The ability of Japan to defend itself against an invasion of the home islands is only an issue if we accept that the legitimate war aim of the Americans and allies in the Pacific was unconditional surrender. Such an objective, it seems to me, turns a war of defense into a war of vengeance. It's understandable, and certainly not without precedent, but the two are not the same.

The subsequent occupation and establishment of imperial domains does not prove that a given war was not, at least initially, defensive. It does cast some doubt on what were the true political aims of the war, however.

And I think you may have the advantage of me. I am nore sure to what you refer as "the southern war." I thought you referred to the Civil War, but perhaps I was wrong.