President Barack Obama hopes to use a major speech next week to revitalize his push for healthcare reform -- and his success or failure could help define the rest of his term and perhaps his presidency.

When he addresses a rare joint session of Congress on September 9, Obama must persuade lawmakers, and an increasingly skeptical public, that he can pay for the nearly $1 trillion plan without boosting the huge U.S. budget deficit or cutting health insurance coverage for those who already have it.

The Democratic president must also offer specifics and overcome issues that opponents have used to exploit anti-reform sentiments -- such as charges the reform plan would finance abortions, create bureaucratic death panels to decide who gets care or guarantee healthcare to illegal immigrants.

Obama's speech comes as flagging opinion poll numbers have convinced the White House it is time to find a new strategy for striking a deal.

In every presidency there are critical moments that become turning points and this could easily be one for Obama, because he has put so many chips on to healthcare reform, and it's been getting away from him in a major way, said Larry Sabato, a political science professor at the University of Virginia.

Aides have said the administration is open to compromise, but insist the president still supports the public option, a proposed government-run health insurance plan as an alternative option to private insurance that is heavily supported by Obama's liberal base.

The insurance industry strongly opposes the public option, and has spent millions lobbying against it.

In the quest for a middle ground, White House officials are talking to Senator Olympia Snowe, a moderate Republican from Maine, a state that backed Obama in the November 2008 presidential election.

SNOWE SOUGHT

Snowe is seen as Obama's best bet for winning any Republican Senate support at all for healthcare reform. The White House has said repeatedly it wants the plan to pass with support from members of both parties, although Democrats have the political power to push changes through unilaterally.

Snowe supports a compromise plan that would not initially include a public option, but would trigger the creation of a government program if insurance companies failed to meet cost and quality benchmarks.

Conversations are taking place on her safety-net fallback option as they have throughout the debate this year, as well as other approaches to make certain people have access to affordable options, Julia Wanzco, Snowe's spokeswoman, said.

Healthcare reform is one of the long list of problems on Obama's agenda, but unlike the recession and wars in Afghanistan and Iraq, which he inherited from his Republican predecessor, George W. Bush, healthcare is a defining issue for Obama, who has made it his top domestic policy priority.

This is a chance to bring it back together and to make his partisans in Congress stand up and cheer. That's really what it's about, Sabato said.

Obama knows he is unlikely to win over more than the one or two moderate Republicans, so he has to unite Democrats, Sabato said. Basically, I think his message to Democrats is, it's me or it's chaos, he said, referring to 1994, when then-President Bill Clinton's failed bid for healthcare reform helped cost the Democrats control of Congress.

OBAMA INJECTS SELF INTO DEBATE

A top Democrat, asking not to be identified by name, said Snowe's plan is our best hope for healthcare reform. The Democrat said it could draw some Republican support and keep that of some Democrats.

Some conservative Democrats have balked at the potential cost of reform, and expressed concern that the public option was too much government interference in the private insurance industry.

By making the speech, Obama is injecting himself squarely into the center of the debate after months leaving it largely to members of Congress and other surrogates to formulate a strategy and sell the overhaul to the public.

His timing is perfect, said Jim Kessler of Third Way, a centrist Democratic think tank. He said that after letting Congress lead the debate in the first nine months and shape the legislation, Obama can step in and push through a solution, now that lawmakers have hit some major sticking points.

Obama has broad goals of reducing healthcare costs and bringing medical insurance to the 46 million Americans who do not have it. But opponents have used suggestions that the plan would fund abortions, provide healthcare for illegal immigrants or deny treatment to older Americans to fuel public distrust.

Opponents also contend that the public option is a step toward socialism -- virtually taboo in U.S. politics.

With conservatives within the party shaping up as a formidable obstacle to the reform push, Democrats need to take their debate over the public option behind closed doors, analysts said.

We just need to get back to having a real discussion about healthcare. It's not about abortion or immigration or euthanasia, said Darrell West, director of governance studies at the Brookings Institution in Washington.

Without those issues, We'll be left with the question - do people want to pay for near universal coverage? And that's a debate worth having, he said.

(Additional reporting by Steve Holland, Donna Smith and Thomas Ferraro, editing by Howard Goller)

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