Since Nuremberg, international punishment for mass atrocities is pervasive, as an idea and as a practice. In fact, many observers regard the institutionalization of international punishment – i.e., the incarceration of perpetrators of genocide, crimes against humanity and war crimes – as a progress and as a promise: The international community, by and large, seems to have, at least rhetorically, agreed that criminal punishment rather than impunity or, e.g., summary executions, is the adequate reaction to mass atrocities.