Updated: 9:12 p.m.

Senate Majority Leader Harry Reid (D-Nev.) finally ended weeks of mystery about his health care reform bill on Wednesday night, setting the stage for a historic debate that could begin this week if he can get an initial OK from all 60 members of the Democratic Conference.

At first blush, Reid scored a coup with his $849 billion bill, because Democrats said the Congressional Budget Office estimated that it would slash the deficit by a whopping $777 billion over the next 20 years while providing insurance for an additional 31 million Americans. The price tag is also less than the $900 billion President Barack Obama had called for and the $1.2 trillion cost of the House-passed version.

However, one Senate Democratic leadership staffer acknowledged that the cost estimate did not even represent an official preliminary score from the CBO but was a representation of “preliminary feedback— that Reid has gotten from the nonpartisan Congressional agency. The staffer said Reid expects an official number from the CBO later Wednesday night.

Reid had predicted Tuesday that people would be “impressed— by his effort, and most Democrats did end up giving him rave reviews.

“He was applauded. His staff was applauded,— said Senate Budget Chairman Kent Conrad (D-N.D.), a deficit hawk who said Reid did “an exceptionally good job.—

The more liberal Sen. John Kerry (D-Mass.) agreed that the measure appeared to address most of the concerns Senate Democrats had before Reid merged a Senate Finance package with a competing measure approved by the Senate Health, Education, Labor and Pensions Committee.

“Where there has been a difference [between the two panels], the leader chose the right difference,— Kerry said.

Kerry acknowledged, however, that Democrats would still be eager to change the bill even more if it survives a GOP-led filibuster designed to prevent debate from starting. He noted that the expansion of Medicaid would need to be tweaked to satisfy many Senators, including himself.

But before Reid briefed the Democratic Conference on the bill Wednesday evening, the Majority Leader attempted to get a head start in gaining the votes of a trio of troublesome Democrats who have yet to commit to that critical procedural vote to bring the bill to the floor.

Reid summoned Sens. Blanche Lincoln (Ark.), Ben Nelson (Neb.) and Mary Landrieu (La.) to a special preview of his bill earlier in the day, before the full Democratic Conference got to see it at 5 p.m. Though none was prepared to endorse the measure, Senate Democratic aides said Reid is increasingly confident he will have the votes necessary to begin debate on the bill. If the GOP-led filibuster is successful, the Senate will not be able to bring the measure up for debate and amendments.

Reid told reporters after the special caucus that “the finish line is really in sight,— and he called his bill “a tremendous step forward.—

Besides Reid’s optimism, there were other signs that he would ultimately get the three wavering centrists to come aboard despite their reservations about Reid’s decision to include a public insurance option that allows states to opt out.

In a statement that appeared to indicate he is leaning toward voting with Reid, Nelson said those who claim a vote for an arcane and routine procedural motion is akin to endorsing the bill are misleading people. Nelson, a moderate who insisted he is still undecided, said a vote to kill the GOP filibuster of the motion to proceed is just a vote to start debate, not a vote to pass the bill.

“Some who define it as a vote in favor of the Reid bill are misinformed, or are intentionally trying to mislead people. … And some who define it as the last chance to stop bad legislation have a political agenda: They want to kill any health care bill Congress considers this year for leverage in next year’s Congressional elections,— Nelson said.

Nelson said that the motion to proceed is simply a motion to commence debate and an opportunity to begin amending the bill.

“Why would you stop Senators from doing the job they’re elected to do — debate, consider amendments and take action on an issue affecting every American?—

Sen. Chris Dodd (D-Conn.) sounded hopeful that the other Democrats would come around. Dodd led the HELP Committee’s consideration of its health care overhaul last summer, filling in for the late Chairman Edward Kennedy (D-Mass.).

“These are serious people who in a couple of cases have worked on this for a long period of time. They are not outliers. … My sense is leave some space. They know all the questions, they know all the answers, let them settle on where they need to be in all of this.—

Dodd also said he believes that some form of public option will survive despite filibuster threats from Republicans and Sen. Joe Lieberman (ID-Conn.). The words “public option— are pretty flexible, Dodd suggested.

“Those words alone embrace an awful lot of thought and alternative ideas that would quote arguably qualify as a public option,— Dodd said. “Is it opt-out, is it opt-in, is it a trigger, is it a co-op? … I think before you decide I’m never going to be for that, I think you need to know what you are talking about.—

As of press time, it appeared that Reid would start the procedural clock ticking Thursday in order to hold the initial test vote on Saturday. However, aides said they held out hope that an agreement could be reached to hold the vote earlier. Reid is hoping to adjourn the chamber for the Thanksgiving recess this weekend, but he has kept open the possibility of keeping Senators in town next week to get debate rolling on the measure.

A Senate leadership aide said Reid’s overhaul bill would slash the deficit by $127 billion in the first decade and a stunning $650 billion in the second — numbers that would make the bill by far the best at closing the long-term budget gap of any bill produced to date in either chamber.

Reid told reporters: “We’re not going to add a dime to the deficit. In fact, quite the opposite. We’re going to cut the problems we have with money around here by as much as three-quarters of a trillion dollars.—

But another senior Senate Democratic aide noted that the large savings the initial bill would produce gives Reid substantial wiggle room to accommodate other policy objectives on the way to securing the 60 votes needed to break another expected filibuster on final passage of the bill.

Reid also attempted to assuage the concerns of organized labor, which had balked at the Senate plan to tax high-cost, or “Cadillac,— insurance plans by raising the limit on what kinds of plans would be taxed. He also included exceptions for workers in high-risk jobs, such as construction workers and police officers — many of whom are in unions.

To make up for the lost revenue, Reid also raised the threshold for taxing high-cost health care plans. He decided to include increased Medicare taxes on couples making more than $250,000, Conrad said.