Complex sentence: He resigned as Vitter's state director, not because of that controversy, but because he desired to return permanently in Baton Rouge, and the state directorship had required travel throughout the state to Vitter's seven district offices.
Split into simpler sentences: He resigned as Vitter's state director, not because of that controversym but because he desired to settle permanently in Baton Rouge. The state directorship had required travel throughout the state to Vitter's seven district offices.