Early on the morning of Christmas Eve, the Senate passed its health reform legislation, voting 60-39 (Republican Sen. Jim Bunning of Kentucky was absent) on reforms that have been so hotly debated for the entire year.

At times, it seemed that health reform was doomed to fail--that the Democratic coalition that supported it wouldn't hold, and that nothing would pass--but it did. It now seems clear that President Obama will sign some form of health care package early next year.

Two questions remain now that Democrats have succeeded in moving forward. They are: 1) How much will the bill change in the House/Senate conference committee, which will convene in early January when both houses of Congress come back into session? and 2) How happy or unhappy will liberals be with whatever passes in the end?

As for the first, it's unlikely that drastic changes will be made during conference. The Senate has always been the limiting factor of political will on health care: as far as moderate Democratic senators are willing to go is about as far as health reform can go.

But nearly every major liberal interest or activist group has pledged to press for something better out of conference. There will be intense pressure on the White House and Senate Democratic leaders from a significant segment of President Obama's base--a segment that helped him get elected in 2008 with hundreds of millions in campaign spending--to get something more aggressive to his desk.

Unless the political winds shift, and Sen. Joe Lieberman (I-CT) has a change of heart as to what he's willing to support, major concessions are unlikely to be won. There is still the lingering possibility that his vote could be traded for Sen. Olympia Snowe's (R-ME): if liberals decide they'd be better off with a more robust expansion off government care with a trigger attached, as Snowe indicated she'd be willing to support, House negotiators could try to push things in a direction that could earn her vote.

As for the second question, the first round of liberal reactions to the Senate vote were mixed, and it appears all eyes are on the conference committee.

Health Care for American Now!, the massive interest group coalition that has backed Obama's reform push from the start, praised the Senate for moving the nation "one big step closer to comprehensive health care reform" but pledged to "urge President Obama to work with leaders in both houses of Congress to agree on legislation that meets [its] goals."

Service Employees International Union Andy Stern lavished praise on the Senate for its "historic" vote but, similarly, turned his focus to the next step: "Now, the Senate, the House and the White House have an opportunity to deliver real reform, worthy of every Americans support. To reach that point, to make sure the President is able to sign the best bill possible, we must fight to strengthen health insurance reform by taking the strongest provisions from both bills," Stern said.

AFL-CIO President Richard Trumka, meanwhile, called the Senate bill "inadequate." While praising the Senate for moving forward, he asserted that "[a]t this historic moment, it is so important to the future of working Americans--and to our country--to get health care reform right.  Despite doing some good things, the Senate bill remains inadequate.  Substantial changes must be made in the final bill."

From the early round of reactions, it's clear that liberals will want something more aggressive to come out of the conference committee, though it's still unclear how they'll respond if that doesn't happen, or if only a few concessions are won.