In April 1994, Juvénal Habyarimana, the president of the central African nation of Rwanda, was returning from peace negotiations that promised a halt to civil war with the rebel Rwandan Patriotic Front (RPF) when his plane was shot down by assailants yet unknown. His death provoked a period of horrific ethnic violence in the nation historically divided between the Hutu and Tutsi ethnic groups. Over the next several months an estimated 800,000 Rwandans—mostly Tutsis—were massacred in what most observers now agree was a genocidal campaign orchestrated by elements within the Hutu-dominated Rwandan government and armed forces. By July 1994, the RPF, which was led by Tutsis, had successfully seized control of the country, causing over a million Hutus to flee to Zaire and Tanzania. They settled in enormous and squalid refugee camps where supplies were inadequate...