 In the 1945 election , the Communists were unopposed because the other parties <unk> . Once in power , the Communists introduced a single @-@ party political system , in which the Communist Party of Yugoslavia was the ruling party and the Communist Party of Croatia was its branch . In 1971 , the Croatian national movement , which sought greater civil rights and the <unk> of the Yugoslav economy , culminated in the Croatian Spring , which was suppressed by the Yugoslav leadership . In January 1990 , the Communist Party fragmented along national lines ; the Croatian faction demanded a looser federation . 
