The headline from today’s release of the monthly Kaiser survey on health care is going to be that there was a sudden dip of support for the ACA.

But putting that aside, the really shocking thing from the poll is the evidence of one of the strangest campaign failures ever: the failure of the Republican presidential field to make Mitt Romney’s health care record a major issue.

Here are the numbers. First, the context: as you might expect, Republicans really hate Barack Obama’s health care reform, with an 11/81 split against it and almost two-thirds “very unfavorable.” And those who know about the Massachusetts plan have a similar opinion, which isn’t strange since the basic structure is so similar (although lacking the important ingredient of Barack Obama, as I’ve argued): Republicans oppose Romneycare by a 6-1 margin.

But the key number isn’t how many Republicans dislike health care in Massachusetts; it’s how many don’t know enough to offer an opinion. That would be a whopping 77% (and even more telling, it’s the same number for likely primary voters as it is for all Republicans in the survey). Kaiser also asked about whether the Massachusetts reform was similar to the national reform law, with the same results: 69% of likely primary voters didn’t have an opinion. Of those who did, 18% said it was similar while 11% thought otherwise.

So here we are, just 10 weeks from the Iowa caucuses, and Mitt Romney’s opponents have so far completely failed to let Republican voters know about his (presumably) biggest weakness. Now, that’s not a big surprise; they’ve raised it only occasionally in the debates, and they’re only just now starting to move towards TV advertising. It does probably mean that GOP-aligned media outlets (conservative talk radio and Fox News) haven’t been raising the question of Romneycare very often, either.  Granted, there’s still time for his opponents to hit him on the issue, but the Kaiser numbers show that they’re basically starting from scratch, at least with rank-and-file voters.