How did the US Senate known as the irreconcilables refuse to approve the Versailles peace treaty?

The US Senate, particularly the group known as the "irreconcilables," opposed the Versailles peace treaty primarily due to concerns over the League of Nations, which they believed could entangle the United States in foreign conflicts and undermine national sovereignty. They argued that joining the League would compromise the US's ability to independently determine its foreign policy. Their staunch resistance, along with other opposition in the Senate, ultimately led to the treaty's rejection in 1920. This reflected broader isolationist sentiments in the post-World War I era.