Can someone explain to me what constitutes being "too insane" for GOP establishment support?

[BolivarianHero]

For instance, what makes Tom Coburn, Trent Lott, Rand Paul, Tom Tancredo, Joe Arpaio, Sharron Angle, Jesse Helms, and Michele Bachman (I'll stop there. It would take me all night to list all of the crazies.) suitable candidates while David Duke, Carl Paladino, and Christine O'Donnell get thrown under the bus?

With Duke I can understand the optics...Even though some of these other people are just as batshit crazy, the KKK connection creates a strong reaction of disgust (both real and out of a need to look disgusted) that alienates all but the lunatic fringe.

[BurtWorm]

1. Letting the Bush tax breaks for the ultrawealthy expire is too nuts for the GOP

[BolivarianHero]

2. Well obviously...

But I would hazard a guess that if O'Donnell were just a couple of states further southwest, she'd have the whole GOP establishment on board.