He joined (1931) the Communist party and . In 1952 he became a secretary of the party's central committee. After suffering a slight political setback following Joseph Stalin's death, Brezhnev filled a number of party posts. In 1957, as protege of Nikita Khrushchev, he became a member of the presidium (later politburo) of the central committee. He was (1960-64) chairman of the presidium of the Supreme Soviet. When Khrushchev went out of power in 1964, which Brezhnev helped to engineer, he was named first secretary (later general secretary) of the Communist party. Although sharing power with Alexei Kosygin, Brezhnev emerged as the chief figure in Soviet politics. In 1968, in support of the Soviet invasion of Czechoslovakia, he made the Brezhnev doctrine, making sure that the USSR could intervene in the domestic affairs of any Soviet bloc nation if Communist rule were threatened. While maintaining a tight rein in Eastern Europe, he favoured closer relations with the Western powers, and he helped (1972-74) bring about a dÃÂ©tente with the United States.
In 1977 he assumed the presidency of the USSR, thereby becoming head of state and head of the party. During the late 1970s and early 1980s, cold war tensions returned with an acceleration in the arms race, the Soviet invasion of Afghanistan, and the continued intransigence toward political and economic reform within the Soviet bloc, such as the imposition of martial law in Poland. Following his death, he was succeeded by Yuri Andropov. Under Mikhail Gorbachev, Brezhnev's regime was criticized for its corruption and failed economic policies.