Bottom line:
If the SCOTUS rules it unconstitutional this summer it will be a non-issue.
If the SCOTUS rules it constitutional this summer there will be one hell of a fight.
Obama was SMART to get the "good parts" to kick in before the 2012 election. It will make it an easier sell in November.
Actually, nomintating Romney effectively nullifies this issue regardless of how the SCOTUS rules on it. What's Romney really going to say?
Romney's only pretending to be for repeal until he gets the nomination, then he'll never talk about it again.