If you look at the counties Trump won, then NY, PA, NJ, VA, & FL would have the same problem—in state civil war.
Heck, even Illinois went almost 40% for Trump. Almost all the blue votes came from the Chicago area. The rest of the state won’t quietly sit by and allow Chicago to force them to leave the union.
As far as I can tell, Mass, Vermont, Conn, & RI are the only states that had more blue counties than red. Every other state (even CA) is dominated by red counties.
NO, If there is a referendum and states want to leave then they leave. There will be no nationwide civil war WHICH IS A GOOD THING. If there is war/strife inside a few states that have left the union so what? I DON’T CARE.