Democrats have 23 Senate seats up for re-election in 2012. Republicans have 10. Republicans could plausibly hold the House and win a Senate majority in 2012.

Thus, the GOP’s best chance to overhaul the overhaul is likely to be in 2013. Why? Recall all those foolish predictions that health care would become suddenly popular after passage. They ignored the timeline. People don’t appreciate what they do not yet have. The converse should, however, inform GOP strategy. People do not miss what they never had. In 2014, those 32 million Americans who lack coverage will begin to gain it. Politicians cannot easily cut entitlements once, well, people feel entitled to them. They are called third rails for a reason.

Congress has never repealed landmark social welfare legislation within years of passage. But previous major social legislation also enjoyed some significant measure of bipartisan support. The hyper-partisan nature of health care’s passage explains its vulnerability.

This vulnerability only matters if the GOP has a historic victory in 2012. That potential victory also means that Democrats must consider all that could still be lost. In this age of austerity, their vision of health care reform is on the line. And so is the Democratic vision itself.