WASHINGTON - Over time, certain ideas become irresistible. They start out as problematic. Later, no one can remember why.

Consider Tuesday's bipartisan ceremony in which President Obama signed the Edward M. Kennedy Serve America Act. Thirteen years ago, Republicans in Congress tried to kill Bill Clinton's AmeriCorps program. This year, Republicans and Democrats joined together to pass the largest expansion of service opportunities in decades. Tomorrow isn't always defined by yesterday.

Bear that in mind as you hear reports about this or that snag, controversy or disagreement over the effort to pass comprehensive health care reform. Because of its defeat in 1994, there will be a temptation to treat every dispute -- notably the recent reports of contention over the inclusion of a government-run option in a final bill -- as the first step toward the collapse of the process.

The "public plan" idea is a good one and the issue is important: If the government makes it possible for everyone to buy health coverage, one option among many should be a government-run health insurance plan akin to Medicare.

The genius here involves both politics and policy. Many liberals believe our entire health system should be scrapped in favor a government-run single-payer plan along Canadian or British lines. The problem is that single-payer is not only politically impossible; it would also cause significant disruptions in the existing system. The public option idea is a clever halfway house. It would allow the United States to move gradually toward a government-run system if -- and only if -- a substantial number of consumers freely chose to join such a plan. The market would test the idea's strength.

Private insurers hate the idea because they think the public plan would undercut them in the marketplace. This argument is, in some ways, self-refuting. If the private insurers are right that the government would actually provide health coverage more cheaply than the private companies, why shouldn't that option be available? Wouldn't it save taxpayers money in the long run?

But negotiations over health care will involve give-and-take. What if including a robust public plan has the effect of dooming a bill that gets affordable health insurance to everyone? Should public-plan advocates block any bill that doesn't contain their idea, as originally conceived? Of course not.

As a negotiating tactic, they should hold firm to get as close to a decent public plan as they can. Obama himself said at last month's health care summit that the public option "gives consumers more choices" and helps "keep the private sector honest, because there's some competition out there."

Yet Obama also acknowledged concerns that "private insurance plans might end up feeling overwhelmed" and said these worries were "serious" and "real." This suggested that a compromise is in the cards.

And in a little-noted session last week sponsored by the Kaiser Family Foundation, Nancy-Ann DeParle, the White House health reform director, suggested that payment rates to both doctors and hospitals could be set at similar rates in both public and private plans to make sure that private insurers weren't driven out of business.

Another possible compromise would be a bill that did not include a public plan as such, but instead provided a "trigger" that would bring such a plan into being if insurance costs went too high or if coverage rates were too low. And the unlikely alliance of the pharmaceutical industry and the liberal group Families USA has suggested that expanding Medicaid (which, after all, is a public plan) might be a way around a deadlock.

The biggest difference between now and the last time around is the emphasis on creative compromise in place of creative obstruction. Public plan advocates should stay at the table to keep things moving.

They should also remember the lessons of Tuesday's Serve America event, which, by the way, received scant media attention. That was sad, except for the fact that the media's indifference was a sign of how a once controversial idea has now won such wide acceptance. That acceptance, in turn, allowed for the big improvements in the program that Obama signed into law.

Someday, that will happen with universal health coverage. If a bill passes this year, enhancements in the program down the road will not be seen as controversial but as inevitable.

E.J. Dionne's column is distributed by the Washington Post Writers Group.