GENOCIDE IS A uniquely horrific crime . Not because it is the bloodiest: Stalin and Mao killed many more people in gulags and famines than the nearly 6m Jews murdered by the Nazis. But the Holocaust was seen as so monstrous that the UN adopted the Genocide Convention, promising never again to allow an attempt to wipe out a group of people, or part of one, simply because of their nationality, race, religion or ethnicity. That promise has been repeatedly broken—in Bosnia, Darfur and Rwanda, to name a few. Each new case brought before the International Court of Justice (ICJ)...