The League of Nations was formed in 1919 at the Paris Peace Conference, just after the horrors of World War I. It had initial, near-fatal flaws. One was that the United States never joined, although President Woodrow Wilson was a strong advocate of the League. Also, too, initially Russia and Germany (who lost in World War I) were not permitted into it. Japan and Italy left the League of Nations in the 1930s. It had been believed the great powers -- Great Britain, Russia, Germany, France and Japan -- would act as enforcers.