Many Americans opposed the Treaty of Versailles because the provision of joining a League of Nations meant an end to America's pre-war isolationism and an ongoing era of global involvement. In addition, German Americans felt the punitive reparations demanded of Germany were too severe, Italian Americans felt that Italy should have been awarded more territory, and Irish Americans felt that the treaty should have included the independence of Ireland.
In January of 1919, the Paris Peace Conference began. Though 32 nations attended, the conference was dominated by the leaders of the "Big Four," which included the United States,
England, France and Italy. When President Woodrow Wilson returned to present the treaty for ratification, Senator Henry Cabot Lodge vigorously opposed it. Lodge argued that joining the League of Nations would prevent the United States from determining its own affairs. To sabotage the ratification he attached amendments declaring the United States exempt from certain portions. President Wilson insisted that the treaty be adopted in its original form or not at all, and at the Senate vote the Treaty of Versailles failed to get the two-thirds majority required for its passage.
In 1921, the United States signed a separate peace treaty with Germany. Many historians postulate that the ruinous terms of the reparation payments imposed upon Germany in the Treaty of Versailles led to the rise of the Nazi Party and eventually to the Second World