Lateral Pressure refers to any tendency (or propensity) of individuals and societies to expand their activities and exert influence and control beyond their established boundaries, whether for economic, political, military, scientific, religious, or other purposes (Choucri and North, 19721; 19752; Ashley, 19803; Choucri and North, 19894; North, 19905; Lofdahl, 20026). Framed by Robert C. North and Nazli Choucri, the theory addresses the sources and consequences of such a tendency.


Lateral Pressure theory seeks to explain the relationships between state characteristics and patterns of international behavior. The theory addresses the sources and consequences of transformation and change in international relations and provides a basis for analyzing potential feedback dynamics. The causal logic runs from the internal drivers, the master variables that shape their the profiles of states -- through the intervening effects of socially aggregated and articulated demands and institutional capabilities -- toward modes of external behavior designed to meet demands given the capabilities at hand (Choucri and North, 19894). To the extent that states expand their activities outside territorial boundaries – driven by a wide range of capabilities and motivations – they are likely to encounter other states similarly engaged. The intersection among spheres of influence is the first step in complex dynamics leading hostilities, escalation, and eventually to conflict and violence. These processes are contingent on the actors’ intents, capabilities, and activities.

Lateral pressure is a relatively neutral concept similar to what Sorokin (1957: 565)7 called economic expansion and Simon Kuznets (1966: 334-348)8 referred to more broadly as outward expansion. The strength of a country's lateral pressure is generally taken to correlate positively with its power as conventionally understood. The theory of lateral draws on the level of analysis or Image perspective in international relations (Boulding, 19569; Waltz, 197910) largely as an initial framing and then extends this traditional perspective in specific ways.

When Choucri and North (19721; 19752) formulated the theory of lateral pressure in qualitative as well as quantitative terms, they signaled that, in general, the strength of a country's lateral pressure correlates positively with its capabilities and power, (a concept that is almost universally used but defined with difficulty). Lateral pressure theory provides a more detailed and nuanced view of the sources of power, the types of leverages used, and the behaviors that can be inferred. It suggests how certain types of international behaviors or activities appear to be more prevalent in some countries than others. Among the notable reviews of lateral pressure theory are Levy (2005)11; and Schweller and Pollins, (1999)12.

What follows is this: First we highlight the basic features of lateral pressure theory, its core components, and their interconnections. Some aspects are more readily quantifiable than others. Some are more consistent with conventional theory in international relations. Others are based on assumptions that depart from tradition by adopting a multidisciplinary perspective, thus drawing on insights and evidence from other areas of knowledge. Second, we summarize the phases of empirical investigations and the evolution of theory over time. Third, we return to basics and focus on the refinements of metrics and quantification of the core concepts. All of this pertains to the world, as we have known it prior to the construction of the Internet, the core of cyberspace. Fourth, we then review briefly the work to date on lateral pressure in the cyber domain.  The End-Note highlights some emerging imperatives.

We cannot assume the portability of theory and of methods from the traditional physical domain to the cyber arena. Nor can we assume a one-to-one correspondence of metrics and measures. Fourth, we turn to empirical evidence of propensity for state expansion in the cyber domain compared to expansion tendencies in the kinetic, or traditional international arena. Finally, we ask: where do we go from here? What are the major theoretical and empirical challenges? In today’s world, the state remains the dominant, but not the only significant entity in world politics.  How relevant is the theory of lateral pressure for other actors in world politics, both private and public?  What are generic features of international relations in an increasingly complex world where the cyber and the “real” arenas are increasingly interconnected, and where the natural environment is “endogenized” in theoretical, empirical, and policy analysis?

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  1. Choucri, N., & North, R. C. (1972). In Search of Peace Systems: Scandinavia and the Netherlands, 1870-1970. In Russett, B. M., & American Political Science Association. (1972). Peace, war, and numbers. Beverly Hills Calif.: Sage Publications.
  2. Choucri, N., & North, R. C. (1975). Nations in conflict: National growth and international violence. San Francisco: W.H. Freeman.
  3. Ashley, R. K. (1980). The political economy of war and peace: The Sino-Soviet-American triangle and the modern security problematique. London: F. Pinter.
  4. Choucri, N., & North, R. C. (1989).  Lateral Pressure in International Relations: Concept and Theory. In Midlarsky, M. I. (1989). Handbook of war studies: [1]. Boston [u.a.: Unwin Hyman.
  5. North, R. C. (1990). War, peace, survival: Global politics and conceptual synthesis. Boulder: Westview Press.
  6. Lofdahl, C. L. (2002). Environmental impacts of globalization and trade: A systems study. Cambridge, Mass: MIT Press.
  7. Sorokin, P. A. (1957). Social and cultural dynamics: A study of change in major systems of art, truth, ethics, law, and social relationships.
  8. Kuznets, S. (1966). Modern economic growth: rate, structure, and spread. New Haven: Yale University Press.
  9. Boulding, K. E. (1956). The image; knowledge in life and society. Ann Arbor: University of Michigan Press.
  10. Waltz, K. N. (1979). Theory of international politics. Reading, Mass: Addison-Wesley Pub. Co.
  11. Levy, D. L., & Newell, P. (2005). The business of global environmental governance. Cambridge, Mass: MIT Press.
  12. Pollins, B., & Schweller, R. (1999). Linking the Levels: The Long Wave and Shifts in U.S. Foreign Policy, 1790- 1993. American Journal of Political Science, 43(2), 431-464.