The prospect of lots of dead Americans always seems to be ignored when talk of Glorious Secession is in the air.
This isn't 1861. Americans aren't going to murder each other by the millions over a purely political question of union.
If it does come to one or several states seceding, there'll definitely be fireworks, and yes, some folks are going to pay the ultimate price, but put away the visions of the U.S. military invading any sovereign state to stop them from leaving. It simply will never happen.