The causes and effects of the use of force raise crucial questions of substance and method. Issues are multiple and often are confused with each other. Thus, while many case-study findings contradict “second-wave” deterrence theory, they are consistent with some rational deterrence theories. Many findings, however, cannot be squared with the assumptions of rationality. Policies are suboptimal and behavior is often inconsistent. Furthermore, the actor's values, beliefs, and calculations are exogenous to rational theories and can only be supplied by empirical analysis.