At Plum Line today, I argued that ACA is unlikely to be a significant liability for Barack Obama this fall -- and at any rate, the current polling on it is unlikely to predict how it will play then.
And at PostPartisan, I talked about another aspect of what I find the most fascinating thing in this GOP nomination cycle: the almost complete endorsement shutout for Rick Santorum. This time, I suggested that in addition to the lack of support causing his recent slide in the polls, it may also have predicted it: perhaps one of the reasons the people who have worked with him aren't supporting him is because they didn't think he was national candidate material. Of course, as I mention there and have said before, there's also the possibility that many of them, even strong conservatives, really support Romney but just don't want to say so out loud.
I still basically think that Santorum could have had an excellent chance of winning the nomination had high-profile conservatives rallied to him after Iowa (yes, even if he had apparently finished a few votes behind Romney). That can't be proved, nor can we prove why they didn't. We sure know that it happened -- or, rather, didn't happen, however.