76 International Organization evidence consistent with its argument,the conceptual difficulties are formidable. First,when is a state hegemonic?While it may not be necessary to posit possession of some precise share of world capabilities as a threshold for qualification as a hegemonic state,at least one ought to be as explicit as possible about the distributions of capability associated with hegemony,near- hegemony,and nonhegemony.For instance,what are we to make of the periods 1815-1849 and 1880-1914 in the light of Krasner's and Gilpin's comments?If the defeat of France,the settlement of Vienna,and undisputed British naval superiority really were the key ingredients in the establishment of British hegemony,why does Gilpin date the peak of that hegemony as beginning only in 1849?Similarly,if-as Krasner argues-Britain was not yet at the peak of her hegemony when she allegedly secured the opening of the trading system in the early 1860s,are we then to conclude that near- hegemonic states can achieve the same sorts of successes as truly hegemonic states?If so,how can we reconcile British success in the near-hegemonic period of the 1860s with British failure to maintain an open system in the near-hegemonic period of the 1880s? Related to this difficulty is the silence of hegemonic stability theory on the motivations and capabilities of the nonhegemonic states that are most likely to rival the hegemonic power.It might be the case that states that are nearly as efficient and technologically advanced as the hegemonic state exhibit nearly as strong a preference for an open trading system as the hegemonic leader.If that were true,then conflict over a desired trading system would be slight and little inducement would be required to achieve these states' assent to an open trading system.However,if potential rivals to the hegemonic state are less optimistic about their abilities to catch up to the hegemonic state,they may conclude that their interests are not served by an open trading system.In such a case the states that oppose an open system might well coalesce against the hegemonic state and its favored policy.If this were to occur,the capabilities required to maintain an open system would be much greater than under the first contingency;a level of capability sufficient to maintain hegemony in the first instance could well prove insufficient in the second. A third conceptual difficulty is even more serious.In what sense is heg- emonic stability theory about "power"?Gilpin's consideration of the im- portance of power rests on his general observation about the superiority of the Royal Navy,but he conveys no sense of how this military advantage translated into Britain's desired policy outcome.Krasner does provide some concrete examples of the role of military power in changing the tariff policies of states in Latin America and in securing regions of Africa for the British (He could have added the imposition of low tariffs on Turkey and China, an effort that engaged Britain and other Western states as well.)However, if hegemonic stability theory's only prediction were that a dominant European76 International Organization evidence consistent with its argument, the conceptual difficulties are formidable. First, when is a state hegemonic? While it may not be necessary to posit possession of some precise share of world capabilities as a threshold for qualification as a hegemonic state, at least one ought to be as explicit as possible about the distributions of capability associated with hegemony, near￾hegemony, and nonhegemony. For instance, what are we to make of the periods 18 15-1 849 and 1880-19 14 in the light of Krasner's and Gilpin's comments? If the defeat of France, the settlement of Vienna, and undisputed British naval superiority really were the key ingredients in the establishment of British hegemony, why does Gilpin date the peak of that hegemony as beginning only in 1849? Similarly, if-as Krasner argues-Britain was not yet at the peak of her hegemony when she allegedly secured the opening of the trading system in the early 1860s, are we then to conclude that near￾hegemonic states can achieve the same sorts of successes as truly hegemonic states? If so, how can we reconcile British success in the near-hegemonic period of the 1860s with British failure to maintain an open system in the near-hegemonic period of the 1880s? Related to this difficulty is the silence of hegemonic stability theory on the motivations and capabilities of the nonhegemonic states that are most likely to rival the hegemonic power. It might be the case that states that are nearly as efficient and technologically advanced as the hegemonic state exhibit nearly as strong a preference for an open trading system as the hegemonic leader. If that were true, then conflict over a desired trading system would be slight and little inducement would be required to achieve these states' assent to an open trading system. However, if potential rivals to the hegemonic state are less optimistic about their abilities to catch up to the hegemonic state, they may conclude that their interests are not served by an open trading system. In such a case the states that oppose an open system might well coalesce against the hegemonic state and its favored policy. If this were to occur, the capabilities required to maintain an open system would be much greater than under the first contingency; a level of capability sufficient to maintain hegemony in the first instance could well prove insufficient in the second. A third conceptual difficulty is even more serious. In what sense is heg￾emonic stability theory about "power''? Gilpin's consideration of the im￾portance of power rests on his general observation about the superiority of the Royal Navy, but he conveys no sense of how this military advantage translated into Britain's desired policy outcome. Krasner does provide some concrete examples of the role of military power in changing the tariff policies of states in Latin America and in securing regions of Africa for the British. (He could have added the imposition of low tariffs on Turkey and China, an effort that engaged Britain and other Western states as well.) However, if hegemonic stability theory's only prediction were that a dominant European