By design, the deterrence models explored in part II are extremely austere. To be sure, the “no-fat” modeling approach we adopt allows us to focus directly on the role of uncertainty and credibility in both mutual and unilateral deterrence games. But axiomatic austerity cuts both ways. The ability to penetrate core theoretical structures and analyze the role of a few fundamental variables is not altogether costless. Parsimony is inversely related to the complexity and range of questions that a model can fruitfully address. For example, in the simple models developed in part II, conflict is an all-or-nothing proposition. As a consequence, these models are unable to shed any light on the conditions associated with either limited conflicts or escalation spirals. Nor do our rudimentary models capture well the subtleties of some more complex deterrence situations. Thus, to address these and related limitations, we now begin to complicate, ever so slightly, our bare-bones deterrence models and to explore a number of questions associated specifically with extended deterrence relationships.

In this chapter we begin by describing a generic two-level extended deterrence/escalation model and discuss its characteristics under complete information.