Introduction

The war diffusion model stressed the spatio-temporal environment within which states operate. It proposed that historical and current environments are crucial to understanding international war. The last three chapters explored one kind of situation where the current environment plays a central role in explaining behavior. States learned from what was happening to their neighbors, and their neighbors put pressure on them to conform. The spatial emphasis of the war diffusion framework found strong support in barrier models. This chapter and the next examine the second focus of the diffusion framework, the relation of the past to the present. How does what individuals or dyads do in the past influence what they will do in the future? Evidence for the spatial dependence of war and other phenomena exists. Does it exist for temporal dependence too? Or, are wars temporally “independent” events as many studies imply?

A more general way to pose the temporal dependence question is to ask about the relevance of history for explaining events. History has already appeared as an important context in this volume. The historical context was crucial in defining a valid military allocation indicator; the definition of overallocation depended on the historical period.