The United States took a major role in every part of wartime operations and postwar peace negotiations. At the Tehran, Yalta, and Potsdam Conferences (more on these when we get to the Cold War), Presidents FDR and Truman represented the United States. Due to its major role in defeating the Axis Powers, the level of wartime destruction in Asia and Europe, and the U.S. willingness to provide help to those who needed it, the United States emerged from World War II as a superpower, one of the two most powerful countries in the world. (The Soviet Union was the other one.)