<P> The U.S. initially refused to recognize the Soviet Union, but President Franklin D. Roosevelt reversed the policy in 1933 in the hope to expand American export markets . </P> <P> The Munich Agreement of 1938 was a failed attempt to contain Nazi expansion in Europe . The U.S. tried to contain Japanese expansion in Asia in 1937 to 1941, and Japan reacted with its attack on Pearl Harbor . </P> <P> After Germany invaded the Soviet Union in 1941 during World War II, the U.S. and the Soviet Union found themselves allied against Germany and used rollback to defeat the Axis Powers: Germany, Italy, and Japan . </P> <P> Key State Department personnel grew increasingly frustrated with and suspicious of the Soviets as the war drew to a close . Averell Harriman, U.S. Ambassador in Moscow, once a "confirmed optimist" regarding U.S. - Soviet relations, was disillusioned by what he saw as the Soviet betrayal of the 1944 Warsaw Uprising as well as by violations of the February 1945 Yalta Agreement concerning Poland . Harriman would later have a significant influence in forming Truman's views on the Soviet Union . </P>

Containment designed to prevent the expansion of soviet influence was