There was a substantial population of anti-war activists in the country. “American Firsters” and other non-interventionist groups were well-organized. Then there was the German American Bund. They were all over the place, heavily financed and effective in spewing their propaganda of hate; a fifth column of Americans following the Third Reich party line. They organized pseudo-military training camps such as ‘Camp Siegried’ in Yaphank, Long Island and held huge rallies in such places as Madison Square Garden in New York. Our irreverent treatment of their Feuhrer infuriated them. We were inundated with a torrent of raging hate mail and vicious, obscene telephone calls. The theme was “death to the Jews.” At first we were inclined to laugh off their threats, but then, people in the office reported seeing menacing-looking groups of strange men in front of the building on Forty Second Street and some of the employees were fearful of leaving the office for lunch. Finally, we reported the threats to the police department. The result was a police guard on regular shifts patrolling the halls and office.
No sooner than the men in blue arrived than the woman at the telephone switchboard signaled me excitedly. ‘There’s a man on the phone says he’s Mayor LaGuardia,’ she stammered, ‘He wants to speak to the editor of Captain America Comics.’
I was incredulous as I picked up the phone, but there was no mistaking the shrill voice. ‘You boys over there are doing a good job, ‘ the voice squeaked, ‘The City of New York will see that no harm will come to you.’
— Joe Simon, in “The Comic Book Makers”, on why America First-ers hated to see a Nazi punched and how a Mayor protected Captain America