The first atomic bomb was used by the United States against Japan at the end of World War Two. Within four years, the Soviet Union had also developed its own version of the bomb. The threat of this development was increased by the fact that the Soviet Union was actively expanding its military influence in Eastern Europe at the time. In response to this problem, the United States adopted a policy for the containment of Soviet expansion. Related to this policy was the strategy of deterrence, which sought to protect the Western nations from the possibilty of nuclear attack by the Soviet Union. The concepts of containment and deterrence were to have a strong influence on Soviet-American relations over the following decades. In order to protect its interests in the region, the United States joined with several Western European nations in 1949 to form the North Atlantic Treaty Organization (NATO). In 1955, the Soviet Union formed a similar alliance among the Eastern European nations known as the Warsaw Treaty Organization. The international tensions that arose between these two superpower blocs became known as the "Cold War."
In the struggle to maintain a balance of power, the United States occasionally needed to use its military forces in various parts of the world. This occurred in 1948, for example, when the Soviet Union made an effort to drive the West out of Berlin by imposing a blockade on the city. In reaction to this event, the United States carried out a massive airlift of supplies to the city. Further Cold War tensions erupted in Korea during the early 1950's. At that time, North Korean troops, in collaboration with the Chinese, invaded South Korea. In an effort to prevent the expansion of Communism in Asia, the United States intervened in the situation, thereby giving rise to the Korean Conflict of 1950-53. Another region which was subjected to Cold War activity was the Caribbean Sea. In 1961, the United States...