I've been around the block too many times to believe that President Obama and the congressional Democrats will pull off the near-impossible and fix all that ails the health care system.

A screenwriter could easily conjure a Hollywood ending: Obama, by dint of his magic touch, manages to expand coverage to every American while reducing the cost of treatment, all without driving up the deficit, with just enough of a "public option" insurance plan to satisfy the liberals, with just enough lawsuit protection to satisfy the doctors, and in the end he wins grudging applause from the insurance companies and the Republicans and the consumers and the budget hawks and the trial lawyers and the hospitals...

Good luck with all that.

Obama is moving into the toughest phase of the health care fight - that would be the congressional devil-in-the-details sausage-making phase - and it's questionable whether any president could achieve what needs to be done, no matter how potent his skills as a salesman may be. There's a reason why substantive health care reform has remained unachievable since it was first floated nearly 90 years ago (when it was called "compulsory health insurance"). There are too many competing interests; moreover, the most powerful advocates for the status quo have long been  successful in equating reform with the bogeyman of the moment, be it socialism or communism.

For reform to be successful, Americans have to be willing to take a calculated leap into the unknown. Opponents of reform have the easy job; all they need to do is sow doubt. Americans may believe in the abstract that the health care system badly needs fixing, but if they can be persuaded that reform might somehow imperil the quality of their own health care, then it's game over and the status quo lobby wins.

President Clinton's first pollster, Stanley Greenberg, discovered all this back in '93. He went into the field to survey Americans, and found tremendous support for health care reform - yet we all know how that battle turned out in '94. And recently Greenberg went back into the field on his own to ask Americans how they felt about Barack Obama's push for health care reform...and guess what:

As Yogi Berra once remarked, it was deja vu all over again.

Greenberg now finds the same broad theoretical support for health care reform as in '93, and, more importantly, he finds the same soft underbelly of support as in '93 - which could again be exploited by those who are deft at sowing doubt.

Greenberg is credible on this issue precisely because he's a Democrat whose ultimate loyalty is to his polling numbers. Writing today in The New Republic, he recalls his reaction as he compared his new stats to his '93 stats: "Oh no. It can't be. Nothing's changed."

He observes: "Then and now, the country proclaimed its readiness for bold reform. In both instances, one-quarter say that the health care system 'has so many problems that we need to completely rebuild it'; half the country sees 'good things' in the current system, but believes 'some major changes are needed.' Then and now, about 60 percent of the public feel dissatisfied with the current health insurance system. Yet three-quarters are satisfied with their own health insurance - once again eerily parallel numbers."

He elaborates: "There's one...number that I have to highlight - the three-quarters that say they are 'satisfied' with their own insurance. Most are not at all satisfied with a system that has forced them to trade higher wages for continued health insurance coverage and other compromises. But those personal compromises to get satisfactory coverage will mean people can live a little longer with the status quo, and (they) want to make sure the proposed changes really will make things better for their families."

So the burden of proof is clearly on Obama to make a compelling case for reform.

Greenberg also finds, today as in '93, that Americans' general enthusiasm for health care reform is tempered by their skepticism toward government: "Yes, we're no longer living in the shadow of Ronald Reagan. But the country has maintained the same anxieties about government's ability to improve the system. The country divides evenly (in his new polling) on whether the greater risk is an unchanged status quo or government reforms that 'create new problems.' And, finally, Obama might want to pay attention to how closely his situation echoes Clinton's. Then and now, more people favor the president's health care plan than oppose it, but the supporters make up less than a majority. If anything, I found on most of these questions that the desire for change and support for reform was slightly stronger 16 years ago..."

As Greenberg makes abundantly clear, Obama's daunting challenge is obvious. People typically take a NIMBY approach to the health care reform issue. They generally support the concept, but if they come to believe that their own costs might go up, or that their own treatment options might be affected, or that the plan might require higher taxes on something, then they are prone to simply say "not in my backyard." Such was the Clinton experience in 1993 and 1994.

"And those dynamics are still in play," writes Greenberg. "In my recent polling, I found that voters are skeptical about claims that reform will reduce costs and personal health outlays. Claims about simplicity, information-technology modernization, and best practices don't seem to be enough to persuade them otherwise....And, while voters have great confidence in Obama and his administration, they are worried about the deficits and spending and the government bailouts of the irresponsible. So, while voters want to see a re-balancing away from greed and toward the public good, almost half the citizenry is worried the government may get it wrong."

And, going forward this summer, the Republicans can potentially exploit that worry with their own warnings about "government-run health care." As in this new video, for instance.

Granted, the Republicans have virtually nothing substantive to offer in this debate; granted, these days they are largely discredited as stewards of governance; and granted, they have little to say beyond saying No. But, if Stan Greenberg is right, a message of No might be enough to sow a sufficient amount of doubt. All of which means that Obama will soon be tested as never before.