A region of one of the large E.U. states may split off to become a new state. For a U.S. state to split into two would require the approval of the Congress and presumably the U.S. President. I also assume the E.U.’s legislative and executive branches would have to sign off on the addition of a new state. I am not referring to Bavaria, or even northern Italy. The region to which I refer is known as Scotland, in the state of Britain. An independent Scotland would presumably have to apply to become a state of the E.U.
The full essay is at Essays on Two Federal Empires.