He was Minister of Foreign Affairs (1957-1985) and chairman of the Supreme Soviet Presidium (1985-1988). Gromyko was responsible for many of the most important decisions in Soviet foreign policy. In the 1940s, he was called Mr. Nyet due to his frequent use of veto power in the UN Security Council. In 1943, he was the Soviet ambassador in the United States and in 1946 became the Permanent Representative of the USSR at the UN. After returning to the Soviet Union he assumed the post of Deputy Minister of Foreign Affairs. Afterward, in 1952 he became the Soviet Union’s ambassador to Great Britain. Gromyko was the main Soviet negotiator of the Nuclear Test Ban Treaty, SALT I and SALT II (nuclear arms limitation agreements in 1972 and 1979).