Following a referendum showing overwhelming support, Croatia's parliament voted to secede from Yugoslavia on the same day as Slovenia, defying Belgrade's federal authority. The declarations set off a cascade of conflict: the Yugoslav federal army intervened, ethnic Serb militias mobilized within Croatia, and within months full-scale war engulfed the region, part of the broader collapse of Yugoslavia through the 1990s.
Croatia's declaration came after months of rising tension, a May referendum in which over 93 percent of voters backed independence, and growing friction between Zagreb and the Serb-dominated federal government in Belgrade under Slobodan Milošević's influence.
The declaration, timed to coincide with Slovenia's own act of secession, was less an isolated event than the crack that split open Yugoslavia's brittle federal structure, held together for decades by Josip Broz Tito's personal authority and now unable to survive the nationalist pressures released after communism's collapse across Eastern Europe.
Within weeks, the Yugoslav People's Army moved against Slovenia, and by autumn full war had erupted in Croatia, particularly in Serb-majority regions like Krajina. The ensuing conflict, lasting until 1995, killed thousands and displaced hundreds of thousands, becoming one of the bloodiest chapters of Europe's post-Cold War landscape and a case study cited in later debates over humanitarian intervention and war crimes tribunals.