WASHINGTON - A U.S. Senate committee moved Tuesday toward a pivotal vote on a sweeping health care bill that fulfills President Barack Obama's top domestic priority. "It's time to get the job done," Finance Committee Chairman Max Baucus declared as he convened his panel for the long-anticipated action.

"This is our opportunity to make history," the Montana Democrat said. "Let us reform the health care system to control costs and premiums. Let us extend health care coverage to all Americans."

The expected approval by Baucus' committee would push a remake of the U.S. health care system closer to reality than it has been in decades. Four other congressional committees finished their work before August and for months all eyes have been on the Finance panel, the one whose moderate makeup most closely resembles the Senate as a whole.

The committee's centrist legislation is also seen as the best building block for a compromise plan that could find favor on the Senate floor.

Baucus' 10-year, $829-billion plan would, for the first time, require most Americans to purchase insurance and it also aims to hold down spiraling medical costs over the long term. But questions persist about whether it would truly provide access to affordable coverage, particularly for self employed people with solid middle class incomes.

Much work would lie ahead before a bill could arrive on Obama's desk, but action by the Finance Committee would mark a significant advance, capping numerous delays as Baucus held marathon negotiating sessions -- ultimately unsuccessful -- aimed at producing a bipartisan bill.

With Democrats holding a 13-10 majority on the committee, the outcome of Tuesday's vote, expected after several hours of discussion by senators, was not in doubt. The big question mark was whether moderate Sen. Olympia Snowe of Maine would become the first Republican to support a health overhaul bill. The legislation that passed the other House and Senate committees did so without a single Republican vote.

Snowe didn't tip her hand in her opening comments at Tuesday's meeting. Instead she used her time to pose a number of technical questions about bill-drafting procedures to the head of the Congressional Budget Office, who was present at senators' request.

The Finance Committee's top Republican, Chuck Grassley of Iowa, gave voice to the GOP's concerns about the bill, saying it was "moving on a slippery slope to more and more government control of health care."

"There's a lot in this bill that's just a consensus that needs to be done, but there are other provisions of this bill that raise a lot of questions," Grassley said, contending the legislation would mean higher costs for Americans.

One of the biggest unanswered questions is whether the legislation would slow punishing increases in the nation's health care costs, particularly for the majority who now have coverage through employers. The insurance industry insists it would shift new costs onto those who have coverage.

Congressional Budget Office Director Douglas Elmendorf, under questioning by Republican senators, acknowledged that the bill's total impact on the nation's health care costs is still unknown. The CBO has been able to establish that the legislation would reduce federal government deficits, but Elmendorf said his staff has not had time to evaluate its effects on privately insured people. Government programs pay about half the nation's annual $2.5 trillion health care tab.

Expanding coverage to the uninsured is likely to lead to more health care spending, Elmendorf said. But other provisions, such as a tax on high-premium health care plans, could push spending down. "We simply have not done the analysis to net that out," he said.

One Democrat expressed misgivings about the legislation. Sen. Ron Wyden of Oregon said the bill doesn't do enough to promote consumer choice and guarantee affordability. "We clearly have more to do," Wyden said, without revealing how he'll vote.

Once the Finance Committee has acted, the dealmaking can begin in earnest with Senate Majority Leader Harry Reid, D-Nev., working with White House staff, Baucus and others to blend the Finance bill with a more liberal version passed by the Health, Education, Labor and Pensions Committee.

Baucus' bill includes consumer protections such as limits on copays and deductibles and relies on federal subsidies to help lower-income families purchase coverage. Insurance companies would have to take all comers, and people could shop for insurance within new state marketplaces called exchanges.

Medicaid would be expanded, and though employers wouldn't be required to cover their workers, they'd have to pay a penalty for each employee who sought insurance with government subsidies. The bill is paid for by cuts to Medicare providers and new taxes on insurance companies and others.

Unlike the other health care bills in Congress, Baucus' would not allow the government to sell insurance in competition with private companies, a divisive element sought by liberals.

Last-minute changes made subsidies more generous and softened the penalties for those who don't comply with a proposed new mandate for everyone to buy insurance. The latter change drew the ire of the health insurance industry, which said that without a strong and enforceable requirement, not enough people would get insured and premiums would jump for everyone else.

A major question mark for Reid's negotiations is whether he will include some version of a so-called public plan in the merged bill. Across the Capitol, House Democratic leaders are working to finalize their bill, which does contain a public plan, and floor action is expected in both chambers in coming weeks. If passed, the legislation would then go to a conference committee to reconcile differences.