Bosnia-Herzegovina (BiH) was the most ethnically divided of the six Yugoslav republics when it broke apart, with three large ethno-national identities, none of which constituted a majority: Bosnians (mostly Muslim), Serbs (mostly Serbian Orthodox Christians), and Croats (mostly Roman Catholics). Although these groups co-existed peacefully within Yugoslavia, violent conflict among them broke out at the time of independence, and the United Nations Protection Force (UNPROFOR) was created to end the violence. The United States brokered the Dayton Accords in 1995 ending the violence and creating two entities: the Bosnian-Croat Federation and the Republica Srpska. Under Dayton, the OSCE was tasked with managing the political, humanitarian, and disarmament components of the Dayton Accords. ODIHR managed efforts at democracy-building, while the Conflict Prevention Centre focused on disarmament, arms control, and confidence-building measures, as the OSCE mission approached 1000 international and local staff, the largest of any of its “missions of long duration.” Thirty years later, in 2025, the OSCE mission was still present as BiH remained divided, and opposition by the Republica Srpska largely blocked its entry into the European Union.