We’ve long been told by the foreign policy establishment (aka the Blob) that war between great powers is mathematically encoded into the structure of international politics. For generations, the Blob’s dark, deterministic and devoutly bipartisan fatalism has taken root in the corridors of power. Analysts and statesmen have viewed the shifting tectonic plates of global power as an inescapable conveyor belt leading directly toward interstate conflict.

This deep geopolitical anxiety has found its modern vocabulary in the “Thucydides Trap.” The concept, popularized by political scientist Graham Allison, warns that when a rising power threatens to displace an established ruling power, war becomes the historically expected outcome. Scholars constantly point back to the ancient Greek historian Thucydides’ famous assessment that “it was the rise of Athens, and the fear that this inspired in Sparta, that made war inevitable.”

Today’s strategists map this ancient framework onto the contemporary turbulent relationships between established great powers and their ascendant rivals, treating geopolitical friction not as a series of manageable human errors, but as an unalterable, structural law of nature.

However, I reject such systemic and ubiquitous fatalism. Fifteen years ago, my sweeping exploration of the realism (The Realist Tradition in International Relations: The Foundations of Western Order, PSI, 2011) convinced me that we are not helpless prisoners of historical cycles, nor are states passive victims of structural fate. The Thucydides Trap is a psychological prison of our own making, and we possess the agency to break its locks.

To do this, I proposed a framework I call Constructive Realism. This approach reconciles the harsh truths of power politics with the profound reality of human agency. It acknowledges that structural constraints exist, but it refuses to let those constraints dictate our destiny. Leaders can consciously shape their strategic choices, reject the false binary of zero-sum competition, and avoid the devastating cycles of hegemonic war.

The Problem with Structural Fatalism

Traditional realism assumes that the international system is anarchic, states are rational actors seeking survival, and the distribution of material power dictates state behavior. Under this view, when a rising state gains economic and military might, the established power panics. The rising state feels a growing entitlement to prestige and global influence, while the ruling state interprets every single move as an existential threat. A classic security dilemma follows: actions taken by one side to ensure its own security are viewed by the other as active preparations for war.

However, traditional realism commits a critical error by removing human choice and agency from the equation. It reduces complex nations to uniform billiard balls knocking into one another on a table. It implies that regardless of who is in power—whether statesmen are wise, reckless, diplomatic, or deeply paranoid—the structural outcome remains predetermined.

This structural fatalism is inherently dangerous. When leaders fully believe that war is inevitable, their behavior shifts fundamentally. They stop looking for diplomatic off-ramps. They begin to treat compromise as a weakness and dangerous escalation as prudence. The shared belief that a conflict is inevitable becomes a self-fulfilling prophecy, and fear, rather than rational calculation, takes the steering wheel of global statecraft.

The Alternative: Constructive Realism

Constructive realism offers a vital corrective to this flaw. It bridges the gap between traditional realism and constructivism. While realism focuses heavily on material power and structural anarchy, constructivism reminds us that international relations are socially constructed. The identities, core interests, and threat perceptions of states are not fixed in stone; they are continuously forged through human interaction, political rhetoric, and strategic choice.

Constructive realism asserts that geopolitical reality is malleable. The international structure sets the stage, but human leaders write the script.

First, consider agency over structure. While structural conditions impose clear constraints, the actual paths nations take are determined by deliberate strategic choices. The transition of power does not mechanically trigger global war. History shows us that peaceful power transitions are entirely possible. Structure did not doom earlier generations to fight, just as structure does not doom us today.

Second, we must actively manage fear. Traditional realism correctly identifies fear as a primary driver of conflict, but it treats fear as an unmanageable constant. Constructive realism focuses on diagnosing and actively managing the psychological drivers of geopolitical insecurity. It requires dominant powers to understand a rising power’s legitimate desire for respect and integration into the global order. Simultaneously, it requires rising powers to recognize and respect the ruling power’s deeply-rooted security concerns.

By addressing these perceptions directly through diplomatic engagement, states can open doors for mutual accommodation. We can maintain a stable balance of power through careful, empathetic diplomacy, rather than relying solely on brute deterrence and military mobilization. (This was, to my great relief, on display during President Trump’s cordial summit with President Xi in Beijing, where the Thucydides Trap was openly discussed by the very world leaders most able to escape it.)

Transcending the Trap

To transcend the Thucydides Trap, emerging and dominant powers must actively construct entirely new narratives of cooperation. For generations, international relations discourse has been overly saturated with zero-sum competition, where the Blob saw every economic policy, technological breakthrough, and diplomatic summit through the distorted lens of an impending cold war. If one side won a trade agreement or a technological race, the other side assumed it had lost vital ground.

Instead, constructive realism demands that we build positive-sum frameworks. There are vast, critical arenas where the ultimate interests of great powers converge, including global economic stability, climate volatility, pandemic prevention, and collaborative management of disruptive technologies such as artificial intelligence. When states anchor their relationships in their shared vulnerabilities, they can agilely rewrite the rules of their engagement.

The Path Forward

The Thucydides Trap is not a law of physics. The rise of Athens and the fear of Sparta did not make war inevitable; the specific choices made by Athenian and Spartan leaders made war seem inevitable. They allowed fear to blind them to alternative paths, choosing pride over prudence, and military mobilization over diplomatic negotiation. Add in a little bit Hellenistic hubris to this volatile mix, and the ruinous path to tragedy came to be perceived as all but inevitable. It wasn’t.

We stand today at a similar historical crossroads; the structural pressures of a shifting global balance of power are real, and they are immense. But they do not hold the pen that writes our future. We do.

By embracing constructive realism, we can acknowledge the realities of power without succumbing to its worst, most destructive impulses. We can recognize that our rivalries are real, but also accept that our survival is shared.

We have the agency to shape our strategic choices. We can manage our fears, rewrite our competitive narratives, and deliberately choose a path of peaceful coexistence. The trap is open, it always has been; it’s up to us to see this, and carefully avoid its grasp.