The “Thucydides Trap,” according to Graham Allison’s recent Destined for War (2017), describes the moment “when a rising power threatens to displace a ruling power” (p. xvi). Following so-called realist readings before him, Allison locates the origins of international conflict in a two-step structural process first described by Thucydides: the rise of Athens and the fear inspired in Sparta which made war inevitable. This logic of conflict supposedly meant that Athens and Sparta were “destined for war”—and illuminates a frequent destiny for states in similar circumstances.

S.N. Jaffe’s Thucydides on the Outbreak of War provides an important corrective to this common, indeed practically hegemonic, reception of Thucydides. The reading of Thucydides as an archetypal realist, Jaffe argues, misses how the causes of the war do not lie solely in an external structural necessity but also in complex psychological and cultural responses unique to Sparta and Athens. Although Thucydides does maintain a general view of the necessity behind the conflict, on Jaffe’s reading this necessity unfolds from the particular view of the good held by each party to war. Athens and Sparta are not destined for war; they choose war for complicated reasons and compulsions distinctive to each of them.

Jaffe builds this argument through a close reading of just the first (of eight) books of Thucydides’ History. The “commentarial form” of his analysis traces the text as Thucydides presents it, only occasionally reaching beyond these chapters as it moves from beginning to end of the book. Following the approaches of Leo Strauss and Clifford Orwin, among others, Jaffe excludes nearly all considerations of the social and political context of the Histories, instead offering an “internal reading” that focuses on the “underlying authorial intention” and thematic purposes evident in the text itself (p. 8).

Although the book follows the order of Thucydides’ text, Jaffe organizes his broader argument into five general claims. First, he suggests that Thucydides is interested in human nature and not just the nature of international systems, as realists have long maintained. Key episodes in the History reveal concentrated attention on characteristic behaviors to which states are prone. The initial quarrel between the Athenians and the Spartans provoked by the desperate situation of Potidaea does not just illuminate their particular qualities, but rather how and the degree to which regime type shape responses. Thucydides directs his readers’ attention to differences in character even as he promises to elucidate a more general pattern of interstate conflict.

Thucydides’ interest in human nature, moreover, does not lead him to efface the particularity of different state actions. Jaffe’s second general claim complicates his first by insisting that Thucydides’ account of human nature is “largely psychological” (p. 9). Thucydides illuminates how particular psychological “dispositions, attitudes, or beliefs” meet particular moments (p. 9). In other words, the meaning of Thucydides’ generalizations depends entirely on the circumstances of its unfolding. Thucydides’ treatment of such moments also allows his readers to evaluate from a distance: while a character in the History may advance an argument for a strategic purpose, Thucydides’ framing of these as examples of broader phenomena within human nature opens possible questions. When the Spartans, Corinthians, and Athenian envoys discuss the Potidaea situation, Jaffe shows how Thucydides’ treatment places the specific arguments of the speeches in a broader context of fear, honor, and profit. Each regime prioritizes these forces in a different way according to their dispositions; yet at a higher level of generality, these passions explain why actors go to war despite strong arguments to the contrary.

Thucydides’ political psychology, Jaffe maintains with his third general claim, appears as a catalogue of success and failure. By juxtaposing actors’ speeches and descriptions of events, on the one hand, with his own accounts of “what really happened,” Thucydides presents an implicit view of how and why actors went wrong. The Corinthian envoys, for example, describe how the Athenians align their speech and deeds whereas the Spartans distrust their own judgments. Yet placed in the broader context of characteristic overestimation of their capacities by the Athenians and underestimation by the Spartans, Thucydides, on Jaffe’s reading, furnishes “the formal requirements of successful political action” (p. 70), illuminating how misperception leads to error and thus the degree to which prudence depends on a clear-eyed assessment of the political lay of the land.

Within the structure of the History itself, however, the “national characteristics” of Athens and Sparta prove decisive for the outbreak of the Peloponnesian War. This assertion forms Jaffe’s fourth general claim, which he qualifies by underscoring how each of their particular dispositions stems from a common human nature. Thucydides presents this “programatically” (p. 11) according to Jaffe, putting on display the political passions and how these manifest themselves in different regimes. In the Archaeology, for instance, the differences among the development of Athens and Sparta appear as products of disparate cultivations of a common nature: “Partly in response to their original geographic circumstances, particularly the quality of the soil, Athens and Sparta developed distinctive historical trajectories, which in turn contributed to the tropoi [sc. ways or essences] of the cities” (p. 156). Athens and Sparta become themselves through a complex interplay of material factors and political responses to these factors. Thucydides thus sees structure developing through serial responses similar to what Sartre called practico-inert reality.

The differences among Sparta and Athens inform Jaffe’s fifth general claim: that the internal logic of Book I adumbrates how the outbreak of the war stemmed in part from Sparta and Athens’ particular perceptions of the triggering events themselves, perceptions that generate “a different but no less compelling necessity for war” (p. 12). The History thus reveals a “dynamic combination of character and strategic circumstance” (p. 192) that complicates structural explanations with second image ones. Necessity is “characterological” (p. 197), meaning necessity emerges when attitudes specific to actors and their psychology confront events. The “inevitability” to which Allison and his realist forebears refer is a perception among other perceptions, both shaped by the particular regime that identifies it, as well as remaining capable of miraculous transformation.

What Allison takes as objective inevitability—the destiny for war—Thucydides, on Jaffe’s reading, shows as partly a product of the subjective views of the actors themselves. Although he does not comment directly on it, Jaffe’s interpretation points to an important aspect of a much-discussed passage in the History: Book I, section 23, line 6. What Allison refers to as the “most frequently cited one liner” he glosses as “It was the rise of Athens and the fear that this constituted in Sparta that made war inevitable” (p. vii). But Thucydides’ text does not contain quite the causal structure that Allison (who relies on the Robert Strassler edition of Richard Crawley’s translation) imputes. Thucydides’ Greek separates the Athenians’ “growing power” from “inspiring fear.” It’s both their power and Sparta’s reaction to them that explain the outbreak of the war. Jaffe’s interpretation highlights a disjuncture already within Thucydides’ text between the material transformation of one party and the perception of another. How did the Athenians come to inspire such fear? And what was it about the Spartans that positioned them to become this fear’s object? Jaffe’s careful study offers the beginning of a response; yet a fuller response would require attention to the remainder of the History, a task which Jaffe does not take up. Attention to the rest of Thucydides’ classic thus awaits further inquiry.