IV. Dynamics of International Conflict

Major studies of the entire lateral pressure proceed from internal dynamics to escalation, and eventually war, followed with a detailed analysis of the "master variables"—with population, resources (petroleum/energy), and technology as three difference entry points.

Lateral Pressure Theory

The theory traces empirically the sources of conflict and violence to the dynamics of growth and development rooted in the internal conditions of states. It is rooted in the assumption that the master variables – population, sources, technology, and their interaction – constitute the fundamental building blocks of state power with capabilities with attendant impacts on the natural environment.

Different combinations of the master variables shape different state profiles, each with different propensities for external behavior. Through a set of intervening variables and processes, they pursue different modes of international activities that, under certain conditions, lead to competition, alliances, counter alliances, and, eventually, to conflict and warfare.

Also included here is Forecasting in International Relations, the first such collaborative effort among scholars of world politics.


The first phase of lateral pressure theory, application to international conflict, focused on the evolution and consolidation of contentions and, eventually, the breakout of war among the six great powers from 1870 to 1914. Drawing on historical inquiry first, we developed a conceptual model of these interactions. This model framed a context for quantitative analysis—estimating the parameters of a system of simultaneous equations.

Elements of Conceptual Model for Dynamics of International Violence
Elements of conceptual model for dynamics of international violence.
Source: Choucri and North (1975, 22).

The figure below shows a schematic view of the conceptual model, and a transition to the econometric analysis. The "boxes" signal the dependent variables and the links are the independent variables.

Conceptual Model for Dynamics of International Violence
Conceptual model for dynamics of international violence.
Source: Choucri and North (1975, 22).

Each equation in the model represents a "piece" of a dynamic system of simultaneous equations, with the variables signaling the individual factors shaping the overall dynamics of conflict over time. The system of equations represents (a) growth and expansion, (b) intersection and collision of national interests, (c) military competition leading to increasing military expenditures, (d) alliances and counter-alliances, and (e) evidence of violent behavior—all constituting the escalating dynamics of a conflict spiral that almost inevitably results in war.

Below we show select results for illustrative purposes:

First are the historical, forecast (from empirical data), and simulation (replication from initial conditions and coefficients) for Great Britain, followed by those for Germany.

Total British Colonial Area 1871-1914. Total German Colonial Area 1871-1914.
Total British colonial area 1871-1914.
Source: Choucri and North (1975, 250).
Total German colonial area 1871-1914.
Source: Choucri and North (1975, 250).

Then, we show the results for military expenditures—again for Britain and Germany.

Total British Military Expenditures 1871-1914. Total German Colonial Area 1871-1914.
Total British military expenditure 1871-1914.
Source: Choucri and North (1975, 265).
Total German military expenditure 1871-1914.
Source: Choucri and North (1975, 265).

Note the difference in the effectiveness of the model for these cases. All other results for the six countries, data sources, and methods can be found in Nations in Conflict: National Growth and International Conflict.


Choucri, Nazli, and Robert C. North. 1975. Nations in Conflict: National Growth and International Violence. San Francisco: W.H. Freeman.

In collaboration with Robert C. North and Suzumu Yamakage, The Challenges of Japan follows Nations in Conflict in the form of a large-scale longitudinal analysis focusing on Japan from the Meiji Restoration, through two World Wars, and into the 1970s.

The country's uneven development – shaped by its population resources, constraints, technology advances, and population dynamics – posed serious challenges to the international order, leading to conflict and war, followed by periods of peace, and then more war, over a period of one hundred years or so. We explored the sources and consequences of national growth and external expansion for international security, competition, and warfare—and the system breaks.

A combination of historical narrative and econometric analysis with a system of Simoleans equations traces the complex challenges before World War I and after, and before World War II and after.

Below, we show the model for the period of 1914-1941.

The Japan model leading to war, 1914 and 1941: Overview of the system.
The Japan model leading to war, 1914 and 1941: overview of the system.
Source: Choucri, North and Yamakage (1992, 105).

World War II initiated a major system break that required a re-specification and re-estimation of the entire system of simultaneous equations from 1945 to 1970. See The Challenges of Japan Before World War II & After, 1992, for the data sources, models, and results.


Choucri, Nazli, Robert C. North, and Susumu Yamakage. 2006. The Challenge of Japan Before World War II and After: A Study of National Growth and Expansion. London: Routledge.

Below we report on the role of drivers of international conflict – the "master variables" – with the understanding that we consider interactions among the three master variables: population, resources, and technology.

Recall the properties of the master variables.

Population Dynamics

In Population Dynamics and International Violence we focused on the role of population variables – within the configuration of the master variables – in a set of international conflicts. Part I covered the literature dealing directly and indirectly with the relations between population dynamics and international violence, given the evidence to this point in time. Part II focused entirely on empirical materials gathered from an examination of violence in the developing world in order to explore systematically if and how population changes have influenced the beginnings or the outcomes of violent conflicts. Part III reviewed the results, identified major themes, summarized conclusions, and ended with a discussion of policy and research issues relating demographic variables to political behavior and conflict patterns.

Motivated by Population Dynamics and International Violence, the edited book Multidisciplinary Perspectives on Population and Conflict represents multidisciplinary research work focused on exploring further the relationships between specific population variables, on the one hand, and the manifestations of conflict, on the other, and puts forth some initial observations of the linkage factors that connect demographic conditions to propensities for hostility, escalation, and overt violence. The Preface, written by the Executive Director of the United Nations Fund for Population Activities signals the multidisciplinary nature of this effort.

The research provided an important integrating function in terms of theory and policy. Among the issues examined are the images policy makers have of population, the implications for the military, the role of historical memory, and influences on public policy. Insights from different fields – economics, sociology, psychology, and political science – helped to situate the role of population dynamics, and different population variables, in shaping the interactive trajectory leading to violence known as the conflict spiral.

 Energy Resources — Explorations, Modeling, Simulation

The first energy project, on International Politics of Energy Interdependence, focused on the worldwide interdependence generated by increased petroleum trade and higher prices, and the constraints on international behavior of virtually all states—created by the events surrounding the historic oil price hikes of 1973. The conflicts over petroleum prices, imports, and exports, and the distribution of market shares are symptomatic of more basic political differences. Part I is an introduction to petroleum politics and the world oil market. Part II examines the new tensions and strategic vulnerabilities that shaped the global order for the remainder of the 20th century. Part III presents a timely assessment of, and some speculates about, the potential effects of alternative energy sources.

Continued investigations into energy politics led to the development of International Petroleum Exchange Model (IPE), a system dynamics model to explore a set of propositions about future price, politics, and market configurations. Central to the analyses is the role of strategic vulnerability as a distinct variable that influences and is influenced by interactions among producers and consumers in a changing market.

This research initiative is distinctive for its adoption early on of system dynamics as the simulation method, rather than econometrics or other simulation approaches. Results are presented in a book titled International Energy Futures: Petroleum Prices, Power, and Payments (1981).

The book begins with an analysis of the politics of the international petroleum trade. Part II is the intellectual core of the book and focuses on the analytical structure of the IPE model and on the simulation results of interactions among key actors.

Analytical representation of IPE model.
Analytical representation of IPE model.
Source: Choucri (1981, 25).

A simplified view of the IPE model is shown in the figure below. Note the location of positive (reinforcing) loops versus the negative (balancing) loops throughout. These reflect the structure of the model. As shown, they generate the reference case.

Simplified model overview of major causal loops.
Simplified model overview of major causal loops.
Source: Choucri (1981, 30).

Part III appraises the model's results and their implications. And Part IV puts forth some tentative assessments of the model's predictive capacities and highlights alternative prospects for various energy policies given different price situations.

Research for Energy and Development in Latin America ( Chocuri, 1982) adopts an empirical as well as policy perspective. It goes without saying that even at the time we had serious concerns about the reliability and consistency of the data. First, is attention to the basic parameters of energy in the region with an emphasis on energy in transportation. Second, is a focus of economic factors, with a focus on the demographic drivers of economic activity and implications for transportation and development. Third, is a policy perspective focusing on the role of government, state petroleum enterprises, and pressure for social adjustment to new and stressful conditions. A final section addresses implications for transportation and puts forth the alternative criteria for policy choices consistent with different development objectives.

Foundations for Technology Imperatives

Early on we organized at MIT the first workshop of an international group of scholars to sketch out the boundaries and content of forecasting methods as applied to international relations. The researchers focused on: (i) foundational challenges, (ii) requirements of theory, (iii) methodological applications in international relations, (iv) the time perspective in forecasting, and (v) policy analysis in international contexts.

While the challenges are far greater than the tools to address them, the chapters of the book titles Forecasting in International Relations: Theory, Methods, Problems, Prospects, co-edited with Thomas W. Robinson, showed a wide range of intellectual capabilities focusing on forecasting around the date of publication.


Choucri, Nazli, Brian Pollins, and David Scott Ross. 1981. International Energy Futures: Petroleum Prices, Power, and Payments. Cambridge, MA: MIT Press.

Choucri, Nazli. 1982. Energy and Development in Latin America: Perspectives for Public Policy. Lexington, Mass: Lexington Books.