Updated

With the Senate Finance Committee poised to approve its version of health reform this week, Barack Obama is closer than any other president in history to remaking health care yet remains far off from achieving his top domestic priority.

That's because Republicans are nearly unified in opposition while Democrats are hardly united in support.

Few, if any, of the major disputes 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.

"The question is whether or not the Congress will ignore the will of the people expressed in town hall meetings around the country or whether the Congress is going to listen to the American people," said Rep. Dan Lungren, R-Calif., told FOX News Sunday.

The devil is in the details.

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 slashing Medicare and Medicaid payments to health care providers, and by ordering new taxes and fees that are already meeting fierce resistance. Insurers would no longer be able to turn away those in poor health.

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, or so called "public option," 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.

"The American people have said they do not trust a public option," Lungren told FOX News. "They don't want government taking over more and more of the health care they desire. They want us to go back and look at very specific things we can do."

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.

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 to 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. The Democrats have 60 votes in the Senate -- 58 from their party and two independents -- and that's the magic number needed to overcome roadblocks. But as yet there's no bill that 60 Democrats would agree to.

In the House, the third week of October is the earliest a bill could come to the floor, Hoyer said. Leaders are still meeting with rank-and-file Democrats to work through disagreements.

On Friday, more than 100 Democrats sent House Speaker Nancy Pelosi, D-Calif., a letter opposing the tax on high cost insurance in the Senate Finance plan. They argued the tax would ultimately be paid by middle-class union members who bargained hard for comprehensive health plans.

"The purpose of this letter is to put a big red flag in front of the White House and the congressional leadership," said Rep. Joe Courtney, D-Conn., who circulated the letter. "This will be a problem."

Finance Democrats have felt the pushback already. Baucus accepted an amendment by Sen. Jay Rockefeller, D-W.Va., that would ease the bite of the insurance tax on retirees over the age of 55 and for plans that cover workers in high-risk jobs like coal mining.

Still, the wrangling obscures considerable agreement on what the health care system would look like after it's reengineered. Some of the outlines have emerged:

-- Although government will play a bigger role than it does now, most people will still be covered by private insurance plans sponsored by their employers.

-- Medicaid will be expanded to cover more low-income people, including childless adults for the first time.

-- Self-employed people and those working for a company that doesn't provide health insurance will be able to buy coverage through new insurance purchasing pools called exchanges. Government would provide tax credits for many middle class people. Insurers participating in the exchanges will have to take all applicants and will be limited in what they can charge those who are older and sicker.

-- Medicare would adopt a new philosophy geared to better coordinating care for seniors with chronic illnesses and trying to keep them out of the hospital.

Even Democrats who are upset with the Senate Finance bill say they're optimistic that Congress can get legislation to Obama.

"There is enough momentum now that I would disagree with the characterization that it's going to be impossible to meld the two sides," said Courtney, the Connecticut Democrat trying to derail the insurance tax. "My hope is it will be by Thanksgiving, and my honest opinion is closer to Christmas."

The Associated Press contributed to this report.