Senate Democratic centrists aren’t saying “yes” just yet, but when it comes to passing a crucial piece of the health care reform puzzle, party leaders have reason to be optimistic that enough of their most fickle Members will put them over the top.

With few exceptions, Democratic moderates interviewed Wednesday revealed little resistance to the idea of using controversial budget reconciliation rules to clear the final health care reform package and deliver it to the president’s desk. Given their strong opposition to embracing this strategy when health care was being debated last year, their fresh openness could prove significant even if some moderates ultimately vote “no.”

“There are plenty of people in our caucus who would like to not vote for reconciliation, but my guess is 51 is something [leadership] can get,” said one Democratic Senator of the simple-majority vote needed for passage. “This is like a box canyon, and reconciliation is the only way out.”

Majority Leader Harry Reid’s (D-Nev.) repeated urgings for centrists to hold their fire on reconciliation has clearly paid off; it has allowed moderates to keep their votes flexible as the party weathered the loss of its supermajority on Jan. 19 when Sen. Scott Brown (R-Mass.) was elected.

Reid, Speaker Nancy Pelosi (D-Calif.) and President Barack Obama have known for more than a month that they were likely going to have to use reconciliation to get health care over the final legislative hump. But just recently the trio officially settled on a strategy that would require the House to approve the $871 billion Senate-passed bill and both chambers to pass a reconciliation measure that addresses House complaints about the Senate measure. Reid can afford to lose eight to nine Democrats and still pass the bill, perhaps with the vote of Vice President Joseph Biden, who serves as President of the Senate and can vote if there is a tie in the chamber.

[IMGCAP(1)]Of course, the same centrist Democrats who drove such a hard bargain over health care reform last year were clear they would not sign off on legislation absent an understanding of what policies would be included in the reconciliation vehicle. But they were careful to not rule it out either.

“I wouldn’t say it’s only because of the leader’s suggestions,” Sen. Mary Landrieu (D-La.) said of why she has kept an open mind. “I think that instinctively we know that these negotiations are still going on, you know, informally between the House and the Senate. … I think people are just waiting to see, you know, what happens.”

Like other Democratic moderates, Landrieu is only OK with reconciliation now because the bulk of the health care reform agenda was already approved under the original Senate bill that needed 60 votes to pass.

“What I said from the beginning is I would be opposed to passing and crafting a bill through reconciliation. But this bill was not crafted or passed through reconciliation, it was passed with 60 votes in the United States Senate,” Landrieu said.

Though it is clearly a good sign for Reid that centrists are open to voting for reconciliation, many of those Members aren’t quite ready to sign a letter pledging their support for a bill, aides said. Pelosi may demand such a letter as proof positive that the Senate has enough support to pass the bill.

“People might make a private commitment to leadership but wouldn’t sign a letter,” one senior Senate Democratic aide said.

Indeed, some Senators fear that by signing a letter they could be lambasted by conservatives and other groups for weeks before voting. The attacks would only increase for those lawmakers if the controversial process falls apart and a vote never takes place.

Senators and aides have noted this week that no decision has been made on whether a letter will be necessary.

Even strong supporters of Obama’s agenda made clear they need to know what they’re voting for before they sign off on a 51-vote strategy.

“I can’t say reconciliation is OK until I know what’s in it,” said Sen. Claire McCaskill (D-Mo.), an ally of the president. Obama this week is set to visit St. Louis as he seeks to build support for his health care initiative. One aim of this latest version of health care reform outlined by Obama is to eliminate provisions that were inserted into the original $871 billion Senate package to make a “yes” vote more palatable to skeptical moderates.

Sen. Ben Nelson’s (D-Neb.) much-maligned “Cornhusker kickback,” which he secured in the Senate bill to cover the cost of a proposed Medicaid expansion for his state, is likely to be expanded to include a reimbursement for all states. But Nelson cautioned that will not guarantee his vote for any reconciliation measure. Still, Nelson noted he has voted in the past for reconciliation bills and may again.

Liberal stalwart Sen. Jay Rockefeller (D-W.Va.) said centrists should not be nervous about the reconciliation piece considering it “does not affect 98 percent of the health care bill. If [the House] passes the Senate bill, that’s the health care bill. [Reconciliation] is just those few things they would add on to make the House happier.”

But Sen. Joe Lieberman (ID-Conn.), a problematic vote for Reid during last year’s debate, did not agree that reconciliation was a minor bill, saying that passage of the Senate bill and a reconciliation measure are inextricable.

Reconciliation “effectively will enable the bill to be enacted. … So I think it’s a mistake to do something this big through reconciliation.”

But like his fellow moderates in the Democratic Conference, Lieberman will not commit himself either way. “Why am I undecided? Because one, I don’t like reconciliation for something this big. It ought to go through the regular order and get 60 votes,” Lieberman said. “But on the other side, there’s a lot of good things in the Senate-passed bill.”

Last year, Lieberman was accused on multiple occasions of backing out of agreements he made with Reid on the Senate bill. Still, Lieberman said he has not yet been consulted on the language of any potential reconciliation bill.

Only Sens. Blanche Lincoln (D-Ark.) and Evan Bayh (D-Ind.) have said they would oppose a reconciliation bill because of their objection to the process. Lincoln, facing a tough re-election bid this year, reaffirmed her opposition Wednesday.

However, fellow Arkansas Democratic Sen. Mark Pryor said he would not necessarily be bound to vote the same way as Lincoln. But he noted of reconciliation, “I’m not real crazy about the idea, but let me just wait and see.”

Reconciliation is a special Senate procedure designed for budget-related bills that among other things prohibits filibusters, allowing legislation to clear the chamber with only 51 votes. The tool has been used nearly two dozen times since its creation in the 1970s, including by Congresses of both parties.

The Senate passed its bill on a party-line vote on Christmas Eve last year, and House approval is all that is needed to send it to the president. The reconciliation measure is intended to be a substitute for the House-Senate conference report, which Senate Democrats no longer have a 60-vote majority to pass.