Part I: The Dangers of Questions Dealing With Historical Causality and Inevitability

The question of when the Second Peloponnesian War became inevitable, like the related question of who or what was directly responsible for its outbreak, is a dangerously broad query. It seems to demand a specific answer, yet one can imagine multiple beautifully argued, well supported theses all standing like ducks in a row in stark contradiction to each other, with no systematic way for a reader to evaluate the relative truth of any of the claims. One could plausibly argue, for example, that Spartan fear of Athens made the conflict inevitable the moment the Persian War ended in 479 BC; or that Pericles’ commitment to imperialism in the Aegean was to blame for the struggle, symbolized by the movement of the treasury of the Delian League to Athens in 454 BC; or even that commercial rivalry between Corinth and Athens guaranteed a pan-Hellenic war in the late 430s. All of these theses and countless others like them can be supported to some degree or another by evidence from the surviving ancient sources. Because we cannot go back in time and “rerun” history from a plurality of starting points to see how different hypothetical timelines would have played out, no single explanation about causality and inevitability can be definitively challenged.

In trying to evaluate the truth of these sorts of theses, an historian is left with a battery of lame tropes, particularly reasoning by false analogy. For example, one might claim that the intensity of commercial rivalry with Corinth is an inadequate yardstick for deciding when war became inevitable because at previous points on the timeline, it did not lead to war; for example, Sparta did not immediately attack Athens when the conflict over Corcyra erupted, and at an even earlier point in history, Corinth supported Athens during its suppression of the Samian revolt (Thuc. 1.40). This sort of reasoning, however, is specious, comparable to saying “the question of when World War Two became inevitable does not center on the Nazi-Soviet relationship because at an earlier point in history, the nations were in treaty with each other.” The fact remains that commercial conflicts with Corinth were indeed a major factor when the Peloponnesian War finally did break out, whatever the situation was in the past. It is either the case that the question of inevitability intrinsically has an infinity of potentially correct answers that cannot be meaningfully evaluated against each other, or that the Second Peloponnesian War became inevitable once it was declared and the fighting had begun.

Of course, this seems like a singularly unsatisfactory answer akin to rhetorical sleight of hand. Our intuitions tell us that causality is usually more complex than literally proximate causes like the declaration of the war itself. Yet long term causes like “the growth of the power of Athens, and the alarm which this inspired in Sparta” (Thuc. 1.23) only seem meaningful given the benefit of historical hindsight. For example, it is easy for us now, knowing that the Peloponnesian War took place, to claim that in the extreme long term, as Thucydides said, Spartan fear and Athenian imperial progress were to blame for the conflict. Yet during the fifty year interval separating the Persian War from the Peloponnesian War, we neither find Athens aggressively pursuing an explicitly imperial policy at all times, nor Sparta equally willing to go to war at all times; indeed, even when Athens eventually allied with Corcyra, it was explicitly a defensive compact, and the assembly at which the Spartans at last voted to go to war was too close to call by acclamation (Thuc. 1.87). If World War 3 had broken out between the USSR and the USA in 1962, one might have said that the differences between the capitalist and communist worlds made the war inevitable. Yet war did not break out between the USSR and USA, and the battery of attractive-sounding arguments suggesting it was inevitable would be demonstrably false. This is also the case with Thucydides’ famous claim.

This question of historical inevitability can drive one up a wall; proximate causes are inadequate in themselves (“the war became inevitable when Athens and Sparta declared war”), and long term causes only seem decisively fateful with the benefit of hindsight. For this reason, theses about when war became inevitable often say more about the tastes of the author making the claim than the meaningful answer to the question at hand. How, then, is one to approach such a challenge beyond pointing out its puzzling subtext?

Part II: Patterns of Behavior and Ideological Conflict Make Wars Increasingly Likely But Never Inevitable Until They Are Declared: The Peloponnesian War as a Case Study

If a man decides on January 1^st to eat only the gristle of bacon for the rest of his life and has a heart attack after breakfast on June 1^st, one would probably not blame the final breakfast for his demise, or say that the heart attack was inevitably going to take place on June 1^st. The best that one could say is this: given the establishment of a repeated pattern of dangerous behavior, a disastrous result became increasingly likely as the timeline progressed after January 1^st. Although World War 3 did not break out in 1962, such a conflict was probably far more likely at that moment than, say, during the years of the Clinton Presidency. This analogy enriches the possibilities for answering the question “when did the Peloponnesian War become inevitable?” We know that it was only inevitable once it was declared; however, we can also say that after certain points on the timeline, patterns of behavior were established that were sufficient to lethally drive up the likelihood of a conflict between Athens and Sparta.

The remainder of this paper seeks to present two points. First, potentially lethal patterns of behavior were well established before the conflict of 431 BC, making war very likely by that point. Second, ideological conflict between Athens and Corinth on the difference between a subject, an ally, and a colony effectively exacerbated tensions in 431 BC to provide a pretext for the war. The fact remains, however, that it might have been avoided at any time just as the hypothetical World War 3 was avoided, or at least delayed. A diet of gristle does not guarantee a heart attack; it only makes it very likely.

In the same way, we can say that the Peloponnesian War was caused by dangerous patterns of behavior established over time that made disaster more and more probabilistic at every moment (though, emphatically, never inevitable). Oligarchic, conservative, land-locked Sparta was deathly terrified of democratic, innovative, maritime Athens’ growth yet continued to have confidence in the superiority of her land forces. Indeed, confidence in the age-old superiority of hoplite warfare to all other forms of military organization was an inextricable aspect of the Spartan mindset, and the Athenian defeat at Tanagra in 457 and the Egyptian disaster later that decade likely lived on in the collective consciousness of the Greek world for a long time afterward. Thus, Athens simultaneously seemed infuriating and vulnerable to many conservative Spartans. (In On the Origins of War and the Preservation of Peace, Kagan writes that “the Athenians simply did not have enough manpower to create an offensive threat.”) At the same time, Periclean Athens was confident in her Long Walls and the power of her navy and simultaneously committed to an imperialistic policy in the Aegean upsetting the power of Sparta’s allies. Considering the fifty year interval separating the Persian from the Peloponnesian War as a whole, Thucydides was certainly correct when he wrote: “that the whole period…with some peaceful intervals, was spent by each power in war, either with its rival, or with its own revolted allies, and consequently afforded them constant practice in military matters, and that experience which is learnt in the school of danger” (Thu, 1.18). It takes no Thucydides to realize that this was a potential recipe for disaster, with warfare between Athenian and Spartan interests the rule rather than the exception throughout the period. In fact, even before the Battle of Sybota, the Siege of Potidaea, and the ultimatum over the Megarian decree, the people of Corcyra could meaningfully warn the Athenians that war was “all but upon (them)” (Thuc. 1.36).

In such a climate, the Peloponnesian War might have broken out at many points in history. After decades of hostility and memories of many unavenged loved ones dead on the battlefield, war probably seemed very likely indeed by the time of the crisis over Epidamnus in the late 430s. Was there perhaps a point along the timeline in which the probability for long-term peace was at its maximum, or at least significantly greater than by the time of Sybota? My intuition is that the Spartan rebuffing of Athenian aid at Mt. Ithome in 462 BC significantly worsened the climate—perhaps beforehand the conciliatory policies of a man like Cimon might have found some workable middle ground with the Spartan oligarchy. The outbreak of the First Peloponnesian War soon afterward in 460 BC is surely no coincidence, and this too poisoned the waters—once war was declared once, it was significantly more likely that it could happen again in the realm of everyone’s imaginations. Indeed, Athens and Sparta were by some standards still in a theoretical state of war even after the conflict nominally ended: after all, the struggle was concluded by a supposed 30 Years Peace, which is really a euphemism for a ceasefire, not an eternal truce. It was within this volatile atmosphere that two conflicting ideologies concerning the very nature of spheres of influence would prove sufficient to spark a second explosion.

The First Peloponnesian War was an indecisive affair, and Corinthian interests and commercial rivalry with Athens continued to cause great travail. The Peloponnesian League was a loose defensive network led by a hegemon; the Delian League was a network of subjugated states. Corinth, a member of the Peloponnesian League armed with an ancient name and great pretensions, was neither a real hegemon nor the leader of an empire. Desirous of sway in her own right, she seems to have perceived her colonies as more than simply sister cities sharing quaint historical and religious associations, which was otherwise the rule for Greek colonial relations. Athens saw Corcyra as a neutral state free to make its own choices; Corinth did not concur.

Corinth’s grounds for her high expectations for her colonies were, however, shaky—the best the Corinthian representatives at Athens could say about defiant Corcyra was that proper respect was not paid to the metropolis at games and sacred assemblies, which seems less than compelling as grounds for war (Thuc. 1.25). However, the claim that Corinth’s other colonies acquiesced more readily to her will (Thuc. 1.38) and the assertion that Epidamnus theoretically belongs to the Corinthian sphere of influence because she is the daughter of a daughter city (Thuc. 1.25) prove that there existed a unique Corinthian conception of what it meant to be a metropolis. At 1.40, the Corinthians explain that their city supported Athens’ suppression of the Samian revolt because “every power has a right to punish its own allies.” The implication is that Athens should leave well enough alone and let Corinth do what it pleases to Corcyra—however, the secondary implication is that in Corinthian eyes, “ally,” “subject,” and “colony” are interchangeable terms. Of course, one could claim that Corinth was simply grasping at straws because she feared what would happen if Corcyra’s navy joined the Athenian fleet. However, the trouble over Potidaea, an Athenian ally but also a Corinthian colony, suggests that fundamentally, the Corinthians were sincere in their belief that colonial ties implied the existence of sacred spheres of influence, and that defending these rights was worth dying for.

Kagan’s suggestion that “had it not been for Corinth the Spartans would have taken no action whatever” (307) is in harmony with the claim of Elizabeth Meyer that the conservative Spartan state as a rule did not intervene in Athenian affairs, even when Athens established military garrisons (Meyer, 40). Corinth’s power at League meetings was likely very great indeed if the story is true that she once deterred Sparta from supporting Samos and now forced the city’s hand by shaming its leaders as unhelpful and indecisive at the council to decide for war. However, one should not underestimate an independent Spartan willingness to fight. According to some sources, Sparta first considered going to war when Dorcis was rebuffed; it demanded that Athens neglect its walls during Themistocles’ heyday; at 1.101, Thucydides suggests that it nearly went to war with Athens over the issue of rebellious Thasos, and the same situation certainly took place during the Samian revolt; Cimon and his party were rebuffed at Mt. Ithome; the First Peloponnesian War was fought!

Ultimately, Kagan is likely correct when he says that the Corinthians “accepted the division of the Greek world into two parts as a lasting and workable arrangement” (Kagan, 175). However, a fundamental disagreement over just where the borders of those “two parts” were located made conflict with Athens a continuous reality and war with Sparta a very likely attendant outcome. The indecisive conclusion of the First Peloponnesian War sowed dangerous seeds, just as the First World War would in many meaningful ways pave the way for the Second in the 20^th century.

Had the cities of Carthage and Alexandria ultimately fought a “Punic War” in an alternate universe, one could write endlessly of its inevitability: conflicts between Greek and Punic culture, access to the lucrative grain markets of North Africa, and even geographical location could be used to justify such a theoretical conflict. The fact that such factors were not sufficient to even cause diplomatic ripples in our universe proves that history works probabilistically but not fatefully. I maintain that the Peloponnesian War never became inevitable until it was declared. However, repeated conflict over the nature of allies, colonies, and subjects made violent solutions extremely probabilistic, particularly after the outbreak of outright hostilities for the first time in 460 BC. But the ultimate choice for the war—and ultimate blame for it—lies in the hands of the individual statesmen who failed to come up with a more imaginative solution to the problems at hand.