Geography and weapons technology form an important context in which interstate, intrastate, and extra-state conflicts occur. In this chapter we explore how geography and weapons technology affect the territory controlled by armed rivals and the risk of violence between them. We begin with Boulding's (1962) spatial model of intergroup rivalry, which highlights geographical and technological dimensions of conflict such as spheres of influence, offensive and defensive technologies, and strategic depth. We then summarize O'Sullivan's (1991) three-dimensional extension of Boulding's model. We turn to the Lanchester (1916) model of war attrition to illustrate how combinations of geography and weapons technologies create incentives for nations or groups to go on the offensive, or stay on the defensive, in violent encounters. We also present Alesina and Spolaore's (2003) theory of the number and size of nations in the international system. Selected empirical studies related to the geography and technology of conflict are summarized.

Boulding's Model of Spatial Conflict

Basic Model

In his classic work Conflict and Defense: A General Theory, Boulding (1962) modeled conflict over territory among states or non-state groups by adapting prior economic theory on spatial competition. The basic model is shown in Figure 9.1, where two players A and B have home bases located at points A and B in a geographic space represented by line L1L2. A player's home base might be its capital if the player is a state, or a jungle or mountainous hideout if the player is a rebel or terrorist organization.

For millennia, philosophers and sages have pondered the origins and horrors of war. Despite this long history of inquiry, it is only in the last century that scholars from political science, economics, and other disciplines have attempted to use the quantitative methods of social science to study the causes and effects of war. Building on the early work of Lewis Richardson, Pitirim Sorokin, and Quincy Wright, the social scientific study of war was well established by the mid-1960s around a community of scholars associated with the Correlates of War Project, the Peace Science Society (originally, Peace Research Society), the Journal of Conflict Resolution, and the like. Since then, a wealth of social scientific studies of war has appeared in journals and books across the various disciplines (Singer 2000, Anderton and Carter 2007). In this chapter we focus on armed conflict between states, before we turn to civil war in Chapter 7.

The Conflict Cycle

Conflicts typically pass through phases, as shown by Lund's (1996) life-cycle diagram in Figure 6.1, which plots the level of conflict between parties across time. The conflict in question may be interstate as covered in this chapter, intrastate as in Chapter 7, or extra-state as in Chapter 8. The bell-shaped curve represents the course of a typical conflict as hostility rises and falls over time. The vertical axis marks levels of conflict beginning with durable peace and rising successively to stable peace, unstable peace, crisis, and war.