An international organization established after World War I under the provisions of the Treaty of Versailles. The League, the forerunner of the United Nations, brought about much international cooperation on health, labor problems, refugee affairs, and the like. It was too weak, however, to prevent the great powers from going to war in 1939.
Note: Although President Woodrow Wilson of the United States was a principal founder of the League, the United States Senate refused to ratify the Treaty of Versailles, and the United States never joined the League.