Earlier this month, two former leaders of the Khmer Rouge, a murderous group that briefly ruled Cambodia in the 1970s, were convicted of genocide. The ruling was the first verdict on genocide by the tribunal, which is hearing KR-related cases. It's also likely to be the last; not because there are no more crimes to be investigated, but because Cambodia's leadership wants the tribunal to go away. That's a mistake. Justice is needed today more than ever; no national leader should ever think that he or she can escape an accounting for their actions.

From 1975 to 1979, the KR ruled Cambodia. Led by Pol Pot, the nom de guerre of Saloth Sar, they sought to re-create their country as a self-reliant agrarian nation. They tortured and executed enemies — real and imagined — along with their families, as well as anyone they considered "tainted": Wearing eyeglasses was enough to warrant that label. As many as 2 million people, about one-quarter of the population, died from murder, overwork or starvation.

That madness and the resulting instability prompted the Vietnamese to invade in 1979. They installed a former KR leader named Hun Sen as head of the new government; he remains in power to this day, a testimony to his guile and ruthlessness. The KR fought a low-level insurgency for over a decade, but the movement faded as thousands of its supporters defected to the government.