Arkady ShevchenkoArkady Nikolayevich Shevchenko (, ; October 11, 1930 – February 28, 1998), a Soviet diplomat, was the highest-ranking Soviet official to defect to the West.
Shevchenko joined the diplomatic service of the Soviet Union, the Ministry of Foreign Affairs, as a young man and rose through its ranks, becoming advisor to Andrei Gromyko, Minister for Foreign Affairs. In 1973, he was appointed Under Secretary General (USG) of the United Nations. During his assignment at the UN headquarters in New York City, Shevchenko began passing Soviet secrets to the CIA. In 1978, he cut his ties to the Soviet Union and defected to the United States. Provided by Wikipedia