The League of Nations was the first worldwide intergovernmental organization whose principal mission was to maintain world peace. Proposed by U.S. President Woodrow Wilson as part of his 'Fourteen Points,' the League aimed to resolve international disputes through diplomacy and collective security rather than war. However, the League was crippled from the start: the United States Senate refused to join, and the organization lacked an army to enforce its decisions. Throughout the 1930s, the League failed to stop major acts of aggression, such as the Japanese invasion of Manchuria and the Italian invasion of Ethiopia. Its inability to act against the expansionist policies of Germany and Japan ultimately led to its collapse and the outbreak of World War II, though it served as the blueprint for the modern United Nations.