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Why did the United States never join the League of Nations?

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Treaty of Versailles The “Big Four” (left to right): David Lloyd George of Britain, Vittorio Orlando of Italy, Georges Clemenceau of France, and Woodrow Wilson of the United States, the principal architects of the Treaty of Versailles.

The United States never joined the League of Nations primarily due to concerns in the U.S. Senate that membership would compromise American sovereignty and entangle the nation in foreign conflicts.12

Opposition was led by Republican Senator Henry Cabot Lodge, who feared that binding the U.S. to international commitments—specifically the collective security requirements of Article 10—would be fatal to the nation's interests. Lodge proposed a series of reservations to the Treaty of Versailles that would have required congressional approval before the U.S. could be bound by League decisions.13

President Woodrow Wilson refused to accept these amendments, viewing them as a destruction of the League's intent, and insisted on an all-or-nothing strategy. Consequently, the Senate failed to reach the two-thirds majority required by the U.S. Constitution to ratify the treaty, effectively blocking U.S. participation in the League.134