‘The fact of genocide is as old as humanity’, wrote Jean-Paul Sartre. The law, however, is considerably younger. This dialectic of the ancient fact yet the modern law of genocide follows from the observation that, historically, genocide has gone unpunished. Hitler's famous comment, ‘who remembers the Armenians?’, is often cited in this regard. Yet the Nazis were only among the most recent to rely confidently on the reasonable presumption that an international culture of impunity would effectively shelter the most heinous perpetrators of crimes against humanity.

The explanation for this is straightforward: genocide was generally, although perhaps not exclusively, committed under the direction or, at the very least, with the benign complicity of the State where it took place. Usually, the crime was executed as a quite overt facet of State policy, particularly within the context of war or colonial conquest. Obviously, therefore, domestic prosecution was virtually unthinkable, even where the perpetrators did not in a technical sense benefit from some manner of legal immunity. Only in rare cases where the genocidal regime collapsed in its criminal frenzy, as in Germany or Rwanda, could accountability be considered.

The inertia of the legal systems where the crimes actually occurred did little to inspire other jurisdictions to intervene, although they had begun to do so with respect to certain other ‘international crimes’ such as piracy and the trafficking in persons, where the offenders were by and large individual villains rather than governments.