Our focus is on the dynamics of transformation and change worldwide, articulated in the theory of lateral pressure—developed in collaboration with the late Robert C. North—discussed further along. Traditionally, international relations theory has focused on power and the purpose of humans in the geospatial domain, with the state system as the dominant organizational principle. Growing scientific evidence of the human impact on the natural environment calls into question the human-centric view of our world and its forms of international relations. Then, too, the construction of cyberspace, with the Internet at its core, enabled and forged new venues of interaction and the virtual domain assumed a salient position in human interactions—and in relations among states and other entities worldwide.

New Fundamentals

By the end of the 20th century, changes in the world around us—the "empirical realities" as well as methods, policies, and practices—led to a reframing of fundamental principles, assumptions, and expectations, and therefore of overall international relations theory. Our theory of international relations is explicitly anchored in a now obvious and powerful "reality," namely that all humans are embedded in three distinct interconnected systems—"spaces" or domains—that jointly shape an overarching framework:

  • The social system with all forms of human interactions, order and disorder
  • The natural environment with life supporting properties and various forms of life
  • The constructed cyberspace with the Internet at its core and rapid changes in its structures, processes, and configurations.

The overarching frame is "set," so to speak, by the parameters of these systems. Individuals, groups, or other aggregations do not have the choice of "opting out" of the social system or of the natural environment and, at this time, few select to "opt out" of the cyber domain. Each system harbors forms of complexity and threats to sustainability at various levels of intensity. Figure 1 below, albeit at a high level of abstraction and in a highly stylized fashion, illustrates the defining trajectories of human intersections and the adjacent spaces between them.

Theory Figure 1. New Fundamentals: High-level View
Figure 1. New fundamentals: high-level view.

Figure 1 is static in form. It is intended to represent "spaces" of human interaction and "spillover effects." But framing the fundamentals is the product of long term research, empirical analysis, and theory testing and development—bits and pieces, one step at a time. By way of illustrating Figure 1 in international relations theory, we frame the trajectories and adjacent spaces in the context of threats to security and sustainability (from Low to High in each case) in Figure 2.

Theory Figure 2. Illustrating Trajectories & Adjacent "Spaces"
Figure 2. Illustrating trajectories & adjacent "spaces."

In the context of Figure 2, it is fair to say that the major challenge – for theory, policy, and practice – is to understand the processes and, to the extent possible, the interactions and intersections among the trajectories. See What Next?

Clearly Figures 1 and 2 are "static" in form. They are not intended to represent transformation and change in international relations. But framing the fundamentals is the product of long term research, empirical analysis, and theory testing and development—bits and pieces, one step at a time.

Simple as that might seem, this basic "reality" generates complexities and uncertainties in almost all aspects of international relations. More important, however, it generates new challenges as we consider "system boundaries" for any issue of industry and at any level of analysis. Porosity is the rule, not the exception; and interconnection is the defining feature for trajectories of the overarching global system.

Theory in Brief

What follows is a brief introduction to the development of lateral pressure theory. The focus is elements of theory. The research that supports the theory – conceptual and empirical – is reviewed in another segement of this website. By separating matters of theory from those of research, we seek to be as transparent as possible and, to the extent possible, to retrace and highlight the investigations—both general and specific.

Lateral Pressure—Dynamics of Change

Lateral Pressure refers to any tendency (or propensity) of individuals, societies, and states to expand activities and exert influence and control beyond their established boundaries, whether for economic, political, military, scientific, religious, or other purposes. Lateral Pressure theory seeks to explain the relationships between characteristic features of states and patterns of international behavior. The theory addresses the sources and consequences of such a tendency.

Logic of Lateral Pressure—Causal Logic

The causal logic runs from the internal drivers – population, resources, technology – the master variables whose interactions define the profiles of states and, through intervening processes, shape their external behavior. State profiles are defined by the relative salience of the individual master variables (measured empirically).

Central to lateral pressure theory is the defining proposition of differential rates of change. The complexity lies in the fact that the proposition covers:

  1. differentials among the master variables (population, resources, and technology) within countries,
  2. differentials among the master variables between countries, and
  3. differentials among master variables differentials across countries.

As states expand their activities outside territorial boundaries, they encounter other states similarly engaged. Expansion may result in intersections among spheres of influence and set in motion complex interactions that can lead to escalation and conflict – or to cooperation and collaboration – depending on intents and capabilities.

Theory Figure T4 Simplified causal logic of lateral pressure theory.
Figure 4. Simplified causal logic of lateral pressure theory.
Source: Choucri and Agarwal (2017).

Theory — "Real" World

Drawing on insights and evidence from the social sciences (as well as natural sciences and, more recently, engineering), lateral pressure theory can be understood in terms of its basic assumptions, its components, and their interconnections. Our quantitative analysis of the "real" world – defining actors, entities, systems of interactions, and forms of behavior – is summarized by a set of specific features that individually and jointly signal departures from conventional theory in international relations. Ten propositions highlight the core of lateral pressure theory.

Phases of Theory

The development of lateral pressure evolved over six phases of inquiry, each with its own theoretical and methodological features and challenges. The first three concentrated on the traditional geospatial realm, the "real" world. The fourth and fifth phases focused on the effects of human activity on the natural environment and implications for sustainability—two then-novel features of international relations and world politics. The most recent phase focused on the construction of cyberspace—with its new data challenges, measures of master variables,  analysis of state profiles, and propensity for expansion.


This new domain of interaction is a source of vulnerability, a potential threat to national security, and a disturber of the familiar international order. It has already created major changes to structures and processes of international relations. To date, we have addressed select critical imperatives—namely, challenges to the state, new security dilemmas, states defined in terms of cyber vs. real profiles, and modes of lateral pressure in "real" vs. cyber domains. These all point to a disconnect between the state-centric features of traditional international relations – with its defining principles – and the character and ubiquity of cyberspace.

What Next?

It also should not come as a surprise that each phase of theoretical development – and empirical inquiry – explored different modes of analysis, as we become more and more aware of the complexity inherent in 21st century IR theory and the underlying realities that this theory seeks to capture.

Next steps include attention to:

  • Dynamics of lateral pressure within and across each of the three domains—society, environment, and cyberspace; 
  • Ramifications for the international system in terms of conflict and cooperation, and everything in between;
  • Impacts of lateral pressure on sovereignty and society, and attendant consequences;
  • Effects of, and on, public and private sectors and their interactions; and, to the extent possible,
  • Measures and assessments of sustainability—at different levels of analysis, as well as within and across the increasingly human, environmental, and cyber systems
  • Innovations and applications of Artificial Intelligence (AI)


Choucri, Nazli, and Gaurav Agarwal. 2017. "The Theory of Lateral Pressure: Highlights of Quantification and Empirical Analysis" In The Oxford Encyclopedia of Empirical International Relations Theory, edited by William R. Thompson. New York: Oxford University Press.