I think we’ll know after the next midterms. If the Republicans clean the Democrats’ clocks in the midterms, as I believe they will, then we’ll get another Romney clone for the next presidential election. If, on the other hand, they lose seats in the house, or worse, lose the house, then I think pragmatism and self preservation will kick in and we’ll see some new faces come presidential primary time, with more moderates than ideological purists and nut-jobs.
The Pubbies still do have a big tent. They’ve welcomed the misogynists, homophobes, xenophobes, anti-intellectuals, racists, and quite a surprising number of self-hating blacks with open arms, but that’s a short-term strategy, and not a winning one.
With the party’s recent trajectory, if they don’t moderate, I don’t think the Republicans can win another presidential election. They can, however, cause a lot of damage in the midterms.