WHERE THINGS STAND…. Monday was obviously a big day for health care reform, with Senate Majority Leader Harry Reid (D-Nev.) announcing that he’s moving forward with a bill that includes a public option with a state opt-out compromise. Tuesday was nearly as big a day — senators got a chance to respond to what they heard on Monday.

The White House, you’ll recall, expressed some skepticism about proceeding with Reid’s plan, not because the president and his team disagreed with it on the merits, but because they did not see a scenario in which it could get 60 votes for cloture. There are 58 Democrats, 40 Republicans, and two independents in the Senate. Getting to 60 means no room for error — with no GOP votes, Democratic leaders can’t spare a single member of the caucus.

And yesterday, center-right Senate Dems did exactly what the White House feared they might do.

Senate Democrats voiced deep disagreements on Tuesday over the idea of a government-run health insurance plan, suggesting that the decision by the majority leader, Harry Reid of Nevada, to include a public plan in major health care legislation had failed, at least initially, to unite his caucus.

Simply to get the Senate to take up the legislation, Mr. Reid has said he needs 60 votes — effectively all 58 Democrats and the two independents who caucus with them. Senator Olympia J. Snowe, Republican of Maine, who had been open to supporting the bill, said Tuesday that she would oppose Mr. Reid’s version because of the public plan.

But while some who oppose a public plan said they were willing to let Mr. Reid bring the legislation to the floor, the continuing apprehension of others indicated substantial uncertainty.

Joe Lieberman, as you may have noticed, is not only opposed to a bill with a public option, but announced yesterday he’s prepared to join with Republicans in blocking a vote on reform. He was not, however, the only trouble-maker: Sens. Ben Nelson (D-Neb.), Evan Bayh (D-Ind.), Mary Landrieu (D-La.), and Arkansas’ Blanche Lincoln and Mark Pryor all said, at a minimum, they were not prepared to endorse the legislation.

For her part, Sen. Olympia Snowe (R-Maine) not only said she opposes Reid’s proposal, but would even vote to block the Senate from considering the bill at all (i.e., the motion to proceed). At this point, though, even the center-right Dems are unlikely to join the GOP on this, and will vote to send the bill to the floor to begin the debate and amendment process.

For what it’s worth, yesterday was annoying, but not altogether unexpected. Roll Call reported that Reid’s office was largely unfazed by yesterday’s developments: “The Majority Leader is taking the long view, and he appears unconcerned by the early opposition from Democratic moderates, although he is not dismissing it. According to a senior Democratic Senate aide, Reid understands that some centrists might be playing to a home-state crowd, while others are looking for bargaining power as the final bill takes shape.”

Indeed, one of the more striking observations of the day was that most of the Hill still seems convinced that health care reform will pass — in one form or another — in the near future. The NYT added, “With or without a public plan, Democrats expressed growing confidence that a version of the health care bill would be adopted.”

As for the House, the search for 218 remains challenging, but the leadership is reportedly making progress, and still expects to begin debate on a bill as early as next week.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.