Look, there's no mystery to this. We've occupied countries before. Germany, Japan and Italy after WWII to name three. We are now occupiers of Iraq after a war in which we prevailed. No mystery there. So our obligations are fixed by well-settled international law. We must follow due process of law with regard to prisoners, just as the UN dictates.
So, if you have any doubts that the US is capable of being as vicious a conqueror as Nazi Germany in France during WWII, just compare our treatment of those who resist our occupation with the French who resisted the Nazi's. I submit that the only difference is that Bush doesn't have a moustache.