 After World War II , Croatia became a one @-@ party Socialist federal unit of the Socialist Federal Republic of Yugoslavia . Croatia was ruled by the Communists and enjoyed a degree of autonomy within the Yugoslav federation . In 1967 , a group of Croatian authors and linguists published the Declaration on the Status and Name of the Croatian Literary Language , demanding greater autonomy for the Croatian language . The declaration contributed to a national movement seeking greater civil rights and decentralization of the Yugoslav economy , culminating in the Croatian Spring of 1971 , which was suppressed by Yugoslav leadership . The 1974 Yugoslav Constitution gave increased autonomy to federal units , essentially fulfilling a goal of the Croatian Spring and providing a legal basis for independence of the <unk> constituents . 
