Have you been to the inland parts of California? They are horrible. In case of a split the conservative half of California would have the lowest per-capita income of any state in the union, Mississippi included. The liberal half would be the richest state in the union and could secure natural resources just fine while the conservative half would honestly probably be in need of almost immediate humanitarian intervention.
I've only ever been to San Diego and the "Inland Empire". I need to do a West Coast vacation at some point. I have been to very rural Nevada, Arizona, and New Mexico though and they remind me of the poorest parts of Mississippi (where I lived for a number of years) and West Virginia. I could imagine that without the support of the more distant and highly populated South, the extreme western edge of the Conservative nation would be relative easy pickings militarily.
Haha while I'm down with the blackjack and hookers I think the idea of the rational middle is a myth. There's little evidence this exists; it is mostly within the heads of people who define themselves as the reasonable middle as they usually have quite extreme policy views.
There's no rational version of the KKK, Neo-Nazis, 5%ers, etc, but there are plenty of Trump voters who aren't actually racists, but thought he was the least bad candidate. A lot of them are unhappy with him now, but thought maybe he'd tone down once in office. There's a huge chunk of people who are fairly reasonable and while strongly Republican, are able to contribute economically and culturally to society. It's easy to paint them all with a broad brush - some literally do the same thing with the left, assuming that the overwhelming majority want to put them in jail or take everything from them.
I think this is in part due to the ever increasing amount of competition for good jobs. I think most stereotypical WASPs feel that there isn't enough success to go around and they're scared that if *they* aren't in power, other races/religions/viewpoints will oppress them once they get in power. I think it's the vile nature of humanity - if someone has to have an advantage, it should be me.
I don't know what the answer is. I don't know how you make people value meritocracy and compassion, but I'm fairly sure splitting the nation isn't the way to do it.