George F. Kennan, the American diplomat and historian, served as a Civil Service officer in the Soviet Union during the 1930s, and his experience undoubtedly influenced his argument about Soviet foreign policy and the need for containment.
During his time in Moscow, Kennan witnessed firsthand the brutality and totalitarian nature of the Soviet regime. He also became fluent in the Russian language and gained a deep understanding of Russian culture and history.
These experiences shaped Kennan's views on Soviet expansionism and the need for the United States to adopt a policy of containment to counter Soviet aggression. In his famous "Long Telegram" and subsequent article in Foreign Affairs, Kennan argued that the Soviet Union was a deeply insecure and paranoid regime that saw itself in a perpetual struggle with the capitalist West.
Kennan's experiences in the Soviet Union, combined with his deep knowledge of Russian history and culture, gave him a unique perspective on Soviet foreign policy and helped to shape his influential argument for a policy of containment.