In the 1970s, Yugoslavia's socialist regime became severely splintered into a liberal-decentralist nationalist faction led by Croatia and Slovenia that supported a decentralized federation to give greater autonomy to Croatia and Slovenia, versus a conservative-centralist nationalist faction led by Serbia that supported a centralized federation to secure Serbia's and the Serbs' interests across Yugoslavia – as they were the largest ethnic group in the country as a whole. From 1967 to 1972 in Croatia and 1968 and 1981 protests in Kosovo, nationalist doctrines and actions caused ethnic tensions that destabilized Yugoslavia. The suppression by the state of nationalists is believed to have had the effect of identifying Croat nationalism as the primary alternative to communism itself and made it a strong underground movement.