“This is where we've ended up. It's an approach that has been debated and changed and I believe improved over the last year,” Obama said in excerpts released in advance of an appearance at the White House.

The president was also expected to endorse a plan by Democrats to try and enact the legislation by majority vote — using a Senate procedure that would deny Republicans the right to procedural delays.

His appeal came several days after the president convened a bipartisan summit with lawmakers of both parties, then released a revised plan that he said incorporated several Republican suggestions.

Even so, Republicans are solidly opposed to the legislation, demanding instead that Obama and Congress start over again.

At its core, Obama's proposal would extend health care to tens of millions of uninsured Americans, while cracking down on insurance company practices such as denying coverage on the basis of a pre-existing medical condition.

The United States is the only major industrialized country without universal health care.

Obama and congressional Democrats are working to mount a party-line rescue mission for the health care legislation that appeared on the cusp of passage late last year, only to be derailed when Republicans won a Massachusetts Senate seat that gave them the ability to stop it.

There is still no certainty about the outcome — or even that Democrats will agree to the series of changes that Obama said represented Republican contributions.

Whatever the final outcome, the issue is certain to reverberate in this year's congressional elections, a fact that both Obama and Senate Republican leader Mitch McConnell referred to.

“I don't know how this plays politically, but I know it's right. And so I ask Congress to finish its work, and I look forward to signing this reform into law,” the president said in the excerpts.

McConnell said that a decision by Democrats to invoke rules that bar delaying tactics would be “met with outrage” by voters, and he said Obama was pushing a sweeping bill that the public doesn't want.

“They've had enough of this yearlong effort to get a win for the Democratic Party at any price to the American people,” McConnell said on the Senate floor.

Even if Obama's maneuvering draws no Republican support, the White House and Democratic congressional leaders hope it will give comfort to moderate to conservative members of their own rank and file whose votes will be essential to passage.