Soviet leader. He was instrumental in removing Khrushchev from power (1964) and served as general secretary of the Communist Party of the USSR (1964-1982). In 1968 he enunciated the Brezhnev Doctrine, which asserted that the USSR could intervene in any Warsaw Pact country in which the Communist government was threatened. Soviet adherence to this doctrine was evidenced by the invasions of Czechoslovakia (1968) and Afghanistan (1979).