The Cold War was the most important political issue of the early postwar period. It grew out of longstanding disagreements between the Soviet Union and the United States. In 1918 American troops participated in the Allied intervention in Russia on behalf of anti-Bolshevik forces. American diplomatic recognition of the Bolshevik regime did not come until 1933. Even then, suspicions persisted. During World War II, however, the two countries found themselves allied and thus ignored their differences to counter the Nazi threat.  

At the war's end, antagonisms surfaced again. The United States hoped to share with other countries its conception of liberty, equality and democracy. With the rest of the world in turmoil, struggling with civil wars and disintegrating empires, the nation hoped to provide the stability to make peaceful reconstruction possible. Unable to forget the specter of the Great Depression (1929-1940), America now fostered its familiar position of free trade, and sought to eliminate trade barriers both to create markets for American agricultural and industrial products, and to ensure the ability of West European nations to export as a means to generate economic growth and rebuild their economies. Reduced trade barriers, it was believed, would promote economic growth at home and abroad, and bolster stability with U.S. friends and allies.  

The Soviet Union had its own agenda. The Russian historical tradition of centralized, autocratic government contrasted with the American emphasis on democracy. Marxist-Leninist ideology had been downplayed during the war but still guided Soviet policy. Devastated by the struggle in which 20 million Soviet citizens had died, the Soviet Union was intent on rebuilding and on protecting itself from another such terrible conflict. The Soviets were particularly concerned about another invasion of their territory from the west. Having repelled Hitler's thrust, they were determined to preclude another such attack. The Soviet Union now demanded "defensible" borders and regimes sympathetic to its aims in Eastern Europe. But the United States had declared the restoration of independence and self-government to Poland, Czechoslovakia and the other countries of Central and Eastern Europe one of its war aims.