Time remembered: A dynamic model of interstate interaction

Over time, states form relationships. These relationships, mosaics of past interactions, provide political leaders with information about how states are likely to behave in the future. Although intuitive, this claim holds important implications for the manner in which we construct and evaluate empirically our expectations about interstate behavior. Empirical analyses of interstate relations implicitly assume that the units of analysis are independent. Theories of interstate interaction are often cast in the absence of historical context. In this article we construct a dynamic model of interstate interaction that we believe will assist scholars in empirical and theoretical studies by incorporating a substantively interpretable historical component into their models of interstate relations. Our conceptual model includes both conflictual and cooperative components, and exhibits the basic properties of growth and decay that characterize dyadic relationships. In an empirical exposition, we derive a continuous measure of interstate conflict from the conflictual component of the model. We rely on Oneal and Russett's (1997) analysis of dyadic conflict for the period 1950-1985 as a benchmark, and examine whether the inclusion of our measure of interstate conflict significantly improves our ability to predict militarized conflict. We find empirical support for this hypothesis, indicating that our continuous measure of interstate conflict significantly augments a well-known statistical model of dyadic militarized conflict. Our findings reinforce the assertion that historical processes in interstate relationships represent substantively important elements in models of interstate behavior rather than econometric nuisances.