"You say that a question [is] asked as to why the Germans did not use gas in World War II. There were, I think, three reasons: 1) that one side had a plentiful supply of gas; 2) that World War I had proved gas to be not a decisive weapon; 3) that gas masks had made gas much more ineffective than it was in World War I. Only the first of these three reasons has any analogy with the possible use of nuclear weapons in World War III."