George Kennan is forever attached to one letter and one word. The letter is "X," the pseudonym he chose for an unorthodox article on Soviet policy in Foreign Affairs magazine in 1947. The word was "containment," the essence of the policy of maintaining peaceful pressure on the Soviet Union until a collapse of Communist rule that he regarded as inevitable.
His views had been communicated to the State Department in 1946 in what became known as "the long telegram." In it he declared that Moscow was "impervious to the logic of reason" but "highly sensitive to the logic of force."
Mr. Kennan had a strong affection for the Russian people and strong contempt for its rulers. In 1952, serving in his fifth month as ambassador to Moscow, he went out to West Berlin on leave. There, he remarked to a reporter that life in Moscow was like life in a German prison camp, except that in Moscow "we are at liberty to go out and walk the streets ... under guard."
Josef Stalin declared Kennan persona non grata, and the diplomat returned to Washington where he soon became embroiled in strong disagreements with President Eisenhower's hawkish secretary of State, John Foster Dulles.
Kennan had reservations about the war in Korea and opposed intervention in Vietnam. He opposed the development of the hydrogen bomb and he advocated negotiations with the Soviet Union for mutual withdrawal of forces from Germany. He got little support within the Eisenhower and Truman administrations.
But the scholar-diplomat also urged the American government to "withdraw from its public advocacy of democracy and human rights" - a position that would not sit well with the Bush administration today. And Ambassador Averell Harriman once said that Kennan understood Russia better than he did the United States.
Kennan wrote that Americans, especially Californians, were "childlike in many respects, fun-loving ... unanalytical, un-intellectual ... preoccupied with physical beauty and prowess ... given to sudden unthinking seizures of aggressiveness."
Yet, it is hard to think of America and the world today without the profound effect that Kennan had on averting a hot and possibly nuclear war instead of a half-century of cold war, that ended as he predicted it would.
• Daniel Schorr is the senior news analyst at National Public Radio.