I explored social science on this topic a while ago. Ethnic division, check. Elite overcompetition for positions, check. The main countervailing trend is low birth rates which tend to mitigate against civil war. But here a different take on same subject. https://www.theamericanconservative.com/articles/the-enoch-powell-question/ …https://twitter.com/amconmag/status/1191336793775296512 …
This is stunningly optimistic. The US tried territorial division and co-sovereignty and Northern Puritans / Quakers couldn't stand the fact that they didn't rule the South as well. Post CWII there's got to be a solution to *that* problem and geographic division isn't it.