"The only way to get this done before Christmas is to bring in some Republicans who are open-minded on this like Olympia Snowe (of Maine)," Lieberman said. To do that, he said that among other things, "You got to take out the Medicare buy-in. You got to forget about the public option."
Last week, it appeared Senate Democrats had worked out a plan to get past divisive issues, like the so-called public option, and were on their way to 60 votes for reform. That plan includes a proposal to allow people ages 55 to 64 to buy into Medicare, the popular government plan that serves senior citizens.
Lieberman, however -- one of the Democratic caucus members the plan was intended to appease -- said on "Face the Nation" he would not vote for a bill that expands Medicare.
"From what I hear, I certainly would have a hard time voting for it because it has some of the same infirmities that the public option did," he said.
(Read more about the status of the Senate health care debate at CBSNews.com's Health Care Progress Report.)
Sen. Ben Nelson (D-Neb.), another conservative who may or may not vote for the health care bill, also said on "Face the Nation" that the Medicare buy-in is "the forerunner of single-payer, the ultimate single-payer plan, maybe even more directly than the public option."
While it's not just Lieberman expressing reservations about the Medicare buy-in, the prominent senator reportedly took his complaints directly to Senate Majority Leader Harry Reid (D-Nev.), saying he plans to vote against any bill that expands Medicare.
Lieberman is also bearing the brunt of criticism from the left: "Looks like Joe Lieberman decided to try for the old double-cross and say he now opposes the Medicare expansion compromise he'd hinted he would support," writes Matthew Yglesias of Think Progress, a project of Center for American Progress Action Fund that advances progressive ideas.
Washington Post blogger Ezra Klein writes, "At this point, Lieberman seems primarily motivated by torturing liberals. That is to say, he seems willing to cause the deaths of hundreds of thousands of people in order to settle an old electoral score." Klein points to a study revealing how many people die because they are uninsured.
Meanwhile, Jane Hamsher, founder of liberal blog network FireDogLake is blasting the Susan G. Komen for the Cure, an organization that supports breast cancer research, for retaining Lieberman's wife, Hadassah Lieberman, as its "Global Ambassador."
Firedoglake launched a petition and sent a formal letter to the group requesting they part ways with Hadassah Lieberman for two reasons: Mrs. Lieberman is a former health insurance lobbyist, Hamsher writes, and her husband Joe Lieberman is "an instrument of obstruction to the kind of health care reform advocated by Susan G. Komen for the Cure."