Even Texas would have to wall off Austin, Houston, and plan on mass murder behind its lines. When people propose insurrection, you should know that is their intent.
Peaceful displacement to those that don’t hold to the ideals of Texas, arrest if they don’t. But they can’t stay. Only those who are productive, law-abiding conservative citizens may stay.
(I don’t want to talk out of turn for Texas, I am assuming they are one the last large bastions of conservatism)