Now that the House has passed major health-care legislation, the pressure is building on Majority Leader Harry Reid, D-Nev., to pass a bill by President Obama's Christmas deadline.
Reid has an even harder task in front of him than House Speaker Nancy Pelosi did. She barely pushed her bill over the threshold late Saturday night by a vote of 220 to 215, despite holding an 81-vote majority. Pelosi lost almost 15 percent of her members. If Reid loses one member of his 60-vote majority, his bill might be doomed.
But the White House is pushing hard for speedy passage of a robust plan to get President Obama's domestic agenda on track. Obama's Chief of Staff Rahm Emanuel reportedly paid Reid a visit last week after the majority leader sounded an ambivalent note about the president's holiday deadline.
Reid must contend with a group of more than a dozen moderate Democrats who are uncomfortable with or flat-out opposed to the creation of a new government health insurance program. Reid included such a provision in the Senate bill but said states could "opt out" of the program. Reid's bill also has penalties for individuals who don't purchase government-approved plans and businesses that don't offer coverage for employees.
Some health care policy experts are less sure.
Michael Cannon, a health care policy expert at the libertarian Cato Institute, said the razor-thin victory in the House will push the Senate bill farther right and cuts the clout of Senate liberals like Jay Rockefeller, D-W.Va., and Chuck Schumer, D-N.Y., who insisted Reid put a public option in the Senate bill.
"Moderate Senate Democrats are looking for more than just a three-vote margin in the House," Cannon said. "They are looking for more cover than that. If anything, the events of the past week will embolden moderate Democrats to buck their party."
Senate Democrats control 60 votes, including two Independents, exactly the number needed to overcome a procedural hurdle and bring a bill to the floor for consideration.
One of them, Sen. Joseph Lieberman, I-Conn., said he will vote against Reid's proposal, even if it costs him the chairmanship of the Senate Homeland Security Committee, though he is notorious for changing his mind at the last minute.
"I may be at a point in my career that I am going do what is right and makes sense," Lieberman said.
The 2010 elections complicate things further for the Senate. In the House, many of the 39 Democrats who voted against the bill are considered vulnerable in 2010. In the Senate, eight Senators face tough re-election battles, including Reid.
Tuesday's election results, in which Republicans won the governor's race in New Jersey and Virginia, sent a warning to Democrats, Republican National Committee Chairman Michael Steele said Sunday on ABC's "This Week."
"Pelosi can afford to lose 40 votes in the House, but Harry Reid cannot afford to lose one," Cannon pointed out.
Nothing will happen in the Senate until the Congressional Budget Office returns a cost analysis of Reid's proposal, which could happen this week.
At that point, behind-the-scenes negotiating for moderates' support will begin in earnest.