Summary

The pattern of international conflict and peace differs from region to region. Regions differ from each other not only in terms of the simple presence or absence of war but also the degree to which war or any sort of military conflict is likely in the long run. Arguments have been offered to explain the spatial heterogeneity in war and peace. One approach to explaining regional peace is additive—the peacefulness of international politics is essentially analyzed and explained at either monadic or dyadic level variation. Notably, the dyadic approach to international conflict and peace has been dominant in the contemporary international relations. For example, two states that are economically dependent, both democratic, with vastly different levels of capabilities, and involved in neither a territorial dispute nor rivalry are likely to develop peaceful relationships. From this perspective, the regional degree of peace is explained by summing up the peacefulness of dyads within a region.

Although this approach to regional peace has been dominant in the field, other approaches go beyond this simple additive approach. The first such explanations base their theoretical arguments on dyadic or monadic mechanisms, but focus on regionwide conditions such as consistency between national and state borders. Regional conflict and peace are ultimately explained by these regional historical conditions. The second group of explanations draw on the notion of spatial contagion through such mechanisms as domestic instability and war expansion in which international and civil wars provide opportunities for further conflict in the neighborhood in various ways. Conflict diffuses through spatial contagion and war joining, which in turn produces a zone of conflict. The third strand of explanations involve more explicit analyses of interdependence between units—states or dyads—which does not necessarily have to take place in the spatial context but often so. For example, pacifying international trade may result from “flying geese” learning and socialization processes within a neighborhood, thus making a whole region peaceful. Furthermore, studies that draw on techniques of network analysis tend to directly model dyad-to-dyad interdependence as an important source of conflict and peace. In short, there are various approaches to explain the regional variation of international conflict and peace from both additive monadic or dyadic approaches and more complex approaches that assume regional clustering of material conditions and interdependence between micro-units in space.