Answer: Were tired of losing American lives in Europe
Explanation: In general, the United States assisted in both world wars with its military forces, armaments, and, for example, in WWII played an important role in the final victory over the Nazis.
After the First World War, in addition to human losses, the US also faced political extremism, racial and labor issues. The general conclusion was that US involvement in WWI was a mistake and that something like that should not be repeated. Various strategies have even been developed to avoid a possible future war on a global scale, primarily in Europe. The reason for this is the centuries-old tensions of the European peoples, their disagreements and political pretensions, with which the US has had nothing. The result of US intervention and WWI participation is the loss of people and the post-war consequences of broad measures ranging from depression and lack of motivation to economic and political reasons.