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Re-thinking of the “Thucydides’s Trap” Argument
Views:120 Updated:2020-03-18

Thucydides, who lived in ancient Greece around 2500 years ago, is the author of History of the Peloponnesian War, which recorded the conflicts between the two Greek city-states Sparta and Athens. Thucydides’s work set the foundation of the realist tradition.

The most well-known argument in Thucydides’s masterpiece is that the root cause of the great conflict between Athens and Sparta was the rising of Athens and the fear this caused in Sparta.

In other words, Athens and Sparta were caught in a security dilemma or security trap, which, as many have thought, made the war inevitable. Some also name the security trap as “Thucydides’s Trap”.

To argue for the inevitability of the war between the two Greek city-states, experts have intended to use a scenario of “Prisoner’s Dilemma” to depict the security dilemma faced by the two powers.

Here is a possible scenario of “Prisoner’s Dilemma” - two criminal suspects jointly committed a crime, were arrested and put into two different cells by the police. To make a fair charge, the police needs to get enough information from them. The amount of information uncovered would directly lead to three possible results: If the two suspects all stay in silent, both of them would possibly get a lighter punishment; if one of them stays in silent while the other uncovers the criminal information, the one keeping in silent would be more heavily charged; if  both of them choose to uncover their deeds, they would get equally heavy punishment. What is most likely to happen, under the condition that there should be no chance of communication between the two, is that both of them would attempt to cheat on the other in order to get a lighter punishment. Therefore, the two prisoners finally are trapped in a security dilemma, and this kind of dilemma cannot be overcome.

By linking the scenario of “Prisoner’s Dilemma” to the security situation faced by two states, an ultimate conflict between two states, as many may have maintained, would be inevitable.

The purpose of this analysis is to re-think of the “Thucydides’s Trap” argument, to assess whether it is appropriate to put an analogy between two states and two prisoners concerning the dilemma faced by the two different groups, and to further extent, try to understand the “Thucydides’s Trap” argument in today’s world, and whether and how it could be possible for state actors to surpass it. 

To answer the above questions well, this piece assumes that the fundamental issue is to begin by re-checking briefly of what had happened 2500 years ago during the Peloponnesian war among the Greek city-states, through which, to see whether there could be any limits and defects in Thucydides’s assessment on the root cause of war.

1. The Issue of “Fear” & The Root Cause of War

Thucydides argued that the rising of Athens and the fear it caused in Sparta made the conflict between them inevitable. This assessment would respectably propose a view that if there was a fear within Sparta by then, the same fear was also existed inside Athens, as both powers wanted to maintain a balance of power among the Greek city-states, and they were afraid of losing that balance. A typical example to show Athens’s fear of losing that balance was of its final decision in joining the Corcyra’s side against Corinth,1 because of Athens’s fear of the balance of power turning into a situation against it, in case it failed to check Corinth and let the Corinthians take over Corcyra’s navy. 2

Besides that, according to Donald Kagan’s argument cited from Professor Nye’s work Understanding International Conflicts, Sparta was more fearing of war and of a slave revote than of the growing Athenian power, as 90% of Sparta’s population were slaves, and a revote within Sparta had recently taken place in the year of 464 B.C. 3

Thus, Thucydides’s argument on the root cause of war didn’t seem to be adequate. There should be more than just fear behind the conflicts between Athens and Sparta.

To better understand the cause of the Peloponnesian war, a list of historical events having briefly recorded the rising and breaking down of Athens are worth noticing here.4

·        After around a half-century of war between Greece and Persia, in 449 B.C., Athens and Sparta and other Greek city-states jointly defeated the Persian power. Then Athens had enjoyed a long period of relatively peaceful time for developing itself; with the growing strength of it, Athens and other series of Greek city-states formed the Delian League; around the same period, Sparta and a number of city-states surrounding it also established a defensive alliance;

·        In the year of 461 B. C., the first Peloponnesian war erupted, resulted mainly by the growing tension between Athens and other city-states within the Delian League, as Athens had pressed them to pay taxes in exchange for receiving Athens’s protection;

·        In 445 B.C., the war between Athens and others was ended and followed with a 30-year truce;

·        In 431 B.C., Athens ignored Sparta’s ultimatum, broke the truce made previously, and the second Peloponnesian war was broken out;

·        In 421 B.C., another truce was signed between Athens and Sparta;

·        In 413 B.C., Athens took its most serious adventure to attack Sicily, which had close linkages to Sparta; a conflict was unleashed between Athens and Sparta, and it was ended with a huge defeat of Athens; after then Athens had never re-gained its strength;

·        After the defeat of Athens in 413 B.C., a series of conflicts had been followed between Sparta and Athens; Athens had suffered more defeats;

·        In 404 B.C., Athens was forced by Sparta to sue for peace; the Athenian power was broken down.

From the above list of reviews, it is not difficult to see that the cause of war was more of a subjective matter than of an objective issue. After having enjoyed a certain period of peaceful growth, Athens became the most powerful empire among the Greek city-states. It was not forced by others to go to war, obviously most of the conflicts had been initially launched by Athens, and for a number of occasions, it had broken the truce signed with other city-states.

Prof. Nye well assessed the cause of war between Sparta and Athens from three layers – the precipitating cause, the domestic situation and policies taken, and the external structure. While generally agreeing with some of his points, this analytical piece would tend to understand this issue from both subjective and objective perspectives, and also like to assume an alternative view that the subjective choice made by Athens had played a dominant role, compared to other number of factors including the domestic situation and the external environment, in leading to the breaking out of war. In other words, the war, in the case between Sparta and Athens, was decided more by internal subjective choice than by external objective situation.

The subjectivity of war firstly lied in the aggressive and imperial ambition of the Athenian empire and in the pride of the Athenians in their social system, which made Athens not be afraid of taking adventures toward war. They believed that they were bound to prevail in the conflict with Spartans. As Prof. Nye’s wrote, “The Athenian mood was one of imperial greatness, with pride and patriotism about their city and their social system, and optimism about how they would prevail in the war.”5

Secondly, the subjective nature of the conflict was also contributed by the leadership of Athens. Pericles, the Athenian leader, favoured a war, and was most ready to take risks for war, as he believed that the war with Sparta was inevitable.

Thirdly, the subjectivity of war can be illustrated by the fact that even by the time when the external situation wasn’t in Athens’s advantage, it still didn’t stop it from having taken further adventures against others. For instance, before the outbreak of the second Peloponnesian war, the balance of power structure among the Greek city-states seemed to have gradually turned into a challenging situation against Athens, mostly due to Athens’s improper handling of its relations with other smaller city-states, they got irritated by Athens’s aggressive policies, and some of them including Megara and Potidaea joined the Spartans’ side after the war erupted. Nevertheless, even when the external situation wasn’t in favour of Athens, instead of adjusting its position, it decided to take adventures.

Athens could have more choices apart from having gone to war. Nevertheless, it still had decided to take the most dangerous approach on a number of occasions. Therefore, the war was more of a matter subjectively chosen by Athens, than of an objective matter, under which, Athens was seemingly forced by the external balance of power structure to go to war.

There was a claim made by the Athenians to the Melians during the Peloponnesian war that “the strong do what they the power to do and the weak accept what they have to accept”,6 which could probably have told the whole story behind the root cause of the Peloponnesian war.

2. “Prisoner’s Dilemma”, Two Prisoners, and Two States

Some especially those holding a realist proposition may tend to use the security dilemma faced by two prisoners to depict the difficult situation encountered by two states. This assessment would maintain that this kind of analogy could be misleading to statesmen and policy-makers, and it is not appropriate to put such an analogy between this two groups given the different nature and characteristics between state actors and individuals.

In accordance with the “Prisoner’s Dilemma” logic, the situation faced by two prisoners would only lead a deadlock, and there would be no further way out for them. If statesmen are misguided by this type of logic, they would tend to believe in the inevitability of a conflict, then a war, as what had happened in history on a number of occasions, would most likely come to them. Once decision-makers believe in the inevitability of war, very likely they would give up their efforts to seek other means to solve the problem, and the only major concern left to them should be the preparedness for war and the different timing of war.

In reality, the dilemma faced by two prisoners, in contrast to the situation encountered by two states, should be much more difficult for the prisoners to overcome, if this issue can be analyzed from a relative perspective.

The case of two individual prisoners is of a matter relating to domestic politics, while the relationship between two states is of an issue dealt with by international politics. In the domain of domestic politics, there is the law and government above the individuals, while in the arena of international politics, the international system is anarchy, there is no authoritarian government above the states. The difference remained between domestic politics and international politics in terms of their functions would directly lead to different results when thinking of the security dilemma faced by states and by individuals.

For the two individuals, they are certainly not allowed to challenge the law to negotiate with the police about the nature of the crime or about how many years they could possibly be staying in prison. These factors should be decided by adhering to the law. Besides that, it is impossible for the two prisoners to communicate with each other in any means. Under this circumstance, the choices faced by them could include telling the truth to the police, lying, or keeping silent - telling the truth here also means prisoners’ attempt to cheat on each other, since both of them generally don’t trust the fact that the other would stay in silence. Lying most likely cannot work, as it is impossible for the two prisoners, without any communication, to lie the same to the police. Staying silent is also unlikely, as already pointed, the two prisoners have basically no trust to each other. Thus, the only choice left for them is to tell the truth.

In the case of a security dilemma encountered by two states, international anarchy could be a constraint for states somehow, as under the anarchic system, states may perceive each other more from pessimistic perspectives and tend to be suspicious of others’ intentions, as realists generally believed.

However, anarchy doesn’t mean completely fragmentation and disorder. At both regional and international levels, besides states, there are international law, norms, rules and mechanisms, as well as a variety of transnational organizations, groups, and agencies having been joining in the process of improving the international system. With the growing role of these types of actors in regional and international affairs, the negative effects of anarchy have been relatively reduced. The anarchic international system with the participation of non-states actors have provided sates with alternative channels or platforms to handle the security dilemmas met by them.

Once two states are trapped in a security dilemma, they have more choices than prisoners. They could have more freedoms and leeway to act to get them out of the deadlock. For instance, one of the states could choose to directly approach the other through diplomatic or non-diplomatic channels, or they could get a third party to be involved to play a mediating role. Over all, the most noticeable advantage for states in contrast to prisoners in facing the security trap is that states can communicate and have the rights and capacity to negotiate in any ways as far as they would like to make an effort over this.

In addition, individuals compared to states are in a much more vulnerable position in both physical and mental terms. For example, if one of the two states cheated on the other, another one could in response deploy a number of means– retaliating by playing “tit for tat” games, suing the issue to international law, getting a third party to mediate, or applying any other political and economic means. Apart from that, states can afford to make small mistakes in line with their capabilities as far as they are able to correct the mistakes, shift their behavior and policies to the right direction as quick as they can, and then more severe consequences can be avoided and resilience can be restored after all. However, the timing and chances for making further mistakes by prisoners, once they are taken into prison, should be very limited, unless they would want to bear more severe punishments.

Therefore, the security dilemma for two prisoners should be something which is very hard for them to surpass, while the security dilemma for two states should be an issue that can be handled and overcome by state actors. It is not appropriate to take the security dilemma encountered by states and by prisoners to a parallel position to understand. Statesmen and policy-makers should avoid being misled by the “Prisoner’s Dilemma” logic.

3. Understanding the “Thucydides’s Trap” Argument in the New Era

This session will tend to examine how states could overcome the “Thucydides’s Trap” in today’s world. This can be assessed from both objective and subjective means.

From the objective perspective, the world today is not the one that Thucydides’s had ever lived. When Thucydides wrote History of the Peloponnesian War, the author’s thinking was constrained by history, geography, and technology, as well as by the progress in political, economic and social spheres in general. In modern times, a great deal of changes and advancement in a wide variety of sectors have occurred and they created preconditions to make states feel more difficult to go to war.

People living in Thucydides’s days and even in the past recent centuries were no need to deal with non-security challenges such as climate change, natural disaster, pollution and so on, as faced by humans living in today’s world. People and the societies by then were separated by borders and had limited interactions among them. There were no issues related to terrorism, drug trafficking, and other kind of transborder crimes.

However, starting from the second half of last century, with the development of information technology, and with the invention of other series of advanced technologies in different industries, the world has gradually turned into a more globalized society, and people and countries have never been as closely connected as they are today.

Nuclear weapons, international rules, norms, and mechanisms, the established regional and international organizations and institutions, and the growing participation of other type of non-states actors in international affairs have played tremendous parts in constraining states from taking extreme actions under difficult situations.

From the subjective perspective, whether being able to avoid or overcome the security trap very much depends on the subjective thinking and actions taken by decision-makers. The most crucial issue for them is to avoid being further misguided by the “Prisoner’s Dilemma” logic, as already suggested in the previous session of this analysis.

In retrospect of what had happened in history, in most cases wars had been subjectively chosen by states, rather than the other way around that states had been chosen by wars. There might be exceptional cases over such claim – A state could be forced into war. It decides to get into war because of being attacked in the first place, and going to war is acted as a matter of self-defense. If this is the case, the state is chosen by war.

The final point this analysis would like to make is that in case two states fail to surpass a security dilemma and a war between them is unleashed, states should avoid once again being dragged into the same logic by linking the war with the “Thucydides’s Trap” argument, as many experts and politicians have done before. There is a necessity for them to see that going to war should be a manifestation of states having subjectively given up other means to get themselves out of the security dilemma. After all, it is still of a subjective and epistemological issue for policy-makers.


The first session of this piece, after having assessed the “Thucydides’s Trap” argument, reached a point that the security trap argument was inadequate in interpreting the root cause of war between Sparta and Athens, as it had obviously overestimated the role of the objective matter – the rising of Athens and the fear it caused in Sparta – in deciding the outbreak of the war, while having underestimated Athens’s subjective choice in sparking the conflict. The second session on the “Prisoner’s Dilemma” logic made a point that the security dilemma encountered by state actors and by prisoners cannot be put into a parallel position to understand, given the different nature and severity of the security situation faced by the two groups. Then a concluding point made by the second session was that the security trap can be very hard for prisoners to overcome though, it could be surpassed by states. The final session re-affirmed the points made by the previous two sessions and examined how the objective and subjective factors in today’s world have actually created conditions to complement states’ efforts in surpassing the security traps encountered by them.


1.      Both Corcyra and Corinth were city-states in ancient Greece.

2.      See Nye, Joseph. (2000). Understanding International Conflicts: An Introduction to Theory and History (Third Edition). pp.13. LONGMAN: An imprint of Addison Wesley Longman, Inc.

3.      Ibid. pp.17. Also see Kagan, Donald. (1969). The Outbreak of the Peloponnesian War. NY: Cornell University Press.

4.      Information related to the list of historical events having recorded the conflicts among the Greek city-states is mainly from Nye’s Understanding International Conflicts.

5.      Ibid. pp.14.

6.      Cited from Nye’s Understanding International Conflicts. Also see Thucydides. (1972). History of the Peloponnesian War. pp.55. London: Penguin.

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