[I]t’s still amazing that someone who lost a race against zero serious orthodox conservatives is poised to win a race with a more conservative primary electorate while in the interim his signature public policy has become absolutely toxic to said electorate.My response to this has always been that the GOP electorate doesn't actually care about health care reform the same way it cares about, say, abortion or taxes on rich people. Or, as I'm now putting it, Republican voters strongly oppose Obamacare, but they don't care very much about the ACA. They strongly oppose the health care plan that Barack Obama and Nancy Peloci and Harry Reid crammed through Congress against the will of the American people, and they think it's an unconstitutional power grab that amounts to a government takeover that's going to bankrupt the nation by cutting Medicare and death panels and all. But they don't know or care anything about the exchanges, or the cost-cutting efforts, or most of the rest of it.
And that being the case, the similarities between the Massachusetts plan and ACA are pretty much irrelevant -- what matters is whether the Massachusetts plan is similar to Obamacare (that is, to a government takeover supported by Barack Obama with death panels and the rest). And it's not all that hard for Romney to deflect that, at least for those who are open to his candidacy otherwise. Because, of course, Romney can claim that he's 100% against Obamacare and 100% for fully repealing it, and mumble mumble jargon jargon it's totally different from what he was up to when he was governor.
Again, it's certainly possible that Republican party actors who oppose Romney for other reasons will settle on health care as the best way to convince voters he's unreliable. And if voters hear from GOP opinion leaders that Romney supported something identical to Obamacare, then they may turn against him based on that -- not because they inherently hate Romney's health care plan, but because they trust GOP opinion leaders. But as an attack from other candidates without the support of other leading conservatives, I've never thought that it's a very strong charge, because Romney can always respond with just as much disdain as the other candidates that he strongly opposes Obamacare and would repeal it as soon as possible.
Because, after all, Mitt Romney does hate Obamacare. He just doesn't really hate the ACA, but Republicans don't much care about that.