Apologies for the length of my introductory post on Thucydides. This next one is a lot shorter and requires much less setup.
I’m too lazy to rifle through 800 pages for the relevant quote, but I seem to recall that somewhere in his landmark work Diplomacy Henry Kissinger argued that the global order of the Cold War era was more stable than people realized — indeed, more stable than the global order of the early 90s. That’s because a bipolar world is one in which states tend to gravitate towards one of two massive powers. Contrast that with pre-WWI Europe, a multipolar order maintained by a tangled network of alliances. That network is what allowed the chain reaction which turned a regional conflict into a continent-wide slaughter. A Cold War scenario lacks those complications; there are still wars, but they don’t go global.
On a superficial level, Greece circa 435 BCE looks a lot like the world of the Cold War and not very much like pre-WWI Europe. You’ve got two great powers, roughly evenly matched, and the vast majority of the other Greek city states are allied with either one or the other. Two states as strong as Athens and Sparta are inevitably going to compete with one another — as the USSR and the US did — but not on a scale that would sink the rest of the city states into conflict.
Of course, we all know how that turns out. Because as much as Ancient Greece looks like a bipolar order, it’s a lot more tangled and porous than you would expect. Case in point: Potidae.
Potidae is officially an Athenian client state, but they also have deep ties to Corinth. And while Corinth and Athens theoretically have a treaty, they just finished fighting a massive naval battle over the city-state of Corcyra. To make matters worth, Corinth is a member of Sparta’s Peloponnesian League.
By now you should see how the dominoes are stacked. And the next one to fall is Potidae. The Athenians, not wanting the Potidaeans to defect to Corinth’s side, order them “to raze the wall on the Pallene side of the city, to give hostages, to dismiss the Corinthian magistrates, and in future not to receive the persons sent from Corinth annually to succeed them.” When Potidae demurs, Athens sends a military force. But by using the stick instead of the carrot, they only hasten Potidae’s switch over to Team Corinth.
So all of a sudden the Athenians and Corinth (and Corinth’s ally Macedonia) are fighting a war over the whole region surrounding Potidae. And while that’s going on, Corinth goes to Sparta to urge that they get involved as well.
Back in February the foreign policy scholar Walter Russell Mead argued that Thucydides — long considered the patron saint of the realist school — was in fact anti-realist in very fundamental ways. He wrote:
Realism in political science is often tied to the idea that the behavior of states is determined by the structure of the international system and the balance of forces within it. In a famous analogy, realist theory takes states as “billiard balls” knocked about the geopolitical pool table by impersonal and predictable forces. Another analogy calls them “black boxes”; the analyst of international relations doesn’t need to know what is going on inside the black box in its domestic politics in order to understand what the box is doing.
If we define realism this way, then Thucydides isn’t a realist. In fact, he’s the greatest possible enemy of this kind of theoretical realism. He mocks it, spits in its face, and gleefully dances on its grave.
For Thucydides, the internal politics of a state are crucial to understanding and anticipating the policies of that state. Sparta has a set of interests that are not dictated by the nature of the international system so much as by the structure of Spartan society.
And in fact that’s exactly what we see when Corinthian emissaries demand a formal declaration of war from the Spartan assembly. King Archidamus of the Spartans urges caution, suggesting that his countrymen should prepare for war while delaying it further. If Sparta were a simple tyranny like some of its neighbors, he could just make it so, and we might remember the Peloponnesian War very differently. But he must defer to the assembly — the masses — and they vote for war, “because they feared the growth of the power of the Athenians, seeing most of Hellas already subject to them.”
And just like that we’re in the midst of the Peloponnesian War proper.