 Complete the following phrase:  Following the Treaty on the Creation of the USSR of 1922, the Russian Soviet Socialist Federative Republic, Ukrainian Socialist Soviet Republic, the Byelorussian Socialist Soviet Republic and the Transcaucasian Socialist Federative Soviet Republic established the Union of Soviet Socialist Republics USSR. The treaty established the government, which was later legitimised by the adoption of the first Soviet constitution in 1924. The 1924 constitution made the government responsible to the Congress of Soviets of the Soviet Union. In 1936, the state system was reformed with the enactment of a new constitution. It abolished the Congress of Soviets and established the Supreme Soviet of the Soviet Union in its place. At the 1st Plenary Session of the II Supreme Soviet in 1946 the government was renamed Council of Ministers. Minor changes were introduced with the enactment of the 1977 constitution. The CPSUs 