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Wartime conferences
See also: Diplomatic history of World War II
Chiang Kai-shek, Roosevelt, and Winston Churchill at the Cairo ConferenceChurchill, Roosevelt, and Stalin at the Yalta Conference, February 1945, two months before Roosevelt's death
Roosevelt coined the term "Four Policemen" to refer to the "Big Four" Allied powers of World War II, the United States, the United Kingdom, the Soviet Union, and China. The "Big Three" of Roosevelt, Winston Churchill, and Soviet leader Joseph Stalin, together with Chinese Generalissimo Chiang Kai-shek, cooperated informally on a plan in which American and British troops concentrated in the West; Soviet troops fought on the Eastern front; and Chinese, British and American troops fought in Asia and the Pacific. The United States also continued to send aid via the Lend-Lease program to the Soviet Union and other countries. The Allies formulated strategy in a series of high-profile conferences as well as by contact through diplomatic and military channels.[287] Beginning in May 1942, the Soviets urged an Anglo-American invasion of German-occupied France in order to divert troops from the Eastern front.