The Institutional Origins of Ethnic Violence Evan S. Lieberman and Prerna Singh The theory of ethnic violence we develop in this article highlights the role of the state’s institutionalization of ethnic categories. The institutional focus goes a long way toward incorporating constructivist insights about the origins of ethnicity, which have been largely ignored in broadly comparative scholarly analyses. 1 In particular, we address Rogers Brubaker’s attention to the problem of “groupism”—the tendency to take for granted “discrete bounded groups as the basic constituents of social life, chief pro- tagonists of social conflicts, and fundamental units of social analysis.” 2 This critique applies to virtually all of the recent cross-national scholarship on ethnic civil wars. An important set of studies, for example, focuses on the impact of ethnic diversity, in which the presence of multiple ethnic groups is hypothesized to lead to violence. These studies provide a range of explanations based upon various metrics of diversity, and generally find statistical support for claims that particular configurations of group sizes are good predictors of outbreaks of war. 3 However, other influential studies do not find consistent patterns. 4 Not only are findings sensitive to model specification, but no fully defensible metric of diversity has yet to emerge. While we agree that some diversity is a prerequisite for ethnic conflict, there are so many plausible propositions about which configurations of size and numbers of groups heighten the likelihood of conflict that the statistical findings are not particularly robust. A second strand of scholarship casts ethnic groups as potential challengers to the state. Barbara Walter, for example, claims that a state’s likelihood of using violence is a function of the number of potential future challengers who, in turn, will watch how the state addresses threats from any single group. But ambiguity about groups remains. Although Walter uses the “total number of ethnic groups,” a measure based on entries from the Encyclopedia Britannica, which includes all types of groups, including reli- gious, linguistic, ethnic, or foreign-national, 5 it is extremely unlikely that such counts actually indicate the number of mobilized or salient groups that would be recognized by the state as potential challengers. As an alternative measure, she uses the “ethno- political groups” identified through the Minorities at Risk project. However, and again the author anticipates this critique, there is a great deal of bias in the identification of those groups, who themselves have already been subject to some form of discrimination or repression. Our concern is not the theory itself, which is interesting and plausible, but the notion that the size and number of ethnic challengers exist as exogenous social facts. A third approach, Andreas Wimmer, Lars-Erik Cederman, and Brian Min’s rela- tional and configurational model of ethnic violence, is the most impressive. These scholars go the furthest in providing a plausible political mechanism within a model 1