Final answer:
Truman and Stalin both followed policies to prevent the spread of communism and protect their respective countries from external threats.
Step-by-step explanation:
One way Truman and Stalin's approaches to maintaining peace were similar was by both following a policy for stopping the Soviet Union from spreading its influence. Truman's administration recognized that the United States could do little to affect the outcome in Eastern Europe given the postwar agreements between the two nations, so they directed their efforts throughout the rest of the world to prevent communism from spreading beyond the "iron curtain." Similarly, Stalin sought to protect the Soviet Union by establishing Soviet-controlled Communist nations in Eastern Europe as a buffer zone against invasion.