"Nullification" is a discredited theory that goes back to pre-Civil War days. It's the idea that States can "nullify" (declare invalid & non-enforceable) Federal laws and court rulings with which a State may disagree.
Apparently the South shall indeed rise again. In revolt against the Union. I would rather the Union revolt against the South, and leave those bigoted rednecks to fend for themselves. As we know they cannot.
I lived nearly 3 years in Alabama. I understand how they're locked into some kind of backward pre-Civll War mentality.
Texas is very similar, added to which is their few years as an independent nation, after they broke from Mexico. They may have subsequently joined the US on paper, but never in spirit. They still view themselves as separate from the rest of the US. I'd cut them loose, too, since it appears to be what they want themselves.