Take, for instance, the perennial favorite example of message boards, Nazi Germany. In Nazi Germany, it was illegal to be a Jew, homosexual, Communist, or Jehovah’s Witness, and these people were put in concentration camps. So the allies win, they come in, and they set the prisoners free, right? But wait. Surely even in Nazi Germany, such things as rape, robbery and murder were illegal (at least when done without the sanction of the Nazi Party). So presumably the concentration camps contained prisoners who were there for not-so-innocent reasons. Just because someone opposes an evil regime doesn’t mean they’re good. So how is this handled? Do the conquerers say “Well, anyone conviction under Nazi rule is invalid, so you’re all free to go?” Do they have hearings to evaluate the legitimacy of the charges?
What about charges stemming from events during the war? Is killing a cop after the war a capital crime, but killing one during the war an act of resistance? Does “it was justified by the war” become a defense? If so, is it an affirmative one? If the wartime governent provided exemptions from prosecution for certain crimes (eg murder is illegal, unless it’s of a Jew), or didn’t recognize some things as crimes, will the new government retroactively declare these to be illegal?
The case of Germany is the first that jumps to mind, but I’m curious as to how occupiers in general have handled these questions.