Timothy William Waters, a professor at Indiana University Maurer School of Law and a Humboldt Fellow at the Max Planck Institute for Comparative Public Law and International Law, worked at the ICTY on Slobodan Milosevic’s trial.

Rarely does one read such hopeful news: In late June, the International Criminal Tribunal for the former Yugoslavia acquitted former Bosnian Serb leader Radovan Karadzic of genocide. That might sound like a bad thing: Karadzic, who once warned Bosnia’s Muslims that war would lead them down the road to hell, surely deserved to be sentenced for the acts of which he was just acquitted – murder, siege and slaughter almost beyond naming. But for genocide? Better not.

In fact, we would be better off getting rid of genocide as a crime altogether. The legal concept of genocide is so incoherent, so harmful to the purposes that international law serves, that it would be better if we had never invented it. Karadzic’s acquittal – precisely because he is still on trial on other counts related to the same atrocities – is an opportunity to move toward the sensible goal of retiring it.

This was not just any acquittal. The ICTY decided that, after a two-year trial, the prosecution had not presented enough evidence for any judge to find Karadzic guilty of genocide early in the Bosnian War (he faces a separate count for the July 1995 massacre at Srebrenica, and the prosecution is appealing the acquittal). The court has been consistent: With just a few trials left, it has issued no convictions for genocide apart from Srebrenica...