In October 1974, Vorster initiated a foreign policy of "Détente" seeking support for a constellation of Southern African states who would be a united front against a common enemy, communism. The use of white buffers states began to fail in 1974 with a coup in Portugal, known as the Carnation Revolution, and by 1975 black liberation groups were in control of its colonies of Angola and Mozambique. BOSS was instrumental in organizing the search for influential allies in the region and arranging the meetings. This policy was soon destroyed by the South African invasion of Angola in 1975 and in June 1976 with the Soweto riots.