What if FDR had given political assylum to Trotskij and he had survived World War 2 in America. Could we see him as some anti-Stalin Trumphcard for the United States in early Cold War??
It could lead to a very interesting scenario of the US socialist left turning Trotskyist due to a more prolongued and direct influence by Trotsky. If that were to happen, then being a socialist in the United States might be half-way respectable, since Trotskyists tend to be very Pro-US during the Cold War
I think for the US to Trotsky asylum there would have to be a greater anti-stalin feeling in the US. I don't think that the US would necessarily need to be socialist to accept Trotsky. If you divorce politics from the situation Trotsky could be supremely useful to the US.