You'd been corrected on this argument two or three times even before you posted it to me. Don't dish that swill as fresh.
Either the secessionists were out of the Union, and were foreign nationals -- and you have virtually conceded that argument -- or they were not. You can't have it both ways and just do what you want.
Oh, but wait -- that is the point, isn't it, El Supremo?
Such is the plight of traitors.