Concept
Version 12
Created by Boundless
Postwar Isolationism
Source
Boundless vets and curates high-quality, openly licensed content from around the Internet. This particular resource used the following sources:
"United States non-interventionism."
http://en.wikipedia.org/wiki/United_States_non-interventionism%23Non-Interventionism_between_the_World_Wars
Wikipedia
Public domain.