Susan Olzak's new monograph is a milestone in comparative research on ethnic mobilization and conflict. Not only does it chart new theoretical and methodological territory. It also offers the most rigorous proof yet that globalization promotes collective action by ethnic groups. The book's main claim is that transnational networks diffuse “ideologies, strategies, tactics and leaders” rapidly across national borders, enabling ethnic mobilization and “leaving political regimes more vulnerable to internal challenges” (pp. 32, 152). Global processes, in other words, interact with forces at the group and state level to promote violent and nonviolent activism by communal groups.

This “world integration argument” (p. 152) draws on three theoretical perspectives that, together, advance what the author intends as a “unified explanation of ethnic conflict” (p. 100). Her goals are to make sense of the fragmentary findings of a field dominated by case studies; to account for different magnitudes of mobilization (nonviolent as well as violent) across countries and regions; and to capture the diffusion of ethnic mobilization across national boundaries. In a creative synthesis of world system theory, world polity theory, and social movement research (Chapter 1), she constructs a three-level model of ethnic mobilization that includes group- and country-level factors typically found in comparative studies of ethnic conflict: for example, ethnic fractionalization, competition for land, discrimination, poverty, inequality, and formal civil rights. To measure levels of state integration into the global system, she adds variables usually studied only by world systems/world polity scholars: dependency (core/peripheral status) and membership in international nongovernmental organizations (INGOs).

Characteristically, the author puts her argument to a careful empirical test using multiple indicators (group data and event counts) from the Minorities at Risk and Protocol for the Assessment of Nonviolent Direct Action (PANDA) data sets. To tease out causal relationships, she adopts a longitudinal design based on panel analyses across three time periods. This strategy is a major advance over previous large-n studies using cross-sectional data because it permits direct tests of causality. Sensitive to the effects of two-way (simultaneous) causation, the author includes an interesting chapter exploring endogenous models of ethnic violence and protest (Chapter 9).

The combination of robust data and innovative design yields a rich, complex, and sometimes unexpected set of findings. In line with earlier research, Olzak finds that ethnic protest and violence have declined since the early 1990s, particularly in wealthier countries, but that “poverty and embeddedness in a world system of organizations has led to a concentration of violent ethnic activity in a few vulnerable regions” (p. 232). Her results confirm previous studies showing that poverty and economic decline promote ethnic violence; that discriminatory state policies increase both violent and nonviolent action; and that religious pluralism (fractionalization) greatly reduces the magnitude of both. Several unexpected findings challenge emerging “laws” in research on ethnic conflict: for example, the conventional view that democracy encourages ethnic protest but reduces ethnic violence. Olzak finds that democracies in the post–Cold War era have experienced more, not less, ethnic violence than autocracies and semi-authoritarian regimes.

The author's central concern here is to demonstrate the impact of global forces on ethnic mobilization. She uses dynamic modeling to show that countries with the highest number of memberships in INGOs have the highest magnitude of ethnic mobilization and violence, even after controlling for wealth and core/peripheral status; that the impact of INGOs on ethnic mobilization has increased over time (see Tables 6.3 and 7.3); and that peripheral states experienced higher levels of ethnic violence and lower levels of protest than core states did for most of the Cold War era. This cumulative evidence more than sustains the author's claim that global integration promotes and internationalizes ethnic social movements. Less conclusive—because it is inferred, not tested directly—is her constructivist story of the dynamic at work in this process. The story emphasizes the role of INGOs in diffusing “claims for expansion of civil liberties and human rights” around the globe (p. 213), while saying very little about the impact of these organizations in channeling resources to identity groups through “dense information and resource networks” (p. 213). In view of Olzak's many contributions to resource mobilization research, this is a surprising turn, and it ignores the possibility that ethnic groups with a limited commitment to human rights might profit from INGO connections. Ethnic mobilization may not be “inherently destructive” (p. 219), but whether it has a broadly “democratizing, inclusionary” impact (p. 233) is open to debate and further study.

There should be little debate, however, over the value of The Global Dynamics of Racial and Ethnic Mobilization to scholars studying ethnic and identity-based conflict, social movements, and collective action. Because the analysis is complex—multiple models, data sets, and time periods all yielding slightly different results—the narrative thread of the work can be difficult to follow. However, the author's intellectual range, highlighted in a superb literature review in Chapter 2, and the exceptional rigor of her work set a very high standard for future research. Ethnic conflict, as she notes, is a dynamic process, rendered difficult to understand not just because of limitations of method and evidence but also because of its protean nature. This study offers an important synthesis and sorting out of research to date and a persuasive agenda for future research.