What was the American policy of containment of the USSR?

At the end of World War II, Soviet troops occupied the nations of Eastern Europe, including Poland, eastern Germany, Czechoslovakia, Hungary, and Romania. Although the United States government believed that these nations should be allowed to decide their own political future, the U.S. was unwilling to continue fighting a war in order to force the Soviets to withdraw their armies from Eastern Europe.

In February 1945, at a diplomatic conference in the Russian town of Yalta, U.S. President Franklin D. Roosevelt and British Prime Minister Winston Churchill conceded control of Eastern Europe to the USSR. Soviet leader Josef Stalin had a very different view of the issue. Because the Soviet Union had suffered some 20 million casualties during the war, and because Russia feared a possible invasion from the west, Stalin believed that the USSR needed a buffer zone to separate and protect Russia's western border. Disagreement over the fate of the nations of Eastern Europe was one major source of the Cold War. In 1946, Churchill referred to the divide between communist and non-communist Europe as an Iron Curtain.

In 1946, George Kennan, an American diplomat in Russia who was considered among the most expert observers of the USSR, wrote the Long Telegram, a message to the State Department containing suggestions about policy toward the USSR. The following year, Kennan wrote an article in the influential journal Foreign Affairs, about the Soviet Union. Kennan argued that the United States should adopt a policy of containment, preventing the USSR from gaining more territory or influence (especially in Europe or Japan), but should not attempt to confront the Soviet Union directly. Kennan believed that the U.S. had a superior political system and economy, and predicted that the Soviet Union would eventually crumble. (He suggested that the USSR might last another thirty years). Russian diplomats took the opposite view, believing that the United States, not the Soviet Union, was doomed to fail, and accused the U.S. of trying to destroy the USSR.