The decades following the end of the Cold War have witnessed the growing proliferation of international regulatory institutions with overlapping jurisdictions and ambiguous boundaries. Practicing jurists have expressed concern about the effects of this increased fragmentation of international law, but for the most part international legal theorists have tended to dismiss such concerns as unwarranted. Indeed, many regard the resulting competition for influence among institutions as a generative, market-like pluralism that has produced more progress toward integration and democratization than could ever have been achieved through more formal means.In this Article we argue that the problem of fragmentation is more serious than is commonly assumed because it operates to sabotage the evolution of a more democratic and egalitarian international regulatory system and to undermine the reputation of international law for integrity. It is also more resistant to reform. Powerful states labor to maintain and even actively promote fragmentation because it enables them to preserve their dominance in an era in which hierarchy is increasingly viewed as illegitimate, and to opportunistically break the rules without seriously jeopardizing the system they have created.Fragmentation accomplishes this in three ways. First, by creating institutions along narrow, functionalist lines and restricting the scope of multilateral agreements, it limits the opportunities for weaker actors to build the cross-issue coalitions that could potentially increase their bargaining power and influence. Second, the ambiguous boundaries and overlapping authority created by fragmentation dramatically increase the transaction costs that international legal bodies must incur in trying to reintegrate or rationalize the resulting legal order. Third, by suggesting the absence of design and obscuring the role of intentionality, fragmentation frees powerful states from having to assume responsibility for the shortcomings of a global legal system that they themselves have played the major role in creating. The result is a regulatory order that reflects the interests of the powerful that they alone can alter.