Just thought I'd throw this out there:
What if Texas decided to close it's borders, all of them. Oil, cattle, farming, technology, Texas has it all. Ideally you would have to be a native Texas to live here, but that would be impractical so just close the borders now. Control exports of our products. What would we need to import? I can't think of anything. Hmmm..... of course we would make Crawford our token sanctuary city.