Updated 4:20 p.m. ET
Facing near unanimous Republican opposition and a serious divide among his own Democrats, President Barack Obama is using a highly unusual address to Congress on Wednesday to sell the country on the need to reform America's health care system.
The president took office vowing to overhaul a system whose costs are raging out of control while as many as 50 million Americans are without health insurance. Thousands of households talk bankruptcy daily because of medical bills and health care consumes nearly 20 percent of the gross domestic product.
But a failure among Mr. Obama's fellow Democrats to solidify their support behind his reforms, intense Republican attacks against the overhaul - including blatant falsehoods - and sagging poll numbers pushed the president into making Wednesday's speech.
So far, he has been unable to take full advantage of his party's significant majorities in both houses of Congress.
While polls show most Americans want to see the system changed, Republicans have inflamed the debate, and some moderate Democrats in so-called swing states - fearing punishment at the polls next year - have refused to back Mr. Obama on the government-run public health care option, a measure White Press Secretary Robert Gibbs told CBS' "The Early Show" was still on the table.
"What we're going to hear tonight is, the president's going to speak clearly and directly to the American people about what's in this bill for them," Gibbs said Wednesday.
Making the rounds of morning news shows, Gibbs said Obama will highlight his vision of a health care overhaul that secures the insurance people now have, makes affordable care accessible to those without it and cuts insurance costs for families and small businesses.
Discussing Obama's thinking, a senior administration official said the president will make a case for why he believes a government-run option is the best way to introduce greater competition into the system. The official, who discussed the speech on grounds of anonymity because preparations remain under way, also said Obama would offer to hear new ideas and he would not suggest any veto scenario at this time.
Gibbs said Wednesday morning that the president had not yet finished working on the speech.
Even as Obama prepared to speak to a joint session of Congress and a live television audience, the leader of the influential Senate Finance Committee raced to broker a bipartisan agreement on the president's top domestic priority.
Sen. Max Baucus has said the only chance for a bipartisan bill will be to leave the public option out, reports CBS News White House correspondent Chip Reid.
The Montana Democrat's $900 billion plan would offer privately owned cooperatives and charge insurers, drug companies and other health service providers fees to cover the costs. It would also require all Americans to purchase insurance with maximum fines of up to $950 for individuals and $3,800 for families above the poverty level who don't.
Baucus hopes to have an agreement from his "gang of six" senators - three Democrats and three Republicans - before the president's speech this evening.
The White House set a high bar for the rare presidential address, acknowledging the huge stakes and creating big expectations about the level of specificity Obama would provide.
The president has stressed repeatedly the broad goals for the sweeping health care overhaul he seeks, but has left the details to lawmakers. Through a hot summer of angry debate, he lost his grip on the process.
Aiming to reclaim it at a pivotal moment and open a final push for a bill, Obama said, "We do intend to get something done this year."
An Associated Press-GfK poll out Wednesday found that American disapproval of Obama's handling of health care has jumped to 52 percent.
The same survey shows that 49 percent now disapprove of his overall performance as president. In July, just 42 percent disapproved of how he was handling his job.
"I'm open to new ideas," the president said in an interview Wednesday on ABC's "Good Morning America" in which he previewed the themes of his speech. "We're not being rigid and ideological about this thing."
In that interview, the president also blamed himself for leaving "too much ambiguity out there" on his health care plan, reports CBS News White House correspondent Mark Knoller.
Mr. Obama said ambiguity in his plan allowed "opponents of reform to come in and to fill up the airwaves with a lot of nonsense."
That nonsense, he said, includes the "ridiculous idea that we were setting up death panels" or providing health insurance to illegal immigrants.
Republican Party Chairman Michael Steele dismissed the proposal in a separate interview, saying "the idea that the federal government can come in and be the same as Allstate in providing insurance, that's ridiculous." He also characterized the public option as socialist in an interview on CBS' "The Early Show".
Gibbs argued that a government-run option is "supported by a majority of people in this country" and said that currently "there's nobody to compete" in a situation where a private health care insurance company dominates the market.
With Obama's approximately 35-minute speech still being written, much by the president himself, White House officials said the president will "answer all the major questions" - including the sticky issue of how to pay for getting coverage for the 50 million Americans who lack it.
Sitting in first lady Michelle Obama's box in the House gallery will be Americans who have suffered from high costs and insurance practices, and Obama will mention some specifically in his remarks.
Obama will appear before lawmakers a day after their return from an August recess marked by contentious town halls and much misinformation and confusion about what a health care overhaul may look like.
At a news conference Wednesday, House Minority Leader John Boehner said the president should "hit the reset button" and start over on health care reform.
"I hope he's been listening to the American people, because I think over the course of August they've raised their voices loud and clear that they don't want this massive government takeover of our health care system," Boehner said. "But it appears that the president's going to double down tonight and try to put lipstick on this pig and call it something else."
A senior administration official said Obama has ceased worrying about whether he gets any Republican participation. "If they don't want to, we can't worry about that," said the official, who spoke on condition of anonymity to more freely discuss behind-the-scenes thinking.
But that is no longer Obama's biggest difficulty, a fact underscored by the conflicting advice he was getting from within his own party.
"I hope he will call for a pragmatic, bipartisan approach," said Rep. Stephanie Herseth Sandlin, D-S.D., head of the fiscally conservative Blue Dog coalition. "I support necessary change, but not radical change."
Liberal Rep. Anthony Weiner, D-N.Y., said Obama must say he is prepared to fight for a public option. "That's how bills get passed," Weiner said. "It's that or a retreat."
Liberal group MoveOn.org, meanwhile, placed an ad in the New York Times today showing a petition signed by Obama campaign staffers, volunteers and donors arguing that a health care bill lacking a public option would be "letting the insurance companies win" and would not reflect "change we can believe in."