WASHINGTON - Senate Democrats confidently advanced heath-care legislation yesterday toward a make-or-break test vote in a push for Christmas-week passage. Republicans vowed to resist what they appeared unable to stop.

In the run-up to the vote, the escalation in rhetoric was remarkable on both sides of an issue that has divided the two political parties for months.

"This process is not legislation. This process is corruption," said Sen. Tom Coburn, R-Okla., referring to the last-minute flurry of dealmaking that enabled Majority Leader Harry Reid, D-Nev., and the White House to lock in the 60 votes needed to approve the legislation.

Democratic Sen. Sheldon Whitehouse of Rhode Island responded in near-Biblical terms. In a speech on the Senate floor, he said Republicans are embarked on a "no-holds barred mission of propaganda, obstruction and fear . . . There will be a reckoning. There will come a day of judgment about who was telling the truth."

Whatever else it was, the legislation represented the culmination of a year's work for Democrats, pressed by President Obama to remake the nation's health care system.

Under Senate rules, Democrats needed 60 votes on three separate occasions to pass the measure.

The first and most critical test was set for sometime this morning. Democrats said Nebraska Sen. Ben Nelson's announcement Saturday that he would vote for the bill gave them the support they needed.

Nelson came in for strong criticism from Republicans in Washington, who complained that he had won favorable treatment for his home state's Medicaid program. In a bit of political theater, they sought to open the bill up to extend it to all 50 states, but Democrats objected.

Nelson said it was the concern of Nebraska's Republican governor over expanded Medicaid costs in the health-care bill that led to a compromise to cover his state's estimated $45 million share over a decade.

Gov. Dave Heineman "contacted me and he said this is another unfunded federal mandate and it's going to stress the state budget, and I agreed with him," said the Democrat, who was himself a Nebraska governor in the 1990s.

"I said to the leader and others that this is something that has to be fixed. I didn't participate in the way it was fixed."

But Heineman expressed anything but gratitude, saying he had nothing to do with the compromise and calling the overhaul bill "bad news for Nebraska and bad news for America."

"Nebraskans did not ask for a special deal, only a fair deal," Heineman said in a statement yesterday.

In response, Nelson fired off a letter to Heineman saying he's prepared to ask that the provision covering Nebraska's Medicaid share "be removed from the amendment in conference, if it is your desire."

The criticism is only a taste of what Nelson has received since announcing Saturday that he would become the 60th vote needed to advance the landmark legislation.

Nelson's agreement to an abortion-related change in the bill drew criticism from Nebraska Right to Life, a longtime supporter, and the state's Catholic bishops, who issued a statement that they were "extremely disappointed" in him.

Asked if Republicans could prevent the bill's passage, Sen. John McCain, R-Ariz., said: "Probably not. But what we can do is continue winning the battle of American public opinion."

Democrats hoped Republicans would relent in the face of a clear 60-vote majority, but if GOP critics choose to do so, they could delay a final vote on the bill until early Christmas Eve.

The House has already passed legislation, and attempts to work out a compromise are expected to begin in the days after Christmas.

The Senate legislation is predicted to extend coverage to more than 30 million Americans and would ban industry practices such as denial of insurance on the basis of pre-existing medical conditions.

The Congressional Budget Office said it would reduce deficits by about $132 billion over a decade, and possibly much more in the 10 years that follow.

At its core, the legislation would create an insurance exchange where consumers could shop for affordable coverage that complies with new federal guidelines. Most Americans would be required to buy insurance, with subsidies available to help families making up to $88,000 in income afford the cost.

In a bow to Senate moderates, the measure lacks a government-run insurance option of the type that House Democrats placed in their bill.

Instead, the estimated 26 million Americans purchasing coverage through new insurance exchanges would have the option of signing up for privately owned, nonprofit nationwide plans overseen by the same federal agency office that supervises the system used by federal employees and members of Congress.

The full extent of Reid's maneuvering was still unclear.

Besides the funds and changes Nelson got, Vermont and Massachusetts won additional Medicaid funds; plastic surgeons were persuasive in their bid to strip out a proposed tax on elective plastic surgery; hospitals in the Dakotas, Wyoming and Montana won additional Medicare funds; and there was more money for hospitals in Hawaii to treat the uninsured.

While Nelson's vote was the decisive one to fall into place for the Democrats, only an unpredictable series of events has left them with the ability to gain 60 without any help from Republicans.

They began the year with a caucus of 58, including 56 Democrats and two independents. Pennsylvania Sen. Arlen Specter added to their ranks in April when he bolted from the Republican party, and Sen. Al Franken made it 60 when he was sworn into office in July after a long Minnesota recount.

It was only a few weeks before Massachusetts Sen. Edward M. Kennedy, a longtime advocate of universal health care, succumbed to brain cancer and Democrats reverted to 59 seats.

With a heavy push from Reid and the White House, and a request Kennedy wrote not long before his death, Democrats in the Massachusetts Legislature quickly changed state law so Gov. Deval Patrick could appoint a temporary replacement.

Paul Kirk, a longtime Kennedy associate and former chairman of the Democratic National Committee, was sworn in Sept. 25. "We're prepared to go to work," he said.