The Great Powers and the International System: Systemic Theory in Empirical Perspective: Summary & Key Insights

Every theory of international relations begins with a vision of how power operates among states. Realism, for instance, teaches that ambition and survival drive national behavior, and that structure—a system defined by anarchy—imposes discipline on the chaos of state interaction. Liberalism counterbalances that by emphasizing cooperation, institutions, and the transformative potential of interdependence. Constructivism reminds us that power is not merely material but also social, embedded in norms and identities.

These perspectives have inspired extraordinary insights, yet each falls short of explaining the full complexity of systemic interaction. Realism captures the constraints of an anarchic world but often treats the system as a static backdrop. Liberalism illuminates pathways of cooperation but sometimes neglects the deeper structural realities that limit collaboration. Constructivism foregrounds meaning and norm creation but can struggle to quantify systemic effects. What links all these theories is a tendency to focus on one side of the equation—either the state or the system—without rigorously integrating both.

My dissatisfaction with these limitations grew as I examined empirical data from the great power era. The system undeniably exerts influence, but its influence is not constant; it shifts as the distribution of power changes. Similarly, states respond to systemic pressures, but in doing so they rewrite those very pressures for others. International relations, therefore, cannot be fully understood unless we conceptualize mutual causation—the idea that states and systems coevolve.

My goal in laying the theoretical foundation was to show that structural realism’s emphasis on constraint and liberalism’s focus on agency represent two sides of a single dynamic. The challenge was not to choose between them but to design a theory capable of capturing how they interact empirically. This required formalizing the feedback process, treating systemic forces and state actions as interdependent variables, and grounding their relationship in observable historical patterns.

As I reflected on decades of theoretical debate, I came to see the discipline’s fragmentation as both a problem and an opportunity. The missing link was methodological: without an empirical way to test systemic feedback, we were left arguing in circles. To move beyond this impasse, the book needed to marry theory with data in a framework that could illuminate the causal architecture of the international system itself. That was the foundation upon which everything that follows would be built.

Defining the international system as a dynamic structure required breaking from traditional conceptions of structure as immutable. In my view, the system is neither a mechanical hierarchy nor a vague social construct; it is an ongoing process that links the distribution of power and the choices of powerful states through feedback.

Think of the system as a set of relationships that both constrain and are shaped by behavior. When great powers form alliances, pursue wars, or establish institutions, they alter the balance of power. That balance, in turn, redefines what actions seem rational or feasible. The system’s structure therefore evolves not because material resources fluctuate, but because states reinterpret what those resources mean in context.

This conceptualization rests on mutual causation. The systemic configuration—the arrangement of power among actors—sets boundaries for what states can effectively do. Yet the decisions they make collectively modify those boundaries. For instance, efforts to deter conflict may stabilize the system temporarily but can also breed new dependencies that later produce instability. The relationship is not linear; it is dialectical and cyclical.

In constructing this framework, I sought to provide clarity about levels of analysis. The state level is where decisions are made—policy choices, military strategies, diplomatic negotiations. The systemic level is where those decisions aggregate into patterns—alliances, orders, rules, or wars. Neither level is primary; each both precedes and follows the other. This mutual influence is the key to understanding how international systems change.

To illustrate this point, consider the aftermath of the Napoleonic Wars. The settlement at Vienna did not merely reset borders; it established norms of consultation among Europe’s great powers, institutionalizing the Concert of Europe. That system constrained unilateral aggression for decades, but it was sustained only through continuous state-level reinforcement. The stability of the system was thus both a product of and a condition for state behavior.

Recognizing this reciprocal logic helps us see why international history unfolds as it does. The system molds behavior, but the mold itself is soft—reshaped by every significant great power decision. The conceptual framework I propose formalizes this very idea and prepares the ground for a systemic theory that captures the dynamic interplay between agency and structure.