People can be sane and yet incredibly wrong. Someone like Rubio or even Rand Paul is, at least partly, trying to walk a fine line between sanity and protecting himself from an attack by the hordes of madmen who vote in the primaries. I don't like their positions, certainly, and because of their sanity I'd say they're possibly more dangerous than someone like Bachmann, but several of them are likeable and even civil. (Paul Ryan, I think, is such a type. He's very wrong, but he's quite bright, and he's actually quite likeable as a person once you get away from his budget and his insane position on abortion. If I were to have lunch with a member of the GOP, Ryan would actually be fairly high on my list.)
It's nice to think, and indeed I'd like to believe, that you can never divorce the man's voting record from the man. But that's not entirely true. There's an anecdote that when President Ford was a congressman, if he saw a homeless person during his walk to the Capital, he would give him his lunch without thinking twice, and then proceed to vote against school lunch subsidies for schoolkids, without ever seeing the contradiction. Is he a hypocrite? Well, maybe. But I think there's something deeper here about human nature: if presented with a problem that is near to us, and a problem that is far away or feels far away, we make them as if we were two different people. Currently, I live in Oklahoma, one of the reddest, most reactionary, Bill O'Reilly-watching states in the country. And the people who live here are hospitable and kind in a way that I've just never seen en masse up north. It's not really an active sin; it's a glitch (maybe) in the wiring of human psyches.
As for 2014: it seems likely that the Republicans are going to keep the House (and quite possibly take the Senate) due to the demographics of midterm elections (and, in the Senate's case, races in several reddish states with moderate Democratic incumbents), which will- quite wrongly- send the message that contrarian batshittery works. But, as you say, it remains to be seen.