Loyalists have the DoD and military who's duty it is to uphold the constitution. And the people in charge of the military take that VERY seriously.
This wouldn't last long at all.
For real, I don’t see any state having the balls to do it like South Carolina in 1861. Texas pops shyt but think about it. Many of the businesses and industries will suffer. For instance, what will Americas team do? No sports, no concerts, basically back in a shutdown but this time bullets on your neck. And no stimulus checks. But compensatory military service.
I honestly think a better solution is drawing up new boundaries for the 48 contiguous states. And offer states the ability to split.
Like north cal and south cal. East and west Tennessee. Atlanta. Appalachia. New Orleans should be the capital of the gulf coast state