Sorry if this is a repeat. I exited before I hit reply.
I'm surprised The Abandonment of the Jews by David Wyman has not been mentioned here. I believe it was the first to discuss why the US did not let the Jews in. It is still worth reading and a good basis for further exploration of the subject.
Certainly the Ken Burns documentary is worth watching (and paying for) I haven't seen it yet.
Gentlemen's Agreement isn't about the Holocaust and not germane to the original question.