Step-by-step explanation:
After the Allied victory in World War II, Yugoslavia was set up as a federation of six republics, with borders drawn along ethnic and historical lines: Bosnia and Herzegovina, Croatia, Macedonia, Montenegro, Serbia, and Slovenia. In addition, two autonomous provinces were established within Serbia: Vojvodina and Kosovo. Each of the republics had its own branch of the League of Communists of Yugoslavia party and a ruling elite, and any tensions were solved on the federal level. The Yugoslav model of state organisation, as well as a "middle way" between planned and liberal economy, had been a relative success, and the country experienced a period of strong economic growth and relative political stability up to the 1980s, under dictatorial rule of Josip Broz Tito. After his death in 1980, the weakened system of federal government was left unable to cope with rising economic and political challenges.
In the 1980s, Albanians of Kosovo started to demand that their autonomous province be granted the status of a constituent republic, starting with the 1981 protests. Ethnic tensions between Albanians and Kosovo Serbs remained high over the whole decade, which resulted in the growth of Serb opposition to the high autonomy of provinces and ineffective system of consensus at the federal level across Yugoslavia, which were seen as an obstacle for Serb interests. In 1987, Slobodan Milošević came to power in Serbia, and through a series of populist moves acquired de facto control over Kosovo, Vojvodina, and Montenegro, garnering a high level of support among Serbs for his centralist policies. Milošević was met with opposition by party leaders of the western republics of Slovenia and Croatia, who also advocated greater democratisation of the country in line with the Revolutions of 1989 in Eastern Europe. The League of Communists of Yugoslavia dissolved in January 1990 along federal lines. Republican communist organisations became the separate socialist parties.
During 1990, the socialists (former communists) lost power to ethnic separatist parties in the first multi-party elections held across the country, except in Serbia and Montenegro, where Milošević and his allies won. Nationalist rhetoric on all sides became increasingly heated. Between June 1991 and April 1992, four republics declared independence (only Serbia and Montenegro remained federated), but the status of ethnic Serbs outside Serbia and Montenegro, and that of ethnic Croats outside Croatia, remained unsolved. After a string of inter-ethnic incidents, the Yugoslav Wars ensued, first in Croatia and then, most severely, in multi-ethnic Bosnia and Herzegovina. The wars left long-term economic and political damage in the region, still felt there decades later.[1]
In political science the events and the surrounding issues have been described as furthering Balkanisation.[2]