sentences:  It echoed the "quarantine the aggressor" policy Truman's predecessor, Franklin D. Roosevelt, had sought to impose to contain German and Japanese expansion in 1937 ("quarantine" suggested the role of public health officials handling an infectious disease).The medical metaphor extended beyond the immediate aims of the Truman Doctrine in that the imagery combined with fire and flood imagery evocative of disaster provided the United States with an easy transition to direct military confrontation in later years with the Korean War and the Vietnam War.By framing ideological differences in life or death terms, Truman was able to garner support for this communism-containing policy.