Edited by James Scouras

On Assessing the Risk of Nuclear War

While careful analysis of the likelihood and consequences of the failure of nuclear deterrence is not usually undertaken in formulating national security strategy, general perception of the risk of nuclear war has a strong influence on the broad directions of national policy. For example, arguments for both national missile defenses and deep reductions in nuclear forces depend in no small part on judgments that deterrence is unreliable. However, such judgments are usually based on intuition, rather than on a synthesis of the most appropriate analytic methods that can be brought to bear. This work attempts to establish a methodological basis for more rigorously addressing the question: What is the risk of nuclear war? Our goals are to clarify the extent to which this is a researchable question and to explore promising analytic approaches. We focus on four complementary approaches to likelihood assessment: historical case study, elicitation of expert knowledge, probabilistic risk assessment, and the application of complex systems theory. We also evaluate the state of knowledge for assessing both the physical and intangible consequences of nuclear weapons use. Finally, we address the challenge of integrating knowledge derived from such disparate approaches.