While American forces fought Axis forces across the globe, America was also consumed with winning the war at home during World War 2. With Japanese-Americans sent to internment camps and intelligence agencies maintaining surveillance on German-Americans (and not to mention concern about organized labor), America was in a hyper-vigilant state of internal security. Part of this effort involved domestic propaganda, like this “Appreciate America” poster series distributed from 1942 to 1945:
All 'Appreciate America' images via imgur.
For the flip side of propaganda, check out North Korea's brutal anti-American posters.