The Thucydides Trap and the Rise and Fall of Great Powers

By Jacek Bartosiak

Roughly 2,400 years ago, Thucydides, a Greek historian and author of “History of the Peloponnesian War,” expressed a view that resonates in strategic thinking to this day. He argued that the real cause of the Peloponnesian War was the rapid increase in the power of Athens and the fear this aroused in Sparta, which had dominated Greece thus far. Author Graham Allison used this concept in his book “Destined for War,” in which he described the relationship between the U.S. and China as an example of the “Thucydides trap” – the idea that the decline of a dominant power and the rise of a competing power makes war between the two inevitable.

Thucydides focused his writings and analysis on the structural tensions caused by a sharp change in the balance of power between rivals. He pointed to two main factors that contribute to this change: the aspiring power’s growing need for validation and its demand, either implicit or explicit, for a greater voice and strategic place in multilateral relations; and the current power’s fear and determination to defend the status quo.

In the fifth century B.C., Athens emerged as a powerful force that in mere decades had become a merchant maritime power, possessing financial resources and wealth but also reaching primacy in the Greek world in the fields of philosophy, history, literature, art, architecture and beyond. This irritated the Spartans, whose state had been the dominant land power in Greece throughout the preceding century.

As Thucydides argued, Athens’ behavior was understandable. With its rising power, its confidence also increased, as did its awareness of past injustices and determination to right the wrongs that were committed against it. Equally natural, according to Thucydides, was the behavior of Sparta, which interpreted Athens’ behavior as ungrateful and a threat to the system that Sparta had created and under which Athens was able to emerge as a great power. This combination of factors resulted in structural tensions and, subsequently, a war that devastated Greece.

In addition to the objective shift in the balance of power, Thucydides drew attention to Spartan and Athenian leaders’ perception of the situation, which led to an attempt to increase their own power through alliances with other countries in the hope of gaining a strategic advantage over their rival.

The lesson that Thucydides taught us, however, is that alliances are a double-edged sword. When a local conflict between Kerkyra (Corfu) and Corinth broke out, Sparta felt that, to maintain the balance, it needed to help its vassal, Corinth. The Peloponnesian War began when Athens came to Kerkyra’s defense after Kerkyra leaders convinced the Athenians that a de facto war with Sparta was already underway. Corinth also convinced the Spartans that, if they did not attack Attica, they would be attacked by Athens themselves. Corinth accused the Spartans of misunderstanding the gravity of the threat to maintaining a favorable balance of power in Greece. Although Sparta ultimately won the Peloponnesian War, both Athens and Sparta came out of the 30-year conflict in ruins.