What's going on here?  In part, it's just a matter of who's polling.  There was a cycle in the poll numbers even at the height of the political battle over passage, because different pollsters tend to get numbers that are more or less favorable to the program.  That effect is even more pronounced now, because few people are polling on it regularly, so having a couple of reliably negative or reliably positive pollsters in a row can make it look as if there's been a big movement.

But while this effect probably accounts for some of the shift, that's not the whole answer.  When you compare each individual poll with prior polls by the same outfit, they all show a jump in unfavorables of roughly 3-5% since the fall.

Identifying the change is easier than identifying the cause, however.  We haven't had all that much negative news about effects of the law itself since November.  There are the lawsuits, of course, which probably aren't helping public perceptions.  But I don't know if I want to chalk up such a large jump to a few lawsuits.

We can definitively say what hasn't happened, however; the public is not getting very excited about all the front-loaded benefits like keeping your kid on your health insurance until they're twenty-six

Does this matter?  I think it does, in two ways.  Firstly, as several legal observers have noted, the Supreme Court is more likely to strike down Obamacare, or at least major pieces of it, if there's clearly a strong public sense that the Democrats overreached.  The Supremes are much less likely to overturn a very popular health care law that they think abuses the spirit of the commerce clause, than they are to overturn a health care law which abuses the spirit of the commerce clause, and is hated by a majority of the population.

And secondly, this is fundamentally what Democrats are going to be facing 2012 with.  Passing the law so that we could find out what was in it has turned out to be an abysmal failure as a political strategy.  Depending on how strong these feelings are, the GOP has a strong message for 2012: give us both houses and the presidency, and we'll get rid of it.  Sure, Democrats could stage a filibuster--but I'm not sure the actual Democrats in the Senate are going to, if they get stomped again in the elections.

I'm not saying that this is the most likely outcome: only that these polls make it a potential outcome.  I still tend to think that the most important factors in 2012 are going to be the weakness of the Republican field, and the strength of the economic recovery.  But this does raise some interesting questions about lock-in and American politics.  Most progressives and Democratic strategists assumed that once you got this thing passed, it would essentially become another sacred cow like Medicare and Social Security.  But those programs weren't unpopular when they passed.  This was.  Does that change the political calculus?