The 1936 Constitution replaced the Congress of Soviets of the Soviet Union with the Supreme Soviet of the Soviet Union. Unlike its unicameral predecessor, the Supreme Soviet contained two chambers: the Soviet of the Union and the Soviet of Nationalities. The constitution empowered the Supreme Soviet to elect commissions, which performed most of the Supreme Soviet's work. The Central Executive Committee of the Congress of Soviets was replaced by the Presidium of the Supreme Soviet which, much like its predecessor, exercised the full powers of the Supreme Soviet between sessions and had the right to interpret laws. The Chairman of the Presidium of the Supreme Soviet became the titular head of state of the Soviet Union. The Council of People's Commissars, known after 1946 as the Council of Ministers, continued to act as the executive arm of the government.