How much more expensive things will be when they have to export them from a foreign nation that sits right next door?
Who exactly do you think will be importing from whom?
Look, you posted a map. That's cute.
Most of that red is pretty vacant real estate. The USA would probably import it's food from California and Iowa...much like we do know.
Where would this new "Confederation" import everything else
from? You'd lose all your network television and sports leagues (with those franchises leaving the new country). You'd have no manufacturing base...but hey...you'd have a lot of corn! Houston would lose NASA and the Western states would go broke because they'd have to buy all the federal land within their borders.
So far, sounds good to me!