The âtheoryâ of preventive war predicts that states are most likely to undertake military action in response to a rising challenger if they expect that the adversary will surpass them in military strength and then engage in hostile behavior, so that a future war with the challenger is likely. The biggest apparent anomaly for this theory is the Western rejection of a strategy of prevention based on better-now-than-later logic in favor of the strategy of appeasement in the 1930s. In our previous work on the Rhineland Crisis of 1936 and the Czechoslovak Crisis of 1938, we demonstrated that the British and French non-response is not at odds with preventive war theory because British leaders believed that the transition had already occurred prior to 1936, leaving France and Britain with few options, and because French leaders would not take a firm stand against Germany without British support. This interpretation begs the question of why Britain and France did not respond more firmly to the rise of Hitler and to German rearmament before 1936, either through military buildups of their own, a containment strategy based on alliances, or perhaps through coercive threats or preventive military action. In this paper, we address this important question with an analysis of British and French government documents and private papers. We conclude with a discussion of the limits of preventive war theory. ..PAT.-Unpublished Manuscript [ABSTRACT FROM AUTHOR]