From a reader:

Dear Jonah:
I loved Liberal Fascism!
After reading it, I thought of something else that supports what you are contending – East Germany.
If Fascism and Communism were polar opposites, then how could East Germany adopt Communism with such ease?
I don’t know if this is something you’ve addressed or not, but I think the reality of the East German state supports your contention.
I look forward to your next book.