After World War 1, prevalent attitudes in America included one of not supporting the US being involved in foreign affairs. World War 1 started in 194 and ended in 1918. After the First World War, isolationism became prevalent in American society. Another attitude that developed was nativism.
here's the website: www.answers.com/Q/What_attitudes_became_prevalent_in_America_after_World_War_
Isolationism became the prevalent attitude of America (Isolationism is the act of not becoming involved in other countries' affairs at all).
