THE PRECEDING discussion of commitments not involving ex post rationality and of the impact of nuclear weapons on coercion is likely to have generated a certain amount of unease. It may have occurred to the careful reader (particularly one who has vivid memories of the late Peter Sellars in Dr. Strangelove's wheelchair) that in the nuclear age, commitment-through-denial-of-choice and commitment-through-irrationality can yield what has become known as a Doomsday Machine. Before dropping from public attention entirely, the notion of a Doomsday Machine received much criticism and little or no serious advocacy. 1 And yet, the model of a Doomsday Machine clearly deserves more careful review and analysis. As a logical construct, it represents a useful tool for thinking about nuclear conflict in an era of mutual assured destruction capabilities. It serves as a description of a situation that may arise and yield extended deterrent power in a MAD world; as a descriptive tool, it may also prove heuristically useful in developing a prescription for deterrence policy.
The essence of a Doomsday Machine, like that of any coercive device that involves commitment-through-denial-of-choice or commitment-through-irrationality, lies in the inability of its owner rationally to control his own actions once his opponent has engaged in some particular provocation. The pain and destruction of the negative sanction are imposed not because either side rationally wills them to