You actually think that phone companies, internet companies, and other companies would just stop selling their services to the biggest state in the union?
The Texas dollar would be worth a hell of a lot more than the U.S. dollar.
Mostly because their dollar would have commodity backing, and would not have interest and inflation attached to it by the Federal Reserve.
States have no authority or right to set foreign policy. If the federal government says we aren't doing commerce with a foreign country (Texas) then no state will be doing any commerce with them until the federal government says it's okay.
You could also expect all of the USA allies to boycott them as well. And possibly even a NATO backed blockade in the gulf of Mexico if Texas started doing business with enemies of the USA.
To strong Salty. Idiocy is not right. My apologies.
Texas is already far beyond Iran in terms of infrastructure. They are also not under sanctions.
You could expect Texas to get slapped with sanctions too. You can't slap the USA in the face and not get slapped back. If they seceded, the federal government would do everything they could to mage out a tough go for them.
Just look at Cuba, and they weren't even a state.