Originally published in 1985, this book surveys how NATO policy sought to come to terms with the revolution in thinking about war which was brought about by the advent of nuclear weapons. It also examines the logic of deterrence. The book assesses the ethical issues involved, using as a framework the tradition of the idea of the Just War. A detailed modern version of the theory is elaborated and defended from an ethical viewpoint that gives due weight both to the mental states of the agent and to the consequences of his agency. The principle of non-combatant immunity is also examined for its clear relevance to the debate. Further considerations involve the effectiveness of deterrence and its morality, and the question whether deterrence can be effective even if its use is prohibited. The book also discusses the implications of various possible changes in NATO policy.