

Depends on if there would be enough Generals and Admirals who sided with blue states.
But red states would repeat the mistakes of the confederacy and rely on Southern ports, and the rest of the US would once again blockade the Gulf and destroy their supply lines.
Only difference now is red states can get supplies via air.

Good point, plus any sufficient naval blockade would also have some AA capabilities, at least for the Gulf. So they would have to be creative about getting supplies that way