Came across this clip from the old film "The Great Dictator" starring Charlie Chaplin. The movie was released in 1940 and was written and produced by Chaplin as well. At the time the movie debuted, the United States was still formally at peace with Germany. The film delivers a scathing rebuke of Adolf Hitler and the Nazi movement.
Enjoy this scene where Chaplin delivers a rather rousing speech:
(H/T to Deborah E.)