Why is Medicare such a minefield for Republicans? John Sides over at the Monkey Cage today talks about it in terms of the political science idea of “issue ownership“ — the idea that at least in the short run, the images of the parties are relatively set among voters, and voters interpret campaign claims through those images, giving a party which “owns” an issue a much better chance of having their claims believed.

That works, essentially, outside of what the parties are saying or doing about the issue right now. So put aside for a minute all the claims and counter-claims, and just focus on the electoral effects. If Medicare is a major issue, the odds are that people will tend to believe Democrats’ claims over Republicans, and in general they’ll be more likely to support Democrats.

What’s striking is that at least some Republicans believe, or at least say that they believe, that Medicare helps them now. National Review’s Yuval Levin, for example, argues that “Obamacare changed everything” and that now Medicare is more naturally a good issue for Republicans. What’s especially striking about this is that this conviction is directly contrary to what the current polls say. Sides gives some results, but I’ll add that the July Kaiser poll indicated that President Obama had about a ten point lead on Mitt Romney on four questions: handling Medicare, handling Medicaid, lowering health-care costs and even “dealing with the future of the 2010 health-care law.” Moreover, while Kaiser didn’t ask about Rep. Paul Ryan in particular, they did find that Congressional Democrats did a bit better than Congressional Republicans on all four of those questions.

What’s going on here? I think it’s, once again, epistemic closure: Republicans inside the information feedback look just don’t see that Republicans aren’t very popular on these issues. This is, indeed, exactly the problem with a closed information loop; it’s possible that Team Romney — and the outsiders who pushed Ryan on him — just didn’t realize how poorly some of his issues play for Republicans. After all, on Fox News it’s Obama who cut Medicare (never mind that Ryan’s budget contained the same cuts) and is setting up death panels (never mind that those are fictional, while real Medicare beneficiaries are seeing the donut hole close and are getting free preventative care as part of the Affordable Care Act).

But again, this argument isn’t really about whether Obama or Romney is actually better for seniors; it’s about electoral effects, and how their plans will be perceived. The theory of issue ownership suggests that it’s an issue for Republicans to avoid, as does the polling. To believe otherwise in the face of theory and evidence? Strikes me as the kind of thing that political parties get punished for rather quickly.