America's political scene has changed immensely since the last time a Democratic president tried to reform health care.

So has the health care picture: With costs soaring and insurance dwindling, nobody can now say with a straight face that the U.S. health care system is OK. And if surveys such as the New York Times/CBS News poll released over the weekend are any indication, voters are ready for major change.

The question now is whether we will nonetheless fail to get that change, because a handful of Democratic senators are still determined to party like it's 1993.

And yes, I mean Democratic senators. The Republicans, with a few possible exceptions, have decided to do all they can to make the Obama administration a failure. Their role in the health care debate is purely that of spoilers who keep shouting the old slogans – Government-run health care! Socialism! Europe! – hoping that someone still cares.

The polls suggest that hardly anyone does. Voters, it seems, strongly favor a universal guarantee of coverage, and they mostly accept the idea that higher taxes may be needed to achieve that guarantee. What's more, they overwhelmingly favor precisely the feature of Democratic plans that Republicans denounce most fiercely as "socialized medicine": the creation of a public health insurance option that competes with private insurers.

Or to put it another way, in effect, voters support the health care plan jointly released by three House committees last week, which relies on a combination of subsidies and regulation to achieve universal coverage, and introduces a public plan to compete with insurers and hold down costs.

Yet it remains all too possible that health care reform will fail, as it has so many times before.

I'm not that worried about the issue of costs. Yes, the Congressional Budget Office's preliminary cost estimates for Senate plans were higher than expected, and caused considerable consternation last week.

But the fundamental fact is that we can afford universal health insurance – even those high estimates were less than the $1.8 trillion cost of the Bush tax cuts. Furthermore, Democratic leaders know that they have to pass a health care bill for the sake of their own survival. One way or another, the numbers will be brought in line.

The real risk is that health care reform will be undermined by "centrist" Democratic senators who either prevent the passage of a bill or insist on watering down key elements of reform. I use scare quotes around "centrist," by the way, because if the center means the position held by most Americans, the self-proclaimed centrists are in fact way out in right field.

What the balking Democrats seem most determined to do is to kill the public option, either by eliminating it or by carrying out a bait-and-switch, replacing a true public option with something meaningless. For the record, neither regional health cooperatives nor state-level public plans, both of which have been proposed as alternatives, would have the financial stability and bargaining power needed to bring down health care costs.

Whatever may be motivating these Democrats, they don't seem able to explain their reasons in public.

Thus Sen. Ben Nelson of Nebraska initially declared that the public option – which, remember, has overwhelming popular support – was a "deal-breaker." Why? Because he didn't think private insurers could compete: "At the end of the day, the public plan wins the day." Um, isn't the purpose of health care reform to protect American citizens, not insurance companies? Nelson softened his stand after reform advocates began a public campaign targeting him for his position on the public option.

And Sen. Kent Conrad of North Dakota offers a perfectly circular argument: We can't have the public option, because if we do, health care reform won't get the votes of senators like him. "In a 60-vote environment," he says (implicitly rejecting the idea, embraced by President Barack Obama, of bypassing the filibuster if necessary), "you've got to attract some Republicans as well as holding virtually all the Democrats together, and that, I don't believe, is possible with a pure public option."

Honestly, I don't know what these Democrats are trying to achieve. Yes, some of the balking senators receive large campaign contributions from the medical-industrial complex – but who in politics doesn't? If I had to guess, I'd say that what's really going on is that relatively conservative Democrats still cling to the old dream of becoming king makers, of recreating the bipartisan center that used to run America.

But this fantasy can't be allowed to stand in the way of giving America the health care reform it needs. This time, the alleged center must not hold.