Containment of the Soviet Union became American policy in the postwar years. George Kennan, a top official at the U.S. embassy in Moscow, defined the new approach in the Long Telegram he sent to the State Department in 1946. He extended his analysis in an article under the signature "X" in the prestigious journal Foreign Affairs. Pointing to Russia's traditional sense of insecurity, Kennan argued that the Soviet Union would not soften its stance under any circumstances. Moscow, he wrote, was "committed fanatically to the belief that with the United States there can be no permanent modus vivendi, that it is desirable and necessary that the internal harmony of our society be disrupted." Moscow's pressure to expand its power had to be stopped through "firm and vigilant containment of Russian expansive tendencies. ..."

The first significant application of the containment doctrine came in the Middle East and eastern Mediterranean. In early 1946, the United States demanded, and obtained, a full Soviet withdrawal from Iran, the northern half of which it had occupied during the war. That summer, the United States pointedly supported Turkey against Soviet demands for control of the Turkish straits between the Black Sea and the Mediterranean. In early 1947, American policy crystallized when Britain told the United States that it could no longer afford to support the government of Greece against a strong Communist insurgency.

In a strongly worded speech to Congress, Truman declared, "I believe that it must be the policy of the United States to support free peoples who are resisting attempted subjugation by armed minorities or by outside pressures." Journalists quickly dubbed this statement the "Truman Doctrine." The president asked Congress to provide $400 million for economic and military aid, mostly to Greece but also to Turkey. After an emotional debate that resembled the one between interventionists and isolationists before World War II, the money was appropriated.

Critics from the left later charged that to whip up American support for the policy of containment, Truman overstated the Soviet threat to the United States. In turn, his statements inspired a wave of hysterical anti-Communism throughout the country. Perhaps so. Others, however, would counter that this argument ignores the backlash that likely would have occurred if Greece, Turkey, and other countries had fallen within the Soviet orbit with no opposition from the United States.

Containment also called for extensive economic aid to assist the recovery of war-torn Western Europe. With many of the region's nations economically and politically unstable, the United States feared that local Communist parties, directed by Moscow, would capitalize on their wartime record of resistance to the Nazis and come to power. "The patient is sinking while the doctors deliberate," declared Secretary of State George C. Marshall. In mid-1947 Marshall asked troubled European nations to draw up a program "directed not against any country or doctrine but against hunger, poverty, desperation, and chaos."

In perhaps the most famous photograph in American political history, President Harry Truman holds aloft a newspaper wrongly announcing his defeat by Republican nominee Thomas Dewey in the 1948 presidential election. Truman's come-from-behind victory surprised all political experts that day.
(© Bettmann/CORBIS)

The Soviets participated in the first planning meeting, then departed rather than share economic data and submit to Western controls on the expenditure of the aid. The remaining 16 nations hammered out a request that finally came to $17,000 million for a four-year period. In early 1948 Congress voted to fund the "Marshall Plan," which helped underwrite the economic resurgence of Western Europe. It is generally regarded as one of the most successful foreign policy initiatives in U.S. history.

Postwar Germany was a special problem. It had been divided into U.S., Soviet, British, and French zones of occupation, with the former German capital of Berlin (itself divided into four zones), near the center of the Soviet zone. When the Western powers announced their intention to create a consolidated federal state from their zones, Stalin responded. On June 24, 1948, Soviet forces blockaded Berlin, cutting off all road and rail access from the West.

American leaders feared that losing Berlin would be a prelude to losing Germany and subsequently all of Europe. Therefore, in a successful demonstration of Western resolve known as the Berlin Airlift, Allied air forces took to the sky, flying supplies into Berlin. U.S., French, and British planes delivered nearly 2,250,000 tons of goods, including food and coal. Stalin lifted the blockade after 231 days and 277,264 flights.

By then, Soviet domination of Eastern Europe, and especially the Czech coup, had alarmed the Western Europeans. The result, initiated by the Europeans, was a military alliance to complement economic efforts at containment. The Norwegian historian Geir Lundestad has called it "empire by invitation." In 1949 the United States and 11 other countries established the North Atlantic Treaty Organization (NATO). An attack against one was to be considered an attack against all, to be met by appropriate force. NATO was the first peacetime "entangling alliance" with powers outside the Western hemisphere in American history.

The next year, the United States defined its defense aims clearly. The National Security Council (NSC) -- the forum where the President, Cabinet officers, and other executive branch members consider national security and foreign affairs issues -- undertook a full fledged review of American foreign and defense policy. The resulting document, known as NSC-68, signaled a new direction in American security policy. Based on the assumption that "the Soviet Union was engaged in a fanatical effort to seize control of all governments wherever possible," the document committed America to assist allied nations anywhere in the world that seemed threatened by Soviet aggression. After the start of the Korean War, a reluctant Truman approved the document. The United States proceeded to increase defense spending dramatically.