Dr. Quinlan and I are in fundamental agreement on the validity of nuclear deterrence as a national security strategy because the possibility of nuclear use cannot be ruled out. Where we disagree is on the conceptual basis for formulating such a strategy. Dr. Quinlan finds my minimalist approach to deterrence unsatisfactory because it rests on a very small number of historical cases in which states with large arsenals were deterred by states with far smaller ones. An argument for deterrence working with larger nuclear armouries cannot rest on historical evidence, of course, since there is only one example of such a relationship – the United States and the Soviet Union – and that too for a limited duration from the late 1960s onward.