill to $787 billion, a group of 15 to 20 Democratic moderates plans to formally announce next week that it is aligning as a loose coalition or working group focused on deficit reduction and fiscal responsibility. While not identical to the long-established House Democratic Blue Dog Coalition, the group is eyeing a similar role.

Led by Sens. Evan Bayh (D-Ind.), Tom Carper (D-Del.) and Blanche Lincoln (D-Ark.), members said early press reports of their meetings were mischaracterized as an opposition group to President Barack Obama’s agenda and budget. But they acknowledge that they are seeking to restrain the influence of party liberals in the White House and on Capitol Hill.

“We’re not a counterweight to anybody. We’re not here to obstruct anything. We’re here to help get to 60 votes,— Bayh said, referencing the threshold that’s needed to overcome filibusters.

Bayh said the group is made up of “pragmatists … not ideologues— and is intended to be “a forum to see if we have a consensus approach to getting things done.—

Carper said Members want to be a constructive partner with the White House and Democratic leaders to get important legislation like health care reform and climate change passed.

“The voters of this country have put their trust in the Democratic Party. They want us to govern,— Carper said. “That doesn’t mean they want us to govern too far to the left, just as they didn’t want the Republicans to govern too far to the right.—

Carper said the increased number of moderate Senate Democrats has made it more likely that the new group can succeed in tempering legislation and fostering bipartisanship. Plus, the Senators are better positioned to help the president reach out to Republicans on key issues, Carper said.

“There’s a need for building a bridge, and this is not a bridge to nowhere,— Carper said.

While centrists represented just a handful of seats in the 110th Congress, moderate Democrats saw their ranks swell in the 2008 elections as the party solidified its hold on Congress and took over White House.

At least six of the 11 new Democratic Senators have either attended a meeting or expressed interest in joining. Those six include Sens. Kay Hagan (N.C.), Jeanne Shaheen (N.H.), Mark Udall (Colo.), Mark Begich (Alaska), Michael Bennet (Colo.) and Mark Warner (Va.).

“The purpose of these groups is to get things done and move the ball forward on measures that will help get the economy back on track, while also developing a path for fiscal responsibility in the long term. When there’s an opportunity to influence legislation to better meet the needs of middle-class families, Sen. Shaheen will work with like-minded Senators to do so,— Shaheen spokesman Alex Reese said.

Democratic aides said the new moderate group could influence a whole host of legislation coming up, but that its most lasting influence this year could come on the budget resolution slated for action in the Senate later this month. The budget sets the party’s top line domestic spending numbers and sets priorities for legislation — including any health care reform, climate change bill or economic recovery measures.

But there are a few clouds on the horizon. Members already say they are not convinced that they will have the force of unanimity on every issue.

“It’s not monolithic, and not everybody is of the same mindset about everything within the budget. But there are going to be certain areas that I suspect people will band together on subject A or subject B,— said Sen. Ben Nelson (D-Neb.), who is a prominent member of the group.

Indeed, Nelson said the moderate bloc is modeled after the Blue Dogs, but that the realities of the Senate prevent them from being as organized or unified as the House group, which regularly wins concessions from House Democratic leaders.

“It’s not as orchestrated and organized as the Blue Dogs on the House side. This is a much more loosely knit group, but I think it’s a forum for discussion and for advocacy on issues. And that’s the purpose it’s going to serve,— Nelson said.

One Democratic Senator, speaking on the condition of anonymity, said any member of a Senate coalition that operates outside of the traditional caucus environment must tread carefully.

“Once you decide to be part of a bloc that is completely dislocated from the main caucus interests, you’ve not only separated yourself, you’ve also burned a lot of bridges,— the Senator said.

However, Bayh said he has kept Senate Democratic leaders fully informed of the group’s actions and even called White House Chief of Staff Rahm Emanuel after its first meeting last week. Emanuel was supportive of the group and asked to be invited to any press conference that would formally unveil the alliance, Bayh said.

Other Democrats said the history of centrist coalitions has been murky. Currently, there are two competing bipartisan moderate groups that at times have attendance problems and lack focus.

“There have been a lot of these groups in various incarnations over time, but they kind of fizzle out,— one senior Senate Democratic aide said.

The aide added that Blue Dogs have more of an incentive to coalesce as a group around specific positions than Senators do. In the Senate, one Member can influence legislation more readily than in the 435-Member House.

“It’s hard to retain a bloc of people when it comes to bills like spending bills because people are too easily picked off by having other local priorities taken care of,— another Senate Democratic aide said.

Indeed, the Senate centrists may be able to claim victory on the stimulus, but their resolve was never tested on a bill that most Democrats were loath to oppose.

More than a dozen Democratic moderates advised Nelson and Sen. Susan Collins (R-Maine) on the compromise package of cuts that the two offered to the stimulus. However, Reid and the White House intervened to help negotiate a deal that all Democrats could accept, and it never came to a floor fight.