The new division won’t be state to state, or county to county. It will be door to door. Talk of secession is silly and immature - a modern secession movement would be much more catastrophic as the last one we tried.
Perhaps. But the only other alternatives are one side or the other leaves and goes elsewhere (fat chance) or we suffer a Cultural Revolution-style purge. The old society is dead, and the Brave New society does not have room for everyone.
Yep, the future of revolution/civil war in the US can be found in the history books detailing the break up of Yugoslavia. The political dynamics will be different; the violence on a block to block level will be the same, though.