Shall we expect some transatlantic military giant to step the ocean and crush us at a blow? Never! All the armies of Europe, Asia, and Africa combined, with all the treasure of the earth (our own excepted) in their military chest, with a Bonaparte for a commander, could not by force take a drink from the Ohio or make a track on the Blue Ridge in a trial of a thousand years. At what point then is the approach of danger to be expected? I answer. If it ever reach us it must spring up amongst us; it cannot come from abroad. If destruction be our lot we must ourselves be its author and finisher. As a nation of freemen we must live through all time or die by suicide.
Let's do a quick thought experiment and say there was an actual legal framework for states to leave the union. How do Republicans think that would go? Under no circumstances would any major city in the south go along with leaving. Republicans states are far more purple than elections would suggest due to voter suppression, election fraud, and gerrymandering. So in reality the confederate areas would just be poor rural areas. Add in the fact that the US holds the keys to all the military equipment and weapons, the confederate areas would turn into a lawless hell scape over night. And without nuclear weapons and no international agreements for defense, I'm sure Mexico and Cuba would love to reclaim some of their lost territory.
I can go on. But the main reason these idiots keep bringing this up is to suggest violence into getting their way. It's not even a viable option to even consider for them. The situation I made is a best case scenario for them to. If they tried to violently leave the union it would be couple million good old boys in trucks up against jets and tanks.