For one thing, individual crimes, even a lot of them, can't abdicate an entire people's right to justice. Nor must people be saints to deserve protection from genocide. However execrable the perpetrators of the July 23 killings, their actions don't retroactively make them candidates for ethnic cleansing. As for suggestions of moral equivalence between the renegade Kosovars and Milosevic's men, they are absurd. There's no comparison between a systematic plan of ethnic cleansing and isolated acts of vengeance, however horrible. Still, there's a reason these revenge killings trouble us so. To be able to endorse the bombing and killing of other people, we need to see one side as innocent victims and the other as evil oppressors. Any act of retaliatory violence threatens to demolish these Manichaean constructs.