In 1940, John Steinbeck answered a letter inquiring whether he was Jewish because certain “extreme reactionary religionists” around the country were saying that Steinbeck's Grapes of Wrath was Jewish propaganda. Steinbeck responded with regret about the prejudice of that time.
I am answering your letter with a good deal of sadness. I am sad for a time when one must know a man's race before his work can be approved or disapproved.
It happens that I am not Jewish and have no Jewish blood but it only happens that way. I find that I do not experience any pride that it is so.
I Do Not Experience Any Pride That It Is So
This letter gives us a glimpse of some of the pre-war attitudes in the United States. Fortunately there were also men of good will who had the courage to resist prejudice.