Although the Soviet Union and the United States had been allies in World War II, disagreements over the organization of the postwar world led the two countries to compete militarily and politically through the next several decades. In the 1950s this competition was particularly intense, resulting in the Cold War and in regional proxy wars. The U.S. perceived Soviet support for the spread of communism as a strong threat, and American foreign policy attempted to contain and thwart communism around the world. U.S. foreign policy during the 1950s was shaped largely in response to perceived threats from the Soviet Union; U.S. participation in the Korean War and American response to the launch of Sputnik illustrate the Soviet influence on U.S. foreign policy.The Korean War was the result of the division of Korea into communist North and capitalist South. When the North invaded the South, the US saw it as a bold communist effort at expansion. Compounding the United State’s fears, the attack was endorsed by the USSR, and partially lead by Red China. The US feared that communism would spread throughout South East Asia should the communist forces takeover the whole of Korea. This would thus allow them to be able to strike any where in Asia or the Pacific. In response, the US sent her own forces in to oppose those of the North Korean communists, and later the Chinese forces. In effect, the Korean War was a proxy war between the main communist and capitalist forces. The Korean War helped further shape the US policy of containment towards the Soviet Union and other communist forces. This is evident in General MacArthur’s pleas to President Truman to expand the war into mainland China, which Truman denied and subsequently led to MacArthur’s dismissal. Thus the US participation in the Korean War showed the United State’s policy of containment towards the Soviet Union, which was in turn used in regard to other communist n...