Nope, I'm afraid all the states will have to fall, even Texas. A huge purging then maybe (in tiny letters) a resurgence of those who thought ahead.
“How about the enemies within? Houston, Austin, etc.?”
I feel that the enemies within will get out of Texas just as fast as their Priuses will take them.
You obviously don't know Texans very well. There's a will amongst most Texans that's akin to something like a distilled and concentrated originalist American mindset.
I say that as someone who's a Texan by choice.