During the wee hours, Democrats rounded up 60 votes to clear a crucial Republican procedural hurdle and put a broad revamp of the health care system on a path for passage on Christmas Eve.
"The Senate has moved us closer to reform that makes a tremendous difference for families, for seniors, for businesses, and for the country as a whole," said President Barack Obama.
The vote early Monday was the first test of whether Democrats could stick together to secure the 60 votes needed to overcome unified Republican opposition and muscle changes to the health care system through the Senate.
The health care overhaul, Obama's top legislative priority, faces two more procedural tests with a 60-vote threshold — on Tuesday morning and Wednesday afternoon — before a vote on final passage now scheduled for Thursday night.
"We'll get this passed before Christmas and it will be one of the best Christmas presents this Congress has ever given the American people," said Democratic Senator Tom Harkin.
The influential American Medical Association, the largest doctors' group with 250,000 members, endorsed the Senate legislation and said it would provide significant reform.
This bill advances many of our priority issues for achieving the vision of a health system that works for patients and physicians," AMA President-elect Cecil Wilson told reporters at a news conference with Democratic senators.