Bosnia and Herzegovina, with a heterogeneous population, has been contested between Croat and Serb national movements since the late 19th century. Bosnia saw the conversion of a significant part of the Slavic population under Ottoman rule (until 1878) to Islam. Croat and Serb nationalist movements claimed the converts to be either Croats or Serbs, while historical evidence suggests that few inhabitants had any national identity before the late 19th century. Many Serbs felt disadvantaged in the Habsburg Monarchy which ruled Bosnia and Herzegovina between 1878 and 1918. The emerging Serbian nation state also laid claim to Bosnia. In this context Gavrilo Princip, a Bosnian Serb and member of a nationalist movement, assassinated Archduke Ferdinand in June 1914, triggering World War I. Following the war, Bosnia became part of Yugoslavia (until 1929 Kingdom of Serbs, Croats and Slovenes). In interwar Yugoslavia, a centralist monarchy under the Serb Karadjordjević dynasty dominated the country, resulting in widespread dissatisfaction among non-Serbs, whereas most Bosnian Serbs supported the state (Bataković 1996: 64-100). During World War II, Bosnia was annexed by fascist-led Croatia. The state engaged in genocide against the Jewish and the Serb populations. Many Serbs joined either the royalist and nationalist Četnik movement which sought to reestablish a Yugoslavia under Serb predominance or the Partisan movement, together with Croats and Muslims, which under leadership of the Communist Party strove to reconstitute a Federal Yugoslavia (Hoare 2006). As the Partisan movement won, Bosnia, which had ceased to exist as a distinct unit in 1919, became one of the six federal republics of Communist Yugoslavia. Communist Serbs held dominant positions in the republic, but a policy of promoting national equality sought to ensure the representation of all nations. While other republics had a dominant nation, Serbs, Muslims (following their recognition as a nation in the 1960s) and Croats had equal standing in the republic. This period saw a repression of nationalism expressed by all three nations in Bosnia, while at the same time an elaborate ‘ethnic key’ sought to ensure representation of members of all three nations through the republic (Andjelić 2003, 39-40). During the first free elections in Bosnia in 1990, most Serbs, as well as Croats and Muslims, voted for nationalist parties. The Serb Democratic Party (SDS), the dominant party among Bosnian Serb voters, supported an extreme nationalist policy and opposed Bosnian independence from Yugoslavia. The overwhelming majority of Muslims (after 1993, Bosniaks) and Croats on the other hand supported Bosnian independence. This split was reflected in a referendum on independence which was boycotted by most Serbs and supported by most Croats and Muslims. Following Bosnia’s declaration of independence, the Bosnian Serb leadership of the SDS, headed by Radovan Karadžić, sought to carve out a Serb-dominated territory to join Serbia. (However, many Serbs remained loyal to the Bosnian government and did not support the partition of Bosnia advocated by the SDS and Serbia under leadership of Slobodan Milosevic.) This dispute triggered the 1992-95 war and led to the establishment of a Serb Republic. Non-Serbs were systematically ‘ethnically cleansed’ from the territory to which the new RS laid claim or mass murdered (Shoup/Berg 1999: 128-187). In total, more than 100,000 inhabitants of Bosnia died in the three and a half year war, approximately two-thirds were Bosniaks and a quarter were Serbs—most of the Bosniak victims were civilians, whereas most Serb victims were soldiers (IDC 2007, 33-35). The war ended with the Dayton Peace Accords in 1995 which established a highly decentralized Bosnia with the Serb Republic as one of the country’s two entities. Whereas before the war Serbs had lived intermingled with the other groups throughout Bosnia, the war lead to a far-reaching homogenization of the territory. The state itself is governed by a complex power-sharing system, while Serbs enjoy political predominance in the unitary RS. After the war, the RS has maintained close ties with neighboring Serbia (and the Federal Republic of Yugoslavia until 2003), sanctioned by agreements on special relations that entities are entitled to conclude with neighboring countries. Cooperation at the state-level in Bosnia has been cumbersome and often only possible through imposition by external actors (Bose 2002).