Washington ? Eight months in office, Barack Obama has now pushed closer than any other president in generations to creating a basic health care safety net for working Americans. Yet the fate of legislation delivering on his goal is far from certain: Republicans are nearly unified in opposition, Democrats hardly united in support.

Indeed, few if any of the major arguments about the scope and costs of the historic undertaking are settled as congressional leaders prepare to take legislation to the floor in the next two weeks.

Democrats on the Senate Finance Committee came together early Friday — after 2 a.m. — to finish the heavy lifting on a bill designed to appeal to moderates. Obama hailed it as a milestone and noted, for history, that overhauling health care has eluded presidents from Harry S. Truman to Richard Nixon to Bill Clinton.

“We are now closer than ever before to finally passing reform that will offer security to those who have coverage and affordable insurance to those who don’t,” Obama said.

But not yet. And not for sure.

Government plan

The 10-year, $900 billion bill would remake one-sixth of the U.S. economy, clearing a path to health insurance for millions who don’t have it now. It would be financed by reducing Medicare and Medicaid payments to health care providers, and by ordering new taxes and fees that are already meeting resistance. Insurers would no longer be able to turn away those in poor health.

Final passage in the Finance Committee, a political bellwether, is all but assured next week. After that, things really start to get interesting.

Senate Democratic leaders will begin tugging on Finance Chairman Max Baucus’ hard-won compromise to try to meld it with a liberal-leaning version passed by the Senate Health, Education, Labor and Pensions Committee. That second version would allow the government to sell insurance in competition with private industry, a highly controversial issue, while the plan from Baucus, D-Mont., would not.

The government-run plan doesn’t appear to have the votes to clear the Senate. In the House, it’s the other way around. A bill that doesn’t include a government plan to compete with private insurers won’t get off the floor, Democratic leaders say.

Taxes

That’s not the only fault line.

The House plan taxes the wealthy to pay for subsidies needed to make health coverage affordable for millions who are now uninsured. The Senate instead taxes the health care haves — those with expensive insurance plans.

The House plan — and the Senate health committee bill — would require employers to offer coverage to their workers or pay a tax penalty. The Senate Finance bill has no requirement that employers offer coverage, although it would levy a charge on businesses whose workers end up getting government subsidies.

If lawmakers manage to work their way through those issues, they still won’t be safely through the political minefield. They’ll face contentious issues including how to deal with coverage for abortions and how to keep benefits from going to illegal immigrants.

“A lot of people have a lot of nonstarters, and they are different nonstarters,” said House Majority Leader Steny Hoyer, D-Md. “If you add up all the nonstarters, it makes it very difficult to pass a bill. When we get an agreement in the House, it will contain things some people will prefer weren’t in there. It will also contain things they want. As in every major piece of legislation, you have to find a balance.”

Keep it moving

Increasingly, Obama will have to step in to settle disputes and keep the bill moving forward. That will please some lawmakers and alienate others. He can’t afford to lose many of his fractious Democrats.

Polls show the public has many concerns and questions about the legislation. But for now, most Americans seem to want Congress to keep working.

Republicans are certain that the more people learn, the less they’ll like about the Democrats’ approach.

“What we know for sure about this proposal, the core of it will include half a trillion dollars in Medicare cuts over 10 years and hundreds of billions of dollars in tax increases on both individuals and businesses,” Senate Republican leader Mitch McConnell of Kentucky told reporters Friday.

Senate Majority Leader Harry Reid of Nevada has said he wants meld the Finance and health committee bills in fairly short order. He could have a bill on the floor the week after next, with debate expected to last for weeks.