Final answer:
The U.S. Senate never ratified the Treaty of Versailles due to concerns over joining the League of Nations, which they feared could entangle the U.S. in international disputes and undermine congressional war powers. Instead, the U.S. signed a separate peace treaty with Germany and did not join the League.
Step-by-step explanation:
The event that never occurred is the ratification of the Treaty of Versailles by the U.S. Senate. Although President Wilson advocated for the League of Nations and negotiated the Treaty of Versailles to end World War I, the Senate had concerns about the implications of joining the League. They feared it might draw the U.S. into foreign disputes, reduce their power to declare war, and allow other countries to control the League. Ultimately, despite Wilson's intensive efforts, which included a national speaking tour and despite him being a Nobel Peace Prize laureate for his peace efforts, the Senate rejected the Treaty both in its original form and with reservations added later. As a result, the U.S. signed a separate peace treaty with Germany in 1921 and never joined the League of Nations.