The world invoked the vow "never again!" after the genocide in Rwanda and atrocities in Srebrenica. Then came Darfur. Over the past four years, at least 200,000 people have been killed and 2.5 million driven from their homes, and mass rapes have once more been used as a weapon of war in a brutal campaign by Janjaweed militias and the Sudanese government against civilians in Darfur. FRONTLINE producer Neil Docherty asks why the international community and the United Nations have once again failed to stop the slaughter.