The causal logic behind many arguments in historical institutionalism emphasizes the enduring impact of choices made during critical junctures in history. These choices close off alternative options and lead to the establishment of institutions that generate self-reinforcing path-dependent processes. Despite the theoretical and practical importance of critical junctures, however, analyses of path dependence often devote little attention to them. The article reconstructs the concept of critical junctures, delimits its range of application, and provides methodological guidance for its use in historical institutional analyses. Contingency is the key characteristic of critical junctures, and counterfactual reasoning and narrative methods are necessary to analyze contingent factors and their impact. Finally, the authors address specific issues relevant to both cross-sectional and longitudinal comparisons of critical junctures.

Despite substantial evidence that international trade has promoted peace in the post—World War II era, the commercial peace research program still faces an important historical challenge. Dramatic economic integration in the nineteenth century failed to prevent the increasing interstate hostilities that culminated in the outbreak of war in 1914. This article uses a theoretical revision grounded in standard trade theory to reexamine the relationship between commerce and peace in the fifty years before World War I, a period often referred to as the first era of globalization. The article focuses on domestic conflict over commercial policy rather than on interdependence to understand the conditions under which globalization promotes peace. In a sample dating from 1865 to 1914, the authors find that lower regulatory barriers to commerce reduce participation in militarized interstate disputes. Contradicting conventional wisdom, this evidence affirms a basic premise of commercial liberalism during the first era of globalization—free trade promotes peace.

Democracy promotion has been an explicit doctrine of U.S. foreign policy since the end of the cold war. Between 1990 and 2003 resources for democracy programs increased by over 500 percent. Has this policy worked? Prior research has been inconclusive, relying either on case studies or on quantitative efforts that have not distinguished overall foreign assistance from democracy promotion. The authors answer this question using a new data set that includes program information for 165 countries for the years 1990–2003. The analysis distinguishes between direct and indirect causal mechanisms and employs a variety of statistical models that allow the authors to control for the unique democratization trend in each country when assessing causal effects, as well as for the potential endogeneity of U.S. democracy assistance. The analysis shows that democracy assistance does indeed have a significant impact.

Drawing on historical and rational choice institutionalism, this article seeks to explain the evolution of the Workers' Party as it moved from opposition to government between 1989 and 2002. The Partido dos Trabalhadores (PT), a once radical and programmatic party, came to look more like its catchall competitors over time. This shift resulted from the heightened emphasis placed on immediate vote maximization after Brazil's adoption of market reforms rendered the party's socialist project unviable. Vote maximization made the PT more susceptible to the institutional incentives for building electoral and political support in Brazil, incentives that induce parties to weaken their programmatic positions, forge opportunistic alliances, and resort to patronage and even corruption. To grow, the PT ended up applying such tactics, which it had long condemned. Yet its adaptation was incomplete and uneven due to historical legacies that hindered change. The analysis thus suggests that institutions evolve in response to changing environmental conditions but in ways constrained by past trajectories.

Comparative research on the determinants of genocide has surged in recent years, as reflected in the six books under review. The new research makes genocide studies more systematic and theoretical; integrates the topic into mainstream social science disciplines; points to three emerging explanatory paradigms; and yields some surprising cumulative findings. However, the works also reveal significant conceptual, empirical, and methodological problems that limit the comparative enterprise and the search for a general theory. The article argues for an alternative, disaggregated approach that situates genocide within a spectrum of organized violence against civilians and links genocide studies to studies of violence in war.