The term should be “shrugging,” not “going Galt.”
Absolutely horrid, and I’m an advocate for the peaceful breakup of the states.
For one thing, restricting trade across borders is never a good idea and never produces the intended results. “If goods don’t cross borders, soldiers will.” —Frederic Bastiat
If the US breaks up, then free and unrestricted trade has to be maintained between the precipitate countries. I suggest you pick up a copy of Sowell’s “Basic Economics” and read it cover to cover.
Also, you are weirdly optimistic about how other countries will respond to your scenario. If a red state secession or quasi-secession happens, the best case scenario is that every other nations laughs at the poor little Jesusland full of rednecks and gun freaks that will be begging to join the blue states within five years. I’m not saying that’s how it is, I’m saying that’s how it will be perceived by Canada, the UK, etc.
Restricting trade is socialism’s twin, they are both big-government interventions into the market. It’s sad to see so many people calling themselves capitalists who want to close borders, which is the antithesis of the free market. You people have swallowed the unions’ propaganda about free trade.
In short, create a micro-nation within the confines of the borders of Texas. While you would have to take "immigrants" from other states, make sure the state constitution forbids substantially most transfer payments and maintains a right-to-work status, while making the threshold to amend an insurmountable number.
ff