The president planned to describe his plan at the White House, a day after he said he was open to melding four Republican ideas into his proposal. In a measure of the partisanship that has dominated the battle, his embrace of those policies drew no plaudits from Republicans, and instead was designed more to coax votes from nervous Democratic moderates by demonstrating an attempt to cooperate with the other party.
"I like the idea that the president is working with Republicans and trying to find common ground," said Sen. Mark Pryor, a centrist Democrat from Arkansas. "I think that's a good place to be for him, I think that's what the American people want to see."
Mr. Obama's effort signaled the climax of a yearlong duel over his premier domestic priority, with the outcome still uncertain. Democratic leaders hope to muscle the overhaul package through Congress by month's end or sooner over what is expected to be unanimous Republican opposition, teeing up a pivotal issue for the November elections when control of Congress will be at stake.
"He'll reiterate why reform is so crucial and what it will mean for American families and businesses," said a White House official who described Mr. Obama's remarks on condition of anonymity to avoid upstaging the president.
Special Report: Health Care Reform
"What the president is trying to do here is to be able to say to the country, 'Listen, I've reached out. I did everything I could possibly do to get Republican support and they just wouldn't go along with it,'" CBS News chief Washington correspondent Bob Schieffer said. He added that the president's attempt to pass health care reform on a straight party line vote will be "very complicated."
"At this point he really doesn't have the votes to get that done. He's trying to set himself up in a position that if this fails, he can say it's the fault of the Republicans."
Mr. Obama has already made the basics of his plan clear. He would extend health coverage to about 30 million uninsured Americans, with a first-time mandate for nearly everyone to buy insurance; rein in the insurance industry by banning practices like denying coverage for the ill; expand pharmaceutical benefits for the elderly and give lower-income people subsidies to help them afford coverage. It would be paid for by raising taxes on upper-income Americans and culling savings from Medicare, the government program providing health care coverage to seniors.
It will be less expensive than the health care bill the House narrowly passed in November, and will contain no government-run insurance program to compete with private insurers.
In a letter to congressional leaders Tuesday, Mr. Obama went further. He said he was exploring Republican proposals for cracking down on fraudulent medical charges, revamping ways for resolving malpractice disputes, boosting doctors' reimbursements under the government-run Medicaid program for the poor, and offering tax incentives for curbing peoples' visits to doctors.
Even Republican sponsors of those plans said the inclusion of those proposals would not win their votes.
"That in and of itself doesn't change my support at all," said Iowa Sen. Charles Grassley, who has pushed for higher Medicaid payments to doctors but opposes much of what Mr. Obama wants to do.
Mr. Obama also used his letter to draw a line in the sand, rejecting Republican appeals to restart the health care debate. He said "piecemeal reform is not the best way" to achieve his health care goals - a clear message to Republicans and moderate Democrats who say the president should take a more modest, incremental approach to reshaping the health care system.
In mid-January, the health overhaul drive seemed to have sputtered out after Republicans captured the special Senate election in Democratic-leaning Massachusetts. That gave them 41 of the Senate's 100 votes - just enough to stop Democrats from shoving final legislation through that chamber.
Democrats are now aiming toward a two-step approach. The House would approve a sweeping Senate-passed overhaul bill, then both chambers would make changes in it - like making subsidies more generous - by passing a separate measure.
Democrats would use a fast-track process - called reconciliation - for that second bill that would let them approve it with only a majority of Senate votes. Budget reconciliation rules prohibit filibusters, which are delaying tactics meant to stall legislation. It takes 60 votes to halt a filibuster.
Republicans say that the reconciliation process should not be used for such major legislation and accuse Democrats of subverting the rules, but White House chief of staff Rahm Emanuel defended it Tuesday after meeting with top Democrats, calling it "a normal procedure."
An initial health overhaul bill squeaked through the House in November. The new bill will probably have eased restrictions on using federal funds for abortion - meaning some Democratic supporters may now vote "no." To compensate, leaders need to find support from three dozen Democrats - mostly moderates - who opposed the bill last fall.
To round up votes, Democratic leaders have been citing polls showing that many voters dislike the overall idea of a health overhaul but favor specific proposals. One presentation by the Democratic firm Lake Research Partners suggests that lawmakers emphasize benefits that would take effect this year, like preventing insurers from denying coverage to those already sick and beginning to improve seniors' pharmaceutical coverage.
House Speaker Nancy Pelosi said Tuesday that the abortion dispute cannot be resolved in the companion bill Democrats plan to use to settle the main differences between the health care reform bills passed by the House and Senate. That legislation would be limited to provisions that have budget impact. That means Democrats may have to pass a third bill, making an already complex situation even tougher.
The United States is the only major industrialized country that lacks universal health care. Nearly 50 million people are uninsured in the U.S.