In 1946, the American Chargé d’Affaires in Moscow George F. Kennan proposed the concept of “containment” in his famous 8,000-word “long telegram” to the U.S. State Department. These suggestions became the foundation of U.S. Cold War policy in the 1940s.
The Russians can’t be trusted and they probably won’t be changed. The main element of U.S. policy toward the Soviet Union, Kennan declared, must be patient but firm and vigilant containment of Russian expansive tendencies.