Hi, Archy.
I read somewhere in one of the Manhattan Project histories that the production of nuclear weapons was to have been one a day by the first of the year. Teller was pushing hard for fusion weapons even in 1944. Oppenheimer and the other Reds would have been on board like crazy after the Red Army was committed. Japanese could indeed have become "a language spoken only in Hell."
The nuclear weapons program was stopped with VJ day. I suspect that our home grown Reds were not happy with the Worker's Paradise, the Dictatorship of the Proletariat, being the intended target.
I have this vision of atomic bomb hellfire raining on Japan from Russian Tupolov-4 copies of the B-29.