Since we're all about punching Nazis, I thought we ought to pay homage to one of the greatest comic book covers ever. If punching out Hitler is wrong, Captain America doesn't want to be right.
Said issue, if you're wondering, is pretty much page after page of Nazis getting their asses kicked, Nazis constantly be depicted as the repugnant scum that they are, all this months before the US would actually enter WWII. In addition, the Nazis had a sizeable amount of US support, so the people involved with this comic, faced death threats and bomb threats.
Oh and Joe Simon and Jack Kirby? Both of them were Jewish, both had family in Europe who would lose their lives in the Holocaust, and when the US entered the war, they enlisted and did their part.