Barack Obama's historic plan to overhaul the US health care system that the president says will provide health insurance coverage to the overwhelming majority of Americans was to be put to vote Sunday in the US House of Representatives.
The vote comes after a year of tough debate, months of setbacks, bitter partisanship, and legislative logjams -- and a dramatic week of chasing votes, led by Obama himself.
The president led Democrats in a triumphant, fist-pumping rally Saturday and confidently predicted Congress would rise to a century-old challenge and pass his health care overhaul.
"It is in your hands, it is time to pass health care reform for America, and I am confident that you are going to do it tomorrow," he told his allies. "Let's get this done."
The proposed overhaul, a compromise between rival House and Senate versions of the bill passed late last year, would bring the United States closer than ever to guaranteeing health care coverage to all of its citizens.
Using a blend of expanded government health programs and subsidies for millions to buy private insurance, the bill would add some 32 million Americans to the ranks of those covered for a total of 95 percent of Americans.
It would come a century after president Theodore Roosevelt called for a national approach to US health care.
As Obama spoke, thousands of protestors outside the Capitol chanted "Kill The Bill" and waved signs branding the president and his proposal "socialist" and lawmakers "corrupt", cheered on by the Republican minority.
With passions heating up, Democratic Representative Emmanuel Cleaver was spat upon, while gay Congressman Barney Frank and black Representative John Lewis were subjected to sexual and racist abuse, said House Democratic Majority Leader Steny Hoyer.
He denounced the incidents as "hateful."
To lawmakers worried that the broadly unpopular proposal could carry a political price in November mid-term elections, Obama said supporting the legislation was a correct thing to do.
"I know there is a tough vote," the president said.
"And I am actually confident, I've talked to some of you individually, that it will end up being the smart thing to do politically because I believe that good policy is good politics," he added.
Obama has staked much of his political capital on the reforms.
Asked whether they had managed to corral the 216 members needed to pass the bill, Hoyer told reporters: "Clearly we believe we have the votes."
Democrats set the stage for a series of House votes on Sunday: First on the "rule" to govern the debate, then a package of "fixes" to the Senate's version of the bill, and then the Senate bill itself.
"We want to make it absolutely clear that we're modifying the Senate bill," Democratic Representative Chris Van Hollen, a close ally of Democratic House Speaker Nancy Pelosi, told reporters.
Van Hollen said that Democrats would go for a direct up-or-down vote on the Senate plan, having dropped a controversial earlier plan, much mocked by Republicans, to avoid it.
At least one Democrat had indicated he wanted to back the overhaul but could not vote for that approach.
If the measure clears the House with at least 216 votes, the Senate would take up the changes next week under rules that deny Republicans their most potent weapon, an indefinite delay called a filibuster.
The Democrats lack the votes to overcome such a tactic.
Democrats raised the possibility that Obama could issue an executive order reaffirming the prohibition.
Outside the Capitol, demonstrator Andy Counts of Maryland denounced the bill as "an overreach of the government, too much socialism" as he waved a sign reading: "Lies. Bribes. Corrupt. Socialist. Rats."
Asked whether he expected to change lawmakers' minds, Counts demurred, but said: "This is a start for us, the beginning of another year, two years, of work to repeal this bill," starting with the November elections.
The White House touted support for the bill from the American Hospital Association, the American Medical Association -- top lobbies for US hospitals and doctors -- and the powerful AARP lobby group for the elderly.
Democrats also pointed to an estimate by the non-partisan Congressional Budget Office (CBO) that says the bill could cut 130 billion dollars from the bloated US deficit through 2019 and 1.2 trillion in the subsequent 10 years.
The CBO estimates the health care bill would cost 940 billion dollars over the next ten years.