The 60-39 vote Saturday night cleared the way for a bruising, full-scale debate on the bill after lawmakers return from their break for Thursday's Thanksgiving holiday.

The legislation is designed to extend coverage to roughly 31 million of the nearly 50 million Americans who lack it, crack down on insurance company practices that deny or dilute benefits and curtail the growth of spending on medical care nationally.

The United States, with a population exceeding 300 million, is the only developed nation that does not have a comprehensive national health care plan. The government provides coverage for the poor and elderly, but most Americans rely on private insurance, usually received through their employers.

The spectator galleries were full for the unusual Saturday night showdown, and applause broke out briefly when the vote was announced. In a measure of the significance of the moment, senators sat quietly in their seats, standing only when they were called upon to vote.

In the final minutes of a daylong session, Majority Leader Harry Reid, a Democrat, accused Republicans of trying to stifle a historic debate the country needed.

"Imagine if, instead of debating whether to abolish slavery, instead of debating whether giving women and minorities the right to vote, those who disagreed had muted discussion and killed any vote," he said.

The Republican leader, Sen. Mitch McConnell, said the vote was anything but procedural - casting it as a referendum on the bill itself, which he said would raise taxes, cut the government's Medicare program that provides coverage for the elderly, and create a "massive and unsustainable debt."

For all the drama, the result of the Saturday night showdown had been sealed a few hours earlier, when two final Democratic holdouts, Sens. Mary Landrieu and Blanche Lincoln, announced they would join in clearing the way for a full debate.

"It is clear to me that doing nothing is not an option," said Landrieu, who won US$100 million in the legislation to help her state pay the costs of health care for the poor.

Lincoln, who faces a tough re-election next year, said the evening vote will "mark the beginning of consideration of this bill by the U.S. Senate, not the end."

Both stressed they were not committing in advance to vote for the bill that ultimately emerges from next month's debate.

Of particular contentiousness to moderates is a provision for the government to sell insurance in competition with private companies, subject to state approval - a part of Reid's bill expected to come under significant pressure as the debate unfolds.

Even so, their announcements marked a major victory for Reid and the White House in a year-end drive to enact the most sweeping changes to the nation's health care system in a half-century or more.

At the White House, press secretary Robert Gibbs issued a statement saying the president was gratified by the vote, which he says "brings us one step closer to ending insurance company abuses, reining in spiraling health care costs, providing stability and security to those with health insurance, and extending quality health coverage to those who lack it."

The legislation would require most Americans to carry insurance and provide subsidies to those who couldn't afford it. Large companies could incur costs if they did not provide coverage to their workforce. The insurance industry would come under significant new regulation under the bill, which would first ease and then ban the practice of denying coverage on the basis of pre-existing medical conditions.

Congressional budget analysts put the legislation's cost at US$979 billion over a decade and said it would reduce deficits over the same period while extending coverage to 94 percent of the eligible population.

The House of Representatives approved its version of the bill earlier this month on a near party line vote of 220-215, and Reid has said he wants the Senate to follow suit by year's end. Timing on any final compromise was unclear.