Several recent books have argued that comparative case studies of crises demonstrate the failure of rational-deterrence theory; they have offered certain empirical generalizations as substitutes. This paper shows that such contentions are unwarranted. First, the empirical generalizations are impressive as historical insights, but they do not meet the standards for theory set out by the most sophisticated case-study analysts themselves. Second, the “tests” of rational deterrence used in the case studies violate standard principles of inference, and the ensuing procedures are so biased as to be useless. Rational deterrence, then, is a more successful theory than portrayed in this literature, and it remains the only intellectually powerful alternative available.
Case studies are essential to theory building: more efficiently than any other methods, they find suitable variables, suggest middle-range generalizations for theory to explain, and provide the prior knowledge that statistical tests require. Their loose constraints on admissible propositions and suitable evidence are appropriate and even necessary for these tasks. These same characteristics, however, inevitably undermine all attempts to construe case-study generalizations as bodies of theory or tests of hypotheses.