From the perspective of warding off nuclear apocolypse being the overriding concern, perhaps the play would have been not to drop the bombs on Japan so we could save them to drop on the USSR. If we had invaded Russia at that point we could perhaps have stopped nuclear proliferation with just one nation having the bomb. And after that point, if anybody else even looks funny at an atom, we invade their country and put all their scientists to the sword.

Or is that not a nice enough solution?