The U.S. In World War I Questions What were the underlying causes of World War I? What event sparked the beginning of World War I? What was the U.S. policy during the beginning of the war? What did that mean for the U.S.? What were the reasons for U.S. involvement in World War I? How did President Wilson mobilize the country for war? What specific things did he do? What were the 14 Points? What did they propose? What did the Treaty of Versailles do? What were the key terms of the treaty? Why does the U.S. refuse to ratify the treaty and join the League of Nations? What is the League of Nations?