The United Nations was officially created when its charter was signed on June 26, 1945, by 51 countries, including the United States. The new international organization was the successor of the League of Nations, which had been formed by U.S. president Woodrow Wilson at the end of World War I in an attempt to prevent the kind of military aggression that might lead to future global conflicts. Unfortunately, the League had proved to be ineffective early on. Both Japan and Germany had withdrawn from the organization in the early 1930s and had later become the aggressors in World War II. Throughout 1943 and 1944, representatives from the United States, the Soviet Union, the United Kingdom, and China—allies during World War II—had met to discuss the formation of an international organization that would replace the League of Nations. At the end of the war, this organization—the United...