1. Introduction

In 2012, prominent American international relations scholar Graham Allison proposed the concept of the "Thucydides Trap" in an article he published in the Financial Times, likening Thucydides' account in The History of the Peloponnesian War of the causes of the Athens–Sparta war to U.S.-China relations [1]. He later expanded his view into a book in 2017, startlingly titled Destined for War [2]. Allison's career spans both politics and academia; he is one of the most important think-tank scholars in contemporary American international relations, and his striking assertions about U.S.-China relations quickly attracted widespread global attention.

It is worth noting that although Allison's concept is beloved by American politicians, it has been widely criticized by historians and international relations scholars worldwide since it was proposed. Historians' criticisms of Allison focus mainly on his insufficiently clear grasp of the factual details of the Peloponnesian War, which led him to build his theory on a misreading of the case, and on his erroneous interpretation of Thucydides' textual meaning [3]. International relations scholars, meanwhile, have questioned the applicability of his theory and the correctness of its theoretical foundations [4]. Thirteen years have passed since Allison's discussion of the Thucydides Trap appeared, and critiques by scholars at home and abroad across various dimensions are already fairly comprehensive, so the author does not intend to repeat them. What the author considers more worthy of attention is that Allison's understanding of Thucydides did not arise out of nowhere; in forming that understanding, he must have been influenced by prior international relations scholars' readings of Thucydides. This paper will attempt to trace the international relations field's earlier understandings and transformations regarding Thucydides and the relationship between Athens and Sparta in order to explore why Allison formed the conception of Thucydides and the Athens–Sparta relationship as expressed in Destined for War. In doing so, it offers a preliminary scholarly history of how Thucydides and his account of the Peloponnesian War were understood in international relations scholarship up to Allison's era, providing a basic foundation and clues for subsequent researchers.

2. Classical realism and early structural realism’s perception of Thucydides

Thucydides is one of the greatest writers of ancient Greece, the source of Western civilization; subsequent Western humanities and social science disciplines often trace their intellectual origins back to Thucydides. In the field of history, Thucydides is honored as “the first scientific historian” [5], and many of the main figures when the discipline of international relations formed in the early 20th century came from historical backgrounds. For example, the author of an important early work in international relations, World Politics at the End of the Nineteenth Century, Paul Reinsch, studied under Frederick Jackson Turner, a representative of the American frontier school, during his doctoral studies, while the author of another significant work, Survey of International Affairs, was the renowned historian Arnold Toynbee. Moreover, these scholars largely received a traditional Western classical education, so from its inception the field of international relations regarded Thucydides as an important source of ideas.

Since the 1920s, the realist school has risen within international relations scholarship. Scholars of this school regard Thucydides as “the first realist”; Joseph Nye even called Thucydides the Founding Father of realism [5]. The classical realist Hans Morgenthau’s emphasis on the importance of interest—“the identity of interest is the most reliable bond between states or individuals”—can be seen as deriving directly from Thucydides, and Kenneth Waltz, a representative of postwar structural realism, likewise considered Thucydides to be the earliest thinker concerned with the “use of force and the possibilities of controlling it” [5]. Although they all venerated Thucydides as an intellectual source and explicitly drew some theoretical resources from him, their works rarely engage with the Greek-world cases that Thucydides discussed. Hans Morgenthau’s most important work, Politics Among Nations, does not mention the relationship between Athens and Sparta at all, and while Kenneth Waltz invokes Persia and Athens in Man, the State, and War to illustrate the enduring logic of balance-of-power politics, and in Theory of International Politics points to the alliance choices of the Greek city-states toward Athens and Sparta to show that states typically side with the weaker coalition to preserve equilibrium [6], these examples occupy only a small fraction of both volumes and are deployed with notable restraint.

3. Power transition theory and Thucydides

The next major development of structural realism is the power transition theory. Allison starts from Thucydides’s classic statement about the cause of war: “It was the rise of Athens and the fear that this inspired in Sparta that made war inevitable,” and concludes that the reason war broke out between Athens and Sparta is, “When a rising power threatens the dominant position of a status-quo power, serious structural pressures are produced. In such circumstances, not only extraordinary, unforeseen events, but even the smallest, seemingly routine spark in diplomatic affairs can trigger large-scale conflict” [7].

This is also Allison’s so-called definition of the “Thucydides Trap.” From the way this definition is formulated, it is clear that Allison’s theoretical foundation comes precisely from the power transition theory in international relations. Scholars who adopt the power transition approach are clearly divided into two camps in their treatment of Thucydides. One camp includes Modelski, William Thompson, Immanuel Wallerstein, and others; like Morgenthau and Waltz, they acknowledge drawing intellectual resources from Thucydides but rarely or never focus on Athens and Sparta. They explicitly limit the applicability of their theories to the period after the early modern era. Take Modelski as an example: in his long-cycle theory the four states identified as world leadership powers are Portugal, the Netherlands, Britain, and the United States, with the chronological lower bound set at 1492 [8].

The other camp is represented by Robert Gilpin. Gilpin identifies Thucydides as the founder of hegemonic war theory and regards the Peloponnesian War as the first case of hegemonic conflict. Gilpin argues the basic idea of Thucydides’ hegemonic war theory is that fundamental changes in the international system are the basic determinants of such wars. The structure of the system, or the distribution of power among states, can be stable or unstable. A stable system is one in which changes can occur without threatening the dominant states’ vital interests and thus without leading to war among them. In his view, such a stable system is characterized by a clear hierarchy of power and an uncontested dominant or hegemonic power. An unstable system is one in which economic, technological, and other changes are eroding the international hierarchy and weakening the position of the hegemonic state. In such circumstances, adverse events and diplomatic crises may trigger hegemonic wars among the states within the system. The result of such a war is a new international structure [9]. Comparing Gilpin’s view with Allison’s, one can see that the meanings they express are almost identical. At the same time, Gilpin contends that the fifth century BCE was a period of dramatic economic, military, and social transformation in Greece: the rise of commerce and coined money, the formation of an interdependent international trade system, military technological innovations, the increased importance of naval power, and a rising commercial class driving Athens’ outward expansion—he effectively equates fifth-century BCE Greece with early modern Western Europe during the Age of Discovery. Contemporary distinguished classicists, using detailed data and rigorous scholarship, have demonstrated that Gilpin’s views on Greece’s economic and social conditions before the Peloponnesian War are erroneous; Gilpin ignored the findings of classical scholarship regarding Greece’s economic and social history.

So what about Allison? Similar statements can be found in Destined for War, where Allison asserts, the city-state of Athens experienced an astonishing revival economically, militarily, culturally, and in other respects. Its economic prosperity attracted merchants and seafarers from across Greece to serve in maritime trade. As trade expanded, Athens added a commercial fleet to supplement its formal navy, and by that time Athens’ navy was already twice the size of its nearest rival… In the fifth century BCE, Athens gradually transformed the defensive alliance system originally used against the Persians into a de facto maritime empire [7].

Their theories are roughly the same, and their understanding of Greek economic and social conditions is also largely similar—which means they commit the same factual errors—suggesting that Allison's theory is actually not merely an inheritance of Gilpin's but could even be seen as a kind of repetition of Gilpin's hegemonic war theory.

The difference is that Gilpin explicitly opposed using the hegemonic war theory to make predictions about future situations and acknowledged the theory's limitations. He wrote: "Although it provides profound insights into understanding and explaining great wars in history, the hegemonic war theory remains a limited and incomplete theory. It cannot easily handle cognition that affects behavior, nor can it predict who will initiate a hegemonic war. It also cannot predict when a hegemonic war will occur or its consequences. Like the theory of biological evolution, it helps people understand and explain what has already happened, but neither theory can make testable predictions that satisfy the strict standard of scientific falsifiability" [9].

Moreover, Gilpin likewise opposed simply applying the Athenian-Spartan pattern to modern great-power relations. For example, when discussing differences between the US–Soviet relationship and that of Athens and Sparta, he argued that the structure of the international system itself, the emergence of nuclear weapons, and the conservative behavior of the US and the USSR produced fundamental differences between the two cases [5]. These three important characteristics Gilpin identified are obviously still present in today’s US–China relationship, yet Allison ignores Gilpin’s view and insists on comparing US–China relations to the Athens–Sparta relationship.

Another notable point is that as early as 1989, at a conference on Thucydides and international relations, historians criticized Gilpin’s grasp of the facts of the Peloponnesian War and his interpretation of Thucydides’ text through factual examination and textual analysis of The History of the Peloponnesian War. For example, Richard Ned Lebow pointed out that the war did not break out when Athens' power reached its peak, but when Athens had already been greatly weakened by defeats in foreign wars and internal strife; meanwhile, Sparta was cautious in handling the conflict with Athens, even asking Corinth to resolve disputes through negotiation or arbitration when Athens clashed with that ally. And even when war did break out, Sparta underestimated Athens’ strength rather than viewing it as a rapidly expanding rival [5]. Marta Sordi emphasized the important role played by third-party allied powers like Corinth in the outbreak of the war—Athens and Sparta were driven to war by their respective allies [5]. Connar noted that the Greek world at the time was not a bipolar system as Gilpin understood it. There were many more criticisms besides these, but as the introduction to the conference volume said, "If the conference reached any consensus, it was a limited consensus" [5]. After that, the international relations field did not become more cautious in its use of Thucydides and the Peloponnesian War case.

4. Political identity factors inferred as the reason for Allison’s formation of his understanding

Allison proposed the concept of the “Thucydides Trap” more than twenty years after historians had voiced criticisms of Gilpin. Yet the criticisms contemporary historian level at Allison can almost all be matched to the critiques made of Gilpin over twenty years ago. In his critique of Allison, Qian Chengdan pointed out that Thucydides’ original text clearly states, “Although the Spartans were aware of the growth of Athenian power, they rarely, if ever, restrained it; for the most part they remained calm” [10]. Chen Cunfu noted that in the period before the war, Athens and Sparta still had other city-states as opponents, with relatively few intersecting interests between them. Therefore, Athens and Sparta were by no means a bipolar relationship [11]. These views are strikingly similar in essence to the criticisms made by scholars of Gilpin more than two decades ago.

This means that despite the many criticisms historians have made over the past twenty-plus years of the way international relations scholars interpret Thucydides and the Peloponnesian War, Allison did not learn from these critiques. He continues to cling to the traditional understanding formed in the early days of the international relations field. To analyze a historical case, one must first have a basic understanding of the facts involved—this is a scholar’s duty. That Allison, a long-established international relations scholar, ignored this is puzzling.

The first factor worth considering is Allison’s identity. When he wrote his series of articles and books on the “Thucydides Trap,” Allison was director of the Belfer Center for Science and International Affairs, a key think tank that provides direct policy input to the U.S. official decision-making apparatus. Its membership includes many senior figures in U.S. national security, including former secretaries and assistant secretaries of defense and a former CIA director—a typical “revolving door” institution. This gives the opinions its members voice a semi-official character. In U.S. political circles, since the Cold War there has been a tradition of likening contemporary great-power relations to the Athens-Sparta relationship. In a 1947 speech at Princeton University, U.S. Secretary of State George Marshall publicly declared, “I seriously doubt whether any man who has not at least in his mind reviewed the Peloponnesian War and the fall of Athens can think with full wisdom and with the deep conviction necessary to deal with some of the fundamental international questions of today” [12]. Allison’s provocative claim was very likely aimed to cater to the U.S. government’s hardline stance toward China and its strategic pivot to the Asia-Pacific, providing rationalization and discursive resources for official policy decisions. This helps explain why Allison offered no original insights, merely rehashing Gilpin’s decades-old refrain in the context of U.S.-China relations, and why he turned a blind eye to prior academic criticisms.

5. Allison’s perception and the “dehistoricization” of international relations

Although this explanation is a reasonable inference, it lacks solid evidence and does not strike at the heart of the matter. The example of Allison inventing the concept of the "Thucydides Trap" reflects a deeper problem: a rupture between the findings of historical scholarship and the field of international relations.

As Mr. He Yuanguo mentioned in his article, even a look through the most basic works on Greek economic history shows that Gilpin’s understanding of Greek economic society was mistaken. However, Gilpin disregarded the historical facts and forcibly squeezed Greek society into his theoretical framework. Such practice is common in contemporary international relations research. As noted above, when the field of international relations emerged, many of its important scholars were historians or at least had a background in history. As a discipline closely connected to history, how it has come to the point of trimming historical facts to fit theoretical arguments has become a significant problem.

The root cause lies in the rise of scientific behaviorism in the American social sciences after World War II. For the dominance of American social science over international relations, see Barry Buzan’s description, “Since the discipline was formally institutionalized after World War I, international relations have been dominated by the Anglophone world, and especially after 1945 it has been held by American IR scholars, who, with overwhelming advantages in personnel and resources, constructed the core of the discipline. Thus, this ostensibly international field became tightly bound to America’s main concerns and methodologies and was controlled by American journals and organizations.”

Scientific behaviorism borrows many research methods from the natural sciences, emphasizing analysis of relationships between variables and especially the use of quantitative analytical tools. It abstracts and simplifies historical events into individual variables and concepts, no longer examining historical cases within their concrete contexts, let alone verifying factual details. As this research paradigm has become dominant, historical scholarship has been increasingly marginalized in international relations research, to the point that model-building and quantitative analysis have saturated the field; even scholars who still use historical cases no longer pay attention to verifying factual details or drawing on new findings from the historical discipline to revise their theories but are content with outdated conventional wisdom or arbitrarily trim historical facts to fit their theories. Buzan pointed out, "The long-term hegemonic position of new positivism has weakened the connection between international relations and history. All strands of new positivism have dug into history for data, using an already existing past to provide empirical tests for abstract theories. The problem with this approach is that it fosters selection bias, reducing history to a role serving new positivist abstract theories. Thus, new positivists disregard history, using it merely to code their findings, extract data, or as a source for post hoc explanation, rather than as an effective tool for theory construction [13]." This is precisely what Allison did when he coined the concept of the "Thucydides Trap."

6. Conclusion

At this point, the question has an answer. The reason Allison developed the understanding of Thucydides and the Peloponnesian War displayed in Destined for War and ignored the wide criticism from historians is the result of two combined causes. First, as a senior official at a government-affiliated think tank, Allison catered to the needs of U.S. national strategy, providing a rationale for a China policy centered on containment and pressure. Second, Allison was influenced by the "dehistoricizing" trend in international relations since the rise of the American scientific behaviorism paradigm, particularly the precedent set by Robert Gilpin, and thus adopted a cavalier attitude when handling the historical case of the Peloponnesian War.

Although this article has traced a strand in the intellectual history of scholarship, its treatment remains undeniably rough. Two shortcomings are especially clear. First, it focuses on only a handful of canonical figures whose academic stature is well established, while neglecting many other scholars—less prominent yet still influential—who helped shape international-relations readings of Thucydides. Second, the timeline is too coarse: the gaps between key dates often exceed a decade, and within those span other scholars undoubtedly produced work that the article has yet to examine. Both of these points await further enrichment and refinement by future researchers. In addition, since Allison introduced the “Thucydides Trap” over a decade ago, a natural extension would be to trace the theory’s scholarly evolution after his initial statement, pushing the intellectual history as close to the present as possible.