196 International Organization I build on the fundamental insights of the Stolper-Samuelson theorem from inter- national economics to argue that exogenous changes in the costs and risks of interna- tional economic exchange can powerfully affect the economic constraints that under- lie the security behavior of states and that these effects will vary predictably across states with different factor endowments.2 As preliminary evidence,I submit that the theory accords surprisingly well with the experiences of the European great powers in the rapidly expanding world economy prior to World War I and that many of the factors that contributed most to the breakdown of international relations in 1914 follow directly from the changing pattern of economic constraints that the theory predicts.By raising the economic returns that flowed to those resources most critical to military power in Europe prior to World War I,especially labor,the expansion of world trade progressively constrained the abilities of the European powers to mobi- lize these resources for security purposes.The growing difficulties of mobilizing resources raised international tensions and undermined stability by fueling anxieties in each state that it was declining relative to its rivals,which,in turn,generated powerful,systemwide incentives to go to war before one's own position became untenable.The rapid expansion of the world economy thus unleashed its own di- lemma for pre-World War I Europe,for the more Europe prospered from the deepen- ing integration of world markets,the more fragile became the security foundations on which that prosperity ultimately rested. Clearly,the relationship between the international economy and the security poli- tics of states has generated a substantial literature in international relations,from debates between liberals and realists over the consequences of economic interdepen- dence to the economic dynamics underlying internationalhegemony and the rise and fall of great powers.I seek to contribute to this literature in at least four ways.First, by extending a widely accepted theory about the economic consequences of interna- tional trade-the Stolper-Samuelson theorem-to the realm of security,I seek to specify more precisely the causal mechanisms by which a changing world economy affects a state's security.Second,by focusing on the domestic distributional conse- quences of internationaleconomic exchange,I depart from the widespread belief that trade influences security primarily through its effects on aggregate national income (rising levels of trade increase a state's military potential by raising national income; falling levels of trade lower it).This departure enables me to make important and counterintuitive propositions.Contrary to conventional wisdom,I argue that the ex- pansion of trade can impair the military power of some states even as it makes them more prosperous.Third,I offer a new interpretation of the origins of World War I that traces many of its causes to the expansion of the world economy.Finally,by showing how world economic expansion undermined European security,I directly challenge the conventional wisdom that the expansion of trade necessarily and unambiguously enhances the prospects for international peace. I must also stress,however,that my argument is preliminary and that my empirical evidence only demonstrates its plausibility.Nor do I imply that changing economic 2.See Stolper and Samuelson 1941/42;and Rogowski 1987 and 1989.I build on the fundamental insights of the Stolper-Samuelson theorem from inter￾national economicsto argue that exogenous changesin the costs and risks of interna￾tional economic exchange can powerfully affect the economic constraintsthat under￾lie the security behavior of states and that these effects will vary predictably across states with different factor endowments.2 As preliminary evidence, I submit that the theory accords surprisingly well with the experiences of the European great powers in the rapidly expanding world economy prior to World War I and that many of the factors that contributed most to the breakdown of international relations in 1914 follow directly from the changing pattern of economic constraints that the theory predicts. By raising the economic returns that  owed to those resources most critical to military power in Europe prior to World War I, especially labor, the expansion of world trade progressively constrained the abilities of the European powers to mobi￾lize these resources for security purposes. The growing difficulties of mobilizing resources raised international tensions and undermined stability by fueling anxieties in each state that it was declining relative to its rivals, which, in turn, generated powerful, systemwide incentives to go to war before one’s own position became untenable. The rapid expansion of the world economy thus unleashed its own di￾lemma for pre–World War I Europe, for the more Europe prospered from the deepen￾ing integration of world markets, the more fragile became the security foundations on which that prosperity ultimately rested. Clearly, the relationship between the international economy and the security poli￾tics of states has generated a substantial literature in international relations, from debates between liberals and realists over the consequences of economic interdepen￾dence to the economic dynamics underlying internationalhegemony and the rise and fall of great powers. I seek to contribute to this literature in at least four ways. First, by extending a widely accepted theory about the economic consequences of interna￾tional trade—the Stolper-Samuelson theorem—to the realm of security, I seek to specify more precisely the causal mechanisms by which a changing world economy affects a state’s security. Second, by focusing on the domestic distributional conse￾quences of international economic exchange,I depart from the widespread beliefthat trade in uences security primarily through its effects on aggregate national income (rising levels of trade increase a state’s military potential by raising national income; falling levels of trade lower it). This departure enables me to make important and counterintuitive propositions. Contrary to conventional wisdom, I argue that the ex￾pansion of trade can impair the military power of some states even as it makes them more prosperous.Third, I offer a new interpretation of the origins of World War I that traces many of its causes to the expansion of the world economy. Finally, by showing how world economic expansion undermined European security, I directly challenge the conventional wisdom that the expansion of trade necessarily and unambiguously enhancesthe prospects for international peace. I must also stress, however, that my argument is preliminary and that my empirical evidence only demonstrates its plausibility. Nor do I imply that changing economic 2. See Stolper and Samuelson 1941/42; and Rogowski 1987 and 1989. 196 International Organization