During its 69-year history, the Soviet Union usually had a de facto leader who would not always necessarily be head of state or even head of government but almost always held office as Communist Party General Secretary. The office of the chairman of the Council of Ministers was comparable to a prime minister in the First World whereas the office of the chairman of the Presidium was comparable to a president. According to Marxist-Leninist ideology, the head of the Soviet state was a collegiate body of the vanguard party (as described in Lenin's What Is to Be Done?).
Following Joseph Stalin's consolidation of power in the late 1920s, the post of the general secretary of the Central Committee of the Communist Party became synonymous with leader of the Soviet Union, because the post controlled both the Communist Party and (via party membership) the Soviet government. Often the general secretary also held high positions in the government. Since the post of general secretary lacked clear guidelines of succession, the office's successor needed the support of the Political Bureau (Politburo), the Central Committee, or another government or party apparatus to consolidate power. The President of the Soviet Union, an office created in March 1990, replaced the general secretary as the highest Soviet political office.