Onset of the Cold War
Soon after World War II, the Soviet Union and its Western allies parted ways as mutual suspicions of the other's intentions and actions flourished. Eager to consolidate influence over a number of countries adjacent to the Soviet Union, Stalin pursued an aggressive policy of intervention in the domestic affairs of these states, provoking strong Western reaction. The United States worked to contain Soviet expansion in this period of international relations that came to be known as the Cold War.
Mindful of the numerous invasions of Russia and the Soviet Union from the West throughout history, Stalin sought to create a buffer zone of subservient East European countries, most of which the Red Army (known as the Soviet army after 1946) had occupied in the course of the war. Taking advantage of its military occupation of these countries, the Soviet Union actively assisted local communist parties in coming to power. By 1948 seven East European countries--Albania, Bulgaria, Czechoslovakia, Hungary, Poland, Romania, and Yugoslavia--had communist governments. The Soviet Union initially maintained control behind the "Iron Curtain" (a phrase coined by Churchill in a 1946 speech) through the use of troops, security police, and the Soviet diplomatic service. Inequitable trade agreements with the East European countries permitted the Soviet Union access to valued resources.
Soviet actions in Eastern Europe generated hostility among the Western states toward their former ally, but they could do nothing to halt consolidation of Soviet authority in that region short of going to war. However, the United States and its allies had greater success in halting Soviet expansion in areas where Soviet influence was more tenuous. British and American diplomatic support for Iran forced the Soviet Union to withdraw its troops from the northeastern part of that country in 1946. Soviet efforts to acquire territory from Turkey and to establish a communist government in Greece were stymied when the United States extended military and economic support to those countries under the Truman Doctrine, a policy articulated by President Harry S. Truman in 1947. Later that year, the United States introduced the Marshall Plan for the economic recovery of other countries of Europe. The Soviet Union forbade the countries it dominated from taking part in the program, and the Marshall Plan contributed to a reduction of Soviet influence in the participating West European nations.
Tensions between the United States and the Soviet Union became especially strained over the issue of Germany. At the Potsdam Conference of July-August 1945, the Allied Powers confirmed their decision to divide Germany and the city of Berlin into zones of occupation (with the eastern sectors placed under Soviet administration) until such time as the Allies would permit Germany to establish a central government. Disagreements between the Soviet Union and the Western Allies soon arose over their respective occupation policies and the matter of reparations. In June 1948, the Soviet Union cut off the West's land access to the American, British, and French sectors of Berlin in retaliation for steps taken by the United States and Britain to unite Germany. Britain and the United States thereupon sponsored an airlift that kept the beleaguered sectors provisioned until the Soviet Union lifted the blockade in May 1949. Following the Berlin blockade, the Western Allies and the Soviet Union divided Germany into two countries, one oriented to the West, the other to the East. The crisis also provided the catalyst for the Western countries in 1949 to form the North Atlantic Treaty Organization (NATO--see Glossary), a collective security system under which conventional armies and nuclear weapons would offset Soviet forces.
While the Soviet Union gained a new satellite nation in the German Democratic Republic (East Germany), it lost its influence in Yugoslavia. The local communists in Yugoslavia had come to power without Soviet assistance, and their leader, Josip Broz Tito, refused to subordinate the country to Stalin's control. Tito's defiance led the Communist Information Bureau (Cominform--founded in 1947 to assume some of the functions of the Comintern, which had been abolished in 1943) to expel the Yugoslav party from the international communist movement in 1948. To avert the rise of other independent leaders, Stalin purged many of the chief communists in other East European states.
In Asia the Chinese communists, headed by Mao Zedong and assisted by the Soviet Union, achieved victory over the Guomindang in 1949. Several months afterward, in 1950, China and the Soviet Union concluded a mutual defense treaty against Japan and the United States. Hard negotiations over concessions and aid between the two communist countries served as an indication that China, with its independent party and enormous population, would not become a Soviet satellite, although for a time Sino-Soviet relations appeared particularly close. Elsewhere in Asia, the Soviet Union pursued a vigorous policy of support for national liberation movements, especially in Malaya and Indochina, which were still colonies of Britain and France, respectively. Thinking that the West would not defend the Republic of Korea (South Korea), Stalin allowed or encouraged the Soviet-equipped forces of the Democratic People's Republic of Korea (North Korea) to invade South Korea in 1950. But forces from the United States and other members of the United Nations came to the aid of South Korea, leading China to intervene militarily on behalf of North Korea, probably at Soviet instigation. Although the Soviet Union avoided direct participation in the conflict, the Korean War (1950-53) motivated the United States to strengthen its military capability and to conclude a peace treaty and security pact with Japan. Chinese participation in the war also strengthened China's independent position relative to the Soviet Union.