IMHO, if health care reform fails, in long term, it will create serious backlash against GOP, because people will realize their medical cost will go up, as it happened after 2000. Significant portion of people who are against it, teaparty members included, simply don't realize how expensive the system is. If 18% of GDP sounds abstract, the cut in pay check will be real. In 5-10 years, the cost will climb to 20%-25% of GDP. This was precisely what happened after Clinton's reform failed and that was why Obama had the momentum to get it through. If this happens again, the insurance will keep going up. Then, there will be two painful alternatives: either the federal and state budgets are doomed or medicare as we know it will disappear. Neither will be acceptable to sensible people. Then, the only choice available would be nationalized health care.
In short term Obama will take serious heat. But at least some of those who are against it will eventually realize what had happened: they just lost the opportunity to get affordable health care. Many of them will have to go to the free clinics, paid by government. The number of people who can not afford health insurance will keep going up.