@evan Yeah, I agree. My impression growing up (again, very Maryland- (maybe Baltimore)-specific) was that "War Between the States" was a shibboleth to communicate that you're the kind of person who would *RATHER* be saying "The War of Northern Aggression", but know that's not socially acceptable anymore.
IOW, "the War Between the States" was my childhood's "All Lives Matter".
Great point re: pre-war political units, I'll respond more fully on that because I too think that's fascinating.