History suggests that the best kinds of progressive social policy, see e.g. Social Security and Medicare, become virtually unassailable once they become institutionalized, a part of the fabric of expectations of all citizens. (This is true in other countries as well -- both the Canadian single payer system and the British National Health Service have proven untouchable even under right wing governments.) Social Security and Medicare have in common their universality (well if you're old), simplicity, effectiveness, and broad based funding mechanisms and the fact that you will never, ever (Cato Institute fantasies notwithstanding) be able to take them away from people.
Whatever the Democrats ultimately do on health care reform, they need to keep these examples in mind. Otherwise, "Baucuscare" could turn out to be the Medicare Catastrophic Coverage Act of 1988. Concern over deficits or costs are completely misplaced at this point -- what is needed is a universal health plan with costs that can be afforded by the average person. Worry about the deficits later -- get a plan in place, make it a good one, and once established, the necessary funds will follow. The public will demand it.