At first, very few supported US entry into the war. It was largely seen as a European problem and not one which presented a threat to the United States. Isolationist ideas still held very strong sway amongst much of the public during this era. The commonly held notion was that the stodgy militarists of the Old World had brought the conflict upon themselves and that America had nothing to gain by joining the bloodletting.

The Zimmerman Telegram led many Americans to change their minds. Although resistance to sending US troops to Europe remained widespread even after the incident, enough citizens and politicians had become convinced that Germany represented a threat. Years of British propaganda about the "Huns" and their alleged brutality had also taken some effect by this time.