The initial phase, reported in Nations in Conflict, is a large-scale cross-national multi-equation econometric investigation of the 45 years leading to World War I (Choucri and North, 19751). The quantitative work includes a set modeling and simulations that yield empirical connections between the master variables and the behavior of states. Choucri and North developed an econometric simulation model of six major powers over the span of 45 years leading to World War I. In each case they found the causal connection between the master variables and the overt international behavior. The traditionally dominant power during this period, Great Britain, viewed any significant growth in other powers as a source of threat and these perceptions were translated into specific policies intended to retain an advantage over the other powers, most notably a rapidly growing and newly unified Germany. The discussion of each of the equations in the overall model of jointly estimated dependent variables is contextualized in a historical narrative that enriches the analysis, the results, and the inferences drawn.
The theory of lateral pressures, then it its infancy, was readily mapped onto a set variables and processes that represented growth, expansion, intersections of interests, conflict and violence. Below shows the logic of empirical investigation at that time. All variables, dependent and independent, other than the ultimate dependent variable, violence, were derived from existing statistical record, adjusted appropriately for comparison across countries and over time. The final dependent variable was constructed based on a 15-point international interaction scale developed for that purpose. This was long before measuring intensities of hostility in world politics became common practice in the field. In retrospect, it is clear that this study preceded the development of formally framed state profiles, as it did the quantitative articulation of the propensities for expansion, rather than the actual behavior.
Shortly thereafter, The Political Economy of War and Peace (Ashley, 19802) extends the lateral pressure logic, as well as the measures and metrics, into a system of simultaneous equations representing conflict dynamics among competing powers in the post-World War II era. Ashley focused on the interactions generated by differentials in growth of population, resource access, and levels of technology focusing on the United States, the Soviet Union, and China. This book this demonstrates the close interconnections among national growth, bilateral rivalry, and multilateral balance of power. It is also the first quantitative analysis of these three Powers in world politics.
The study shows how the dynamics of insecurity and the antagonizing processes contribute to the globalization of military competition, which in turn, creates serious impediments to the collective management of many dimensions of growth itself. Careful model development, empirical grounding and parameter estimation as well as simulation of sensitivity analysis revealed the overall security problematic surrounding major power interactions. Despite changes in world politics since 1914, and the processes modeled in Nations in Conflict, some fundamental features of lateral pressure retained powerful resonance during the post-World War II period.
In retrospect, despite the end of communism and the dissolution of the Soviet Union, the analysis as well as the results shed important light on the emergent challenges to global and national security in the 21st century. The unquestionable dominance of the United States in world politics does little to dampen perceptions of threat due to China‘s growth given its rapid expansion in the global economy, nor perceptions of Russian threat given its period encroachment on the sovereignty of select neighbors.