The Socialist Federal Republic of Yugoslavia was not a part of the Warsaw Pact but pursued its own version of Communism under Josip Broz Tito. It was a multi-ethnic state which Tito was able to maintain through a Yugoslav patriotic doctrine of "Brotherhood and unity". Tensions between ethnicities began to escalate, however, with the Croatian Spring of 1970–71, a movement for greater Croatian autonomy, which was suppressed. Constitutional changes were instituted in 1974, and the 1974 Yugoslav Constitution devolved some federal powers to the constituent republics and provinces. After Tito's death in 1980 ethnic tensions grew, first in Albanian-majority SAP Kosovo with the 1981 protests in Kosovo.