How climate change legislation and financial reform depend on the health care debate.For most of 2009, the public option-a hypothetical government-run health insurance plan that, if created, would compete with profit-driven, millionaire-making insurance companies-has defined the health care debate. Other issues pit liberals against conservatives, reformers against skeptics, but none has inspired the sort of passion that the public option has: Republicans and conservative Democrats reject it vehemently. Progressives say public option or bust.No matter what side of the argument you find yourself on, though, President Obama's position on the issue will leave you disappointed. He says that the public option is a good idea, but it's not, on the merits, a policy that will make or break health care reform on substantive grounds, and he thinks it's surprising and unfortunate that it's become the redline for progressives.The best you can say about that position is that it's about half right. At this point, the public option is unlikely, in the early years of reform, to be a revolutionary force in the health care system. But, politically, it was critical to keeping activists hopeful about an otherwise-uninspiring policy designed to keep deep-pocketed stakeholders from revolting, and killing reform altogether. That progressives have, to this point, prevented those stakeholders, and conservative politicians, from killing the public option, is an unalloyed good. It's good because, without their support, the reform effort will perish; good because the public option remains a good idea, and one that can be improved upon; and good because they are proving that they won't push over and let a consensus oriented President sell out the change he promised.As originally conceived, the public option would have been transformational-it would have forced insurance companies to do what they're supposed to do (pool risk, and finance health care) or driven them out of business. That public option was the compromise away from single payer that was still promising enough to keep the large and passionate base of single-payer supporters engaged in debate and willing to go to the mat for a plan otherwise designed to appease, or even strengthen, the for-profit health care industry.After months of political wrangling and compromise, the public option will more likely be a fail safe-a small program that can be expanded and strengthened if insurance companies continue to do a disservice to the country, and a safe harbor for people who, forced to purchase some kind of insurance, won't want to hand over their money to the same untrustworthy companies that have abused them and their friends and families for generations.Progressives have sacrificed plenty on this score already. What was once envisioned to be a government program that provided a service to many tens of millions of taxpayers, and used its sheer heft to pummel private insurers, doctors, hospitals, and drug manufacturers into completely overhauling their incentives, will now likely be just another medium-sized insurer, that can compete because it won't have to turn a profit. But though the legislative process has stripped the public option of its greatest promise, liberals will do themselves a disservices if they ease up or fold now that a health care bill seems within reach.They should continue their fight to keep the public option in the reform package, and, if possible, to strengthen it. If they allow the public option to wither on the vine, and lose its political import, they will make it extremely difficult for the government to ever circle back, and create a government insurance plan for middle-class workers.But, more crucially, they will send a message-to the administration, to well-heeled interest groups, to "centrist" politicians and Republicans-that they don't, at the end of the day, have the wherewithal to scuttle legislation that isn't good enough. If that happens, the pattern that's already been set in place will continue, and quite possibly worsen. Obama and Democratic leaders will introduce more, ambitious proposals, then do the easy thing and let corporations and their congressional surrogates render them all but useless.If those same leaders learn that their only hope for success is to twist other people's arms, then perhaps there's hope that the next big projects-climate change, financial reform-won't be long exercises in disenchantment.