人民代議員大会
Ambartsumian jointed the Communist Party of the Soviet Union (CPSU) in 1940. In 1948 he became a member of the Central Committee (the executive branch) of the Communist Party of the Armenian SSR. Ambartsumian was also a member of the Supreme Soviet from 1950 to 1989 (3rd to 11th convocation sessions). In 1989 he was elected as a representative from Armenia to the Congress of People's Deputies of the Soviet Union in the first relatively free elections.