Which US diplomat is noted for establishing the concept of containment during the Cold War?

The concept of containment, which was a cornerstone of U.S. foreign policy during the Cold War, is attributed to George Kennan. In 1946, Kennan, then a diplomat at the U.S. Embassy in Moscow, articulated the strategy in his famous "Long Telegram." He argued that the Soviet Union was inherently expansionist and proposed that the best way to prevent the spread of communism was through a policy of containment. This approach called for a robust U.S. response to any attempt by the Soviet Union to expand its influence in other countries. Kennan’s ideas were influential in shaping U.S. actions and policies during the Cold War, making him a pivotal figure in this historical period. Other figures, while key in their own right, either came to prominence at different times or focused on different strategies, which is why they are not associated with the origin of the containment policy.