During its existence, the Soviet Union had three different constitutions enforced individually at different times between 31 January 1924 to 26 December 1991.
These constitutions shared and upheld most basic provisions including the Soviet Union as a socialist state, the leadership of the working class, the forms of social property, and called for a system of soviets (councils) to exercise governmental authority.
Soviet constitutions declared certain political rights, such as freedom of speech, freedom of assembly, and freedom of religion, and inline with the state Marxist-Leninist ideology also identified a series of economic and social rights, as well as a set of duties of all citizens.
Soviet constitutions established the bodies of the Government of the Soviet Union, outlined democratic rights, and stated the legislature was to be elected at periodical elections.
The 1936 Constitution received amendments in 1944 to allow the Soviet Union's constituent republics to be recognized as sovereign states in international law, resulting in the Ukrainian SSR and Byelorussian SSR joining the United Nations General Assembly as founding members in 1945.