The Cold War has been described by historians as the struggle between communism, led by the Soviet Union, and the free market systems of Europe and the United States, fought with propaganda, rising military budgets, wars by proxy, covert activities, and the political use of military and economic aid.
During World War II, despite mutual suspicion and distrust, the United States and Great Britain joined the Soviet Union in an effort to defeat their common enemy, Nazi Germany. The alliance began to crumble immediately after the surrender of the Hitler government in May 1945. Tensions were apparent during the Potsdam Conference in July, where the victorious Allies created the joint occupation of Germany. Determined to have a buffer zone between its borders and Western Europe, the Soviet Union set up pro-communist regimes in Poland, Hungary, Bulgaria, Czechoslovakia, Romania, Albania and eventually in East Germany. Recognizing that it would not be possible to force the Soviets out of Eastern Europe, the United States developed the policy of containment to prevent the spread of Soviet and communist influence and power in Western European nations such as France, Italy and Greece.
These events and decisions marked the beginning of the Cold War, a struggle between communism and the free market systems of Europe and the United States, fought with propaganda, rising military budgets, wars by proxy, covert activities and the political use of military and economic aid. During the decade of the 1940s, the United States reversed its traditional reluctance to become involved in European affairs. The Truman Doctrine (1947) pledged aid to governments threatened by communist subversion. The Marshall Plan (1947) provided billions of dollars in economic assistance to eliminate the political instability that could result in communist takeovers of democratically elected governments. When the Soviets cut off all road and rail traffic to the divided city of Berlin (1948), the United States and Great Britain responded with a massive airlift that supplied the besieged city for 231 days until the blockade was lifted. In 1949, the United States joined the North Atlantic Treaty Organization, the first mutual security/military alliance in American history.
During the next decade, with the European situation essentially frozen in place, the conflict between East and West took place mainly in Asia, Africa and Latin America. The struggle to overthrow colonial regimes frequently became entangled in Cold War tensions as the superpowers competed to influence and control anti-colonial movements. In 1949, the communists triumphed in the Chinese civil war, setting off a bitter political debate in the United States concerning "who lost China." In 1950, after North Korea invaded South Korea, the United Nations and the United States sent military forces. When Communist China also intervened, several years of bloody campaigns were fought until a truce was signed in 1953 ending the Korean War.
After the defeat of the colonial French regime in Vietnam (1954), the United States supported a military government in South Vietnam and worked to prevent free elections which might result in the unification of the country under the control of communist North Vietnam. President Eisenhower also approved sending several thousand U.S. military advisers to help train the South Vietnamese army.
Closer to home, the Cuban resistance movement led by Fidel Castro deposed the pro-American military dictatorship in 1959. Castro's Cuba quickly became militarily and economically dependent on the Soviet Union. In early 1961, the Eisenhower administration broke diplomatic relations with Cuba, tacitly acknowledging the presence of a Soviet foothold just ninety miles off the coast of Florida.
The 1960 presidential campaign was dominated by Cold War rhetoric. Senator John F. Kennedy and Vice President Richard M. Nixon both pledged to strengthen American military forces and both promised a tough stance against the Soviet Union and international communism. Kennedy warned (inaccurately) of a missile gap with the Soviets and pledged to revitalize American nuclear forces. He also criticized the Eisenhower administration for permitting the establishment of a pro-Soviet government in Cuba.