In a historic step toward justice, the United Nations Security Council passed a late-night resolution referring Darfur to the International Criminal Court (ICC) on March 31, 2005. Human Rights Watch played a crucial role in building support for the referral, from our initial research on the ground, early calls for accountability, and extensive advocacy with the press and diplomats worldwide. This month's referral of Darfur to the ICC by the U.N. Security Council is, we must hope, the beginning of the end of Darfur's awful nightmare and a belated start to ensuring justice and accountability for the crimes committed against the people of Darfur. Human Rights Watch now looks to the ICC prosecutor to respond swiftly and assume the responsibilities entrusted to him.