The United States' foreign policy toward the Soviet Union during the Cold War was based on many principles and factors. The conflicting ideologies of a democracy and that of a totalitarian socialist regime were chief among them.
After the end of World War II, the United States and the Soviet Union emerged as the two strongest and most influential world powers. Both had fought hard to topple fascist Germany. However, as early as 1945, the Soviet Union seemed poised to merely replace Germany as the dominant political and imperialistic force in Europe and elsewhere. The United States sought to preserve the status quo of independent and democratic nations. This put the two nations at odds.
The United States favored a new world order in which democratic nations emerging out of the ashes of the war could settle their differences peacefully through international agencies. This would hopefully prevent another large war. This put the country further at odds with the Soviet Union, which sought to spread communism through direct takeovers and other heavy-handed tactics.
Starting soon after the war, the United States began a policy of containment. The country sought to stop the spread of communism by the Soviet Union under the Truman Doctrine. This policy defined the conflict of the Cold War as a struggle between free democracies and totalitarian regimes. As a result, whenever Soviet influence was detected abroad, such as in the case of Greece in 1947, the United States stepped in to counter this threat through the promotion of democratic government.
The practice of containing the spread of communism was practiced throughout the Cold War. The United States openly and secretly supported anti-communist movements around the world. Furthermore, when politically expedient, the United States aided democratic movements in nations it perceived as possibly vulnerable to the influence of the Soviet Union.