Why Didn't the United States Join The League Of Nations?
Threat to Sovereignty
The Covenant of the League of Nations was part of the Treaty of Versailles. Article X of the Covenant of the League Nation dealt with collective security. The League of Nations sought to use the collective military resources of its member nations to resist any aggression. This meant that joining the League would make it necessary for the United States to engage in war, even when Congress would not be in favor of an armed conflict.
Growth of Isolationism
The Republican Party actively promoted a “return to normalcy” campaign for the 1920 presidential election. This campaign pitted the Republican candidate, Warren G. Harding, against Democrat James M. Cox, who inherited President Wilson’s legacy of support for the League of Nations. Harding took advantage of the isolationistic sentiments prevalent at the time and won a resounding victory. This negated any chance the United States had at joining the league.
The Monroe Doctrine
A lobby of Congressmen opposed joining the League of Nations since it went against the Monroe Doctrine. The Monroe Doctrine, introduced on December 2, 1823, stipulated that all future attempts of the European nations to colonize would be considered acts of hostility and would invite U.S. military intervention. Ratifying the Treaty of Versailles would have been contrary to the Monroe Doctrine.
The League of Nations had its origins in the ideas of President Woodrow Wilson, and the president had undertaken a massive campaign to secure support for the Treaty of Versailles, but Congress did not ratify the treaty. The United States did not join the League of Nations, seriously undermining the organization’s efficacy.