Not that I've ever followed the space closely, but I've never read a really good game theory based explanation of why they behave the way they do. It seems to be a feature of all one party political divisions that they revert to the extreme, and most of our country is a de facto one party system. It certainly seems to encourage politicians to behave in the "purest" possible way, but at some point, there's no where to go but crazy, where you come up on the fly with an explanation that the shooter is a "transsexual illegal leftist" without regard to facts, because if you don't say it someone else will and then you're the lefty.

When you have to protect both flanks, as you should have to in a two party system, there's a tension that pulls in both directions. When all the pull is only to one direction (and of course it happens on the left a lot, too, it's just that it's so much more obvious when it's a minority party who is for the most part also poor, uneducated and racist), the positive feedback will continue until implosion. The only thing that can stop it is a moderating force, which could easily come from more moderate people moving to rural areas.

I'm not going to say I'm a fan of Brian Kemp, but his rejection of Trump and his 52 point win give me hope. The cult of personality is cracking, though it's still intact for now. My vision of a moderating force that could help bring rural America back to reality is someone Jimmy Carter-like. I know that sounds weird, since the GOP looks at Carter as the worst president this side of WWII, but he's a mild mannered white Christian who speaks the language (Southern, I mean) and knows how to connect with rural America. They're waiting for a Messiah, and they thought they found it in Trump, but Trump only knows how to piss off libs, not how to actually bring back the jobs.