I. Introduction
In his opening remarks at the summit with the US president Donald Trump on May 15, 2026, the Chinese president, Xi Jinping, invoked the fifth-century BC Greek historian Thucydides to issue a veiled warning to Trump.
“The world has come to a new crossroads. Can China and the US transcend the so-called ‘Thucydides Trap’ and forge a new paradigm for major-power relations?”
The Thucydides Trap is a concept originated by Herman Wouk, a novelist and World War II veteran, who used it in his Admiral Raymond A. Spruance lecture, delivered on April 16, 1980, at the U.S. Naval War College. Wouk compared the US-Soviet Cold War to the “Cold War” that developed between Sparta and Athens and once they had defeated Persia, their common enemy, remarking:
“And more than two millennia later we look still trapped in Thucydides’ world. None of the ways in which those quarrelsome Greeks behaved is suited to these dread times of nuclear menace; yet we still behave in those ways, and can find no other. How do we break out of this Thucydidean Trap, which now threatens to strangle, if not to destroy, our world?”
Decades later, the term was then popularized by US political scientist Graham Allison to describe an apparent tendency towards war when an emerging power threatens to displace an existing great power as a regional or international hegemon. The term became widely used in 2015, and mainly applies to analysis of US-China relations.
Supporting the thesis, Allison led a study at Harvard University’s Belfer Center for Science and International Affairs which found that, among a sample of 16 historical cases of an emerging power rivaling a ruling power, 12 cases ended in war.
With this background in mind, this paper aims to analyze the reality of “the Thucydides Trap” and the possibility of a great war between the US and China based on power transition theory.
II. Origin and Definition of “the Thucydides Trap”
The expression “the Thucydides Trap” was inspired by the ancient Athenian historian and military commander Thucydides (died c. 400 BCE), used first in a speech by Herman Wouk in 1980, and then revived by US political scientist Graham Allison around 2011. Wouk described “the Thucydides Trap” as a precedent for the 20th-century Cold War:
You remember that Sparta and Athens were the two great adversaries, the ‘superpowers’ of the Greek world; that they had allied themselves to fight off and defeat a common enemy, Persia; and that after the victory their alliance fell apart in a cold war.
Wouk lamented the recurrence of superpower rivalry, particularly in the nuclear age, but concluded that he found hope in a source. He pointed backward in time from Thucydides to the Biblical age, and specifically to Isaiah’s prophecy:
“And they will beat their swords into plowshares and their spears into pruning hooks, nation shall not lift up its sword against nation, nor will they learn war anymore.”
Seizing on an observation by Thucydides in his History of the Peloponnesian War that “it was the rise of Athens and the fear that this instilled in Sparta that made war inevitable” (or, in the translation by Richard Crawley, “The growth of the power of Athens, and the alarm which this inspired in Lacedaemon, made war inevitable”), Graham Allison used the term to describe a tendency towards war when a rising power (such as Athens) challenges the status of a ruling power (such as Sparta).
Allison expanded this significantly in his 2017 book ‘Destined for War,’ in which he argued that “China and the US are currently on a collision course for war.” Though Allison argues in “Destined for War” that war between a “ruling power” and “rising power” is not inevitable, war may be very difficult to avoid and requires extensive and intensive diplomatic attention and exertion in the case of a “Thucydides Trap.”
For Wouk, the Thucydides Trap is that pending the fulfillment of Isaiah’s prophesy, superpowers will continue to take up arms against each other, leaving the United States to depend on those who “stand in the breach” and “serve.” Despite the sadness of this predicament, Wouk believed that the United States was fortunate in that “[t]here are hundreds of Spruances in this country. And there are hundreds of young Netanyahus in Israel, and in America there are thousands of Butch Williamses.”
For Allison, the term describes the theory that when a great power’s position as hegemon is threatened by an emerging power, there is a significant likelihood of war between the two powers. In Allison‘s words:
“Thucydides’s Trap refers to the natural, inevitable discombobulation that occurs when a rising power threatens to displace a ruling power… the resulting structural stress makes a violent clash the rule, not the exception. ”
To advance his thesis, Allison led a case study by Harvard University’s Belfer Center for Science and International Affairs which found that among 16 historical cases of an emerging power rivaling a ruling power, 12 cases ended in war. The cases included in Allison’s original study are listed in Table 1:
Table 1: Thucydides Trap cases (source: Belfer Center for Science and International Affairs. Harvard Kennedy School. Archived from the original on 5 July 2020)
III. Theories on the possibility of a great war between the US and China
Will the ‘Thucydides Trap,’ as predicted by Thucydides and as argued by Graham Allison, actually lead to a great war between the U.S. and China?
There have been a variety of divided arguments and opinions about the possibility of a great war between the US and China.
First, Liberal scholars generally have the optimistic view that China will rise peacefully and that China will not challenge the US to change the current international order. In other words, an optimistic view on the rise of China is based on the basic idea of liberalism that deepening economic interdependence and growing cooperation and exchange between countries bring prosperity and peace for all countries (Ross, 1997; Johnston, 2003; Friedberg, 2005; Keller and Rawski, 2007; Ikenberry, 2008; Lucenti, 2024).
According to this view, because China has achieved rapid economic growth through international trade and investment, China is a major beneficiary of the current international economic order. As a result, China will comply with international rules and norms and resolve conflicts and disputes through negotiation rather than force. This optimistic view emphasizes that China has actively participated in various international organizations such as the World Trade Organization (WTO) and still pursue economic growth through international trade and investment.
Even some realist scholars, who view the world politics as a zero-sum game in an anarchic international system, side with an optimistic view that China will not challenge the current international order and rise peacefully (Brzeziński, 2000; Riditio, 2015; Jalil, 2019). Realists generally view the rising China as a real threat to the US, but some realist theorists and experts argue that Chinese leaders will not attempt to change the current international order led by the US because in doing so, China will suffer enormous losses and damages under the current US hegemonic system (Gil and O’Hanlon, 1999; Wohlforth, 1999; Freedman, 2012; Tench 2024).
These realists argue that it will be difficult for China to acquire national power and capabilities to challenge the US now or in the near future and that the claim of the “China Threat Theory” is baseless and premature. The core basis for this optimistic view lies in the US’s power preponderance over China. These realists present various economic and military indicators showing that the US hegemony continues and that China’s economy has been stagnant or reversed. Therefore, they claim that the US as the architect of the current international order can restrain China or prevent China from dominating the international system.
Specifically, to borrow Friedman’s argument, China is nothing more than a paper tiger. According to him, first, China is physically quite isolated and cannot easily expand its territory; second, China has never had a powerful naval force to project its power globally for centuries; and last, China is an inherently unstable country, with the majority of Chinese people living inland suffering from poverty, and therefore there are structural limitations to China’s growth (Freedman, 2012).
Brzezinski, who served as the White House National Security Advisor, also argues that China is currently rising peacefully and that a great war between the US and China is neither inevitable, nor likely to occur (Brzeziński,2000, 20). Jalil claims that, contrary to Mearsheimer’s argument, China is unlikely to challenge the US to change the international order. This is because China’s military is much weaker than that of the US and because compared to the US, China has far smaller number of nuclear warheads and lower defense budget (Jalil, 2019, 57-58).
Second, scholars, who view the rise of China as very threating, predict that China will attempt to change the current international order established by the US. This pessimistic view, summarized as the “China Threat Theory,” is mainly raised by realist scholars. Many realists predict that fast-growing China will threaten to change the current international order by challenging the US in the near future.
The pessimistic realists pay attention to China’s provocative behaviors around Taiwan and in the South China Sea and the Senkaku Islands. These realist scholars also emphasize China’s rapid military buildups and values Pursued by the Chinese Communist Party as main threats to Western democracy and rule-based international order. They predict that China will repeat the patterns of behaviors by great powers in history to pursue the hegemonic power.
Especially, offensive realists perceive China as very threatening. For example, Mearsheimer argues that China will seek to dominate Asia just as the US had dominated the Western Hemisphere and that a stronger China, like the US, will have global security interests. He claims that China will attempt to dominate the major sea lanes, as the US emphasized the importance of dominating the world’s major sea lanes. Thus, according to Mearsheimer, China will seek to build a blue-water navy, thereby projecting its power globally and dominating major sea lanes (Mearsheimer, 2014, 492). Allison also sees China as a very threatening challenger, comparing the US-China competition to “the Thucydides Trap” (Allison, 2014, 1).
Rapkin and Thomson argue that the economic interdependence advocated by liberal scholars is not a “panacea” for peacefully resolving conflicts between nations. They insist that no newly rising state has avoided great power wars in its rise to superpower status over the past 500 years and that China is no exception (Rapkin and Thomson, 2006, 334). Roy also predicts that China will seek a hegemonic power in East Asia in the long term. In doing so, unlike Japan, China can easily move large-scale troops, making it much easier to use military force (Roy, 1994, 47).
Moreover, Bernstein and Munro argue that since the 1980s, China has been trying to gain hegemony in the Asia-Pacific region and that the US, which rejects the emergence of a regional hegemon in Asia, will clash head-on with China. They argue that a military conflict between China and the US is quite possible if China attempts to occupy Taiwan by force or if territorial disputes in the South China Sea intensify (Bernstein and Munro, 1997).
Hang argues that in order to reorganize the world order, China currently challenges the hegemony of the US in three areas: economic, military, and soft power. He claims that the US is given four options (accommodation, containment, cooperation, and confrontation) in response to this China’s challenge (Hang, 2017, 17).
The pessimistic views on the rise of China are mainly raised by realist scholars, but they are also raised by some liberal scholars. While the liberalism maintains the position that deepening economic interdependence and growing cooperation and exchange between countries will bring peace and prosperity, some liberal scholars point out that mutual trust between China and Western countries is difficult to attain due to the nature of the Chinese Communist regime and China’s historical and cultural traditions (Shambaugh, 1996, 180).
They insist that China, as a non-democratic authoritarian state, is highly likely to come into conflicts with democratic states like the US. In addition, there are concerns from these liberal scholars that an authoritarian regime like China will appeal to nationalism to overcome its economic downturn and will try to find a breakthrough for the regime by channeling the anxiety and frustration of their people to foreign countries, such as Taiwan or the US (Whiting, 1995).
Third, Graham Allison’s argument
The Thucydides Trap, popularized by Graham Allison in the early 2010s and expanded in his 2017 book “Destined for War”, draws on the ancient Greek historian’s account of the Peloponnesian War. Allison claimed that when a rising power challenges an established one, structural pressures make conflict probable and applied this lens to the US–China rivalry, warning that the two countries were on a “collision course.”
Fourth. Power transition theory and a choice-theoretic model
There is a view that the peaceful rise of China depends on whether or not certain conditions are met. This view is argued mainly by two theories: power transition theory and choice-theoretic model.
Power transition theory, created by Organski and later developed by scholars such as Kugler and Lemke, is a realist theory, but does not take a specific position on whether China will rise peacefully or challenge the US to change the current international order. Instead Organski argues that a rising great power challenges the dominant nation to change the global order when the rising state achieves power parity with the current hegemonic state and when the rising challenger is dissatisfied with the current international order established by the hegemonic state (Organski, 1958, 338).
In other words, China, which is dissatisfied with the current international order established by the US, will challenge the US in order to change the international order when China reaches power parity with the US. At that point, a great war between the US and China will break out. However, according to the power transition theory, even if China reaches power parity with the US, China will not challenge the US in order to change the existing global order if China is satisfied with the current international order.
On the other hand, according to a choice-theoretic model, a great war occurs only if the rising challenger is willing to fight with the hegemonic state by taking risks (Morrow, 1985; Bueno de Mesquita and Lalman,1986; Kugler and Zagare, 1990;Kim and Morrow, 1992).
Organski is silent on the question of risk attitudes of the rising great power. Kugler and Zagare discussed the effect of risk attitudes on power transitions between nuclear powers. They conclude that war can occur only when one power is risk-acceptant and the other is risk-neutral or risk-acceptant (Kugler and Zagare, 1990, 255).
Kim and Morrow agree with Kugler and Zagare that risk-acceptant rising states make war more likely. Kim and Morrow assert that power shifts are more likely to lead to a great war as the challenger becomes more risk-acceptant, the declining state more risk-averse, and the rising state’s dissatisfaction with the status quo increases (Kim and Morrow, 1992, 896).
On the other hand, Maoz argues that the outcomes of disputes are decided by the balance of motivation and resolve among countries in armed conflicts; that is, the country with the highest level of resolve is more likely to win. Maoz finds that capabilities are not related to the results of disputes, while resolve variables are consistently related to the outcomes of disputes. The implication is that countries with higher levels of resolve are more likely to initiate wars (Maoz, 1983).
IV. The possibility of a great war between the US and China
1. Overview
This paper introduced various theories on the possibility of a great war between the US and China. By using power transition theory, this paper aims to analyze which view is valid on whether or not China will rise peacefully and challenge the US in order to change the current international order. This is because, fundamentally, the power transition between the US and China plays a decisive role in a great war between the US and China, and the power transition theory is the primary theory dealing with such power transitions.
From the perspective of power transition theory, the conditions for China’s peaceful rise (no outbreak of a great war between the US and China) are as follows: First, the US must maintain its superiority in power over China to prevent China from attempting to alter the current international order. Second, China must be satisfied with the current international order, that is, maintaining the status quo.
Based on this explanation, this paper seeks to explore the possibility of China’s peaceful rise by verifying the validity of the following two conditions: (1) the US maintaining its superiority in power over China; (2) China’s satisfaction with the current international order.
2. Comparison of Economic, Military, and Technological Power Between the US and China
According to power transition theory, for a great war to occur between the US and China, their power must become equal. As long as the US maintains its preponderance in power over China, it is difficult for China to dare challenge the US., and thus a great war does not break out. Therefore, this paper aims to measure and compare whether the US maintains its superior power over China in three areas: economy, military, and technology.
a. Comparison of economic power between the US and China
GDP is commonly used to compare the economic power between nations. As shown in Figure 1, the US maintains an overwhelming advantage over China in nominal GDP and GDP per capita.
Figure 1: Comparison of USA and China in terms of economic and social power indicators (source: https://www.statspanda.com/blog/usa-vs-china-comparison). Red: USA; Blue: China
Figures 2 and 3 also show that the US is significantly ahead of China in nominal GDP. Figures 2 and 3 show that the US’s economic superiority over China will continue even in 2030.
Figure 2: Gross domestic product (GDP) at current prices in China and the United States from 2000 to 2025 with forecasts until 2030 (source: Statista)
Figure 3: US (upper line, turquoise color) & China (below, brown color) GDP Trend, 1980-2030 (Current billion US dollar) Source: IMF data.
b. Comparison of military power between the US and China
As shown in Table 2, to compare the military power of the US and China, this paper utilizes Global Fire Power data, which surveys the military capabilities of 145 countries worldwide annually. Since a military conflict between the US and China is highly likely to occur in the Taiwan Strait or the South China Sea, this study focuses on the naval and air powers of both nations. Unless a great war breaks out between the US and China on mainland China, a comparison of the two countries’ armies is of little significance. There is almost no possibility of a great war breaking out between the US and China on mainland China.
As Table 2 shows, China significantly surpasses the US in population and the number of active-duty soldiers, but these indicators are of little significance unless the two nations engage in combats inside China. A military conflict between the US and China is highly likely to occur in the Taiwan Strait or the South China Sea, and consequently, the outcome will be determined by the disparity in naval and air power between the two nations.
Except for total population, the number of active-duty soldiers, and tank holdings, the US leads China in almost every military indicator. In particular, the US holds an overwhelming advantage over China in air power, including aircraft, fighter jets, attack aircraft, and helicopters. The total number of US aircraft is nearly three times that of China.
The US also surpasses China in naval power, including aircraft carriers, helicopter carriers, and destroyers. Although China has recently acquired three aircraft carriers, they are diesel-powered rather than nuclear-powered, placing it at a significant disadvantage compared to the US, which possesses 11 nuclear-powered carriers. Although China maintains an overwhelming advantage over the US in frigates and patrol vessels, these ships do not play a significant role in determining the outcome of the great war between the US and China, where massive military assets are expected to be fully mobilized. The US also surpasses China in submarine possession.
Furthermore, while China is estimated to possess 600 nuclear warheads in 2026 after significantly increasing its stockpile in recent years, this falls far short of the US which holds over 5,000 warheads.
Moreover, the US significantly outperforms China in defense spending and oil production, which has a major impact on the warfighting capabilities of both nations. The US defense budget for 2026 is projected at $831 billion, overwhelming China’s $303 billion. China also cannot match the US in terms of oil production, which is used for weapons such as fighter jets and tanks.
Table 2: US-China Military Power Comparison (Unit: number) (Source: Global Fire Power, 2026)
c. Comparison of technology power between the US and China
First, in order to compare the technology power between the US and China, this paper compares the investment amounts of companies from both countries in nine major emerging technology sectors shown in Figure 4.
In these nine emerging technology sectors, R&D investment by US companies is much higher than that of Chinese companies. From 2014 to 2024, the share of US companies in global R&D investment across nine high-tech industries increased by 10 percentage points, from 42% to 52%, while the investment amount rose from $270 billion to $675 billion. In contrast, the market share of Chinese companies increased by 9 percentage points from 4% to 13%. And while Chinese firms’ investment grew from $26 billion to $165 billion, the gap in investment between the two countries remains significant. (See Figure 4)
Figure 4: Number of companies investing in R&D by industry in the U.S. and China in 2024 (Figures in parentheses represent global totals)
Moreover, the US surpasses China in the fields of AI and semiconductors, which are currently receiving the most attention. According to Morgan Stanley, US companies are expected to invest $109 billion in artificial intelligence (AI) in 2024 alone; this figure is nearly equivalent to the combined AI investment of all other countries worldwide, placing the US at the forefront of global AI investment.
In addition, the US has released twice as many notable AI models as China, including OpenAI’s ChatGPT, Google’s Gemini, and Meta’s Llama. DeepSeek is arguably the most prominent AI model in China.
The US also holds the upper hand in the semiconductor sector; thanks to NVIDIA’s CUDA software platform, US-made chips outperform Chinese chips. However, both countries rely heavily on Taiwan for nearly 90% of the advanced chips needed for AI development.
On the other hand, the sector where China is experiencing rapid growth is electric vehicles. Nearly half of the new cars sold in China in 2024 were electric vehicles, a figure that compares to the proportion of electric vehicles in the US (approximately 10%) from 2009 to 2024.
Furthermore, the Belfer Center at Harvard University measured the rankings of 25 countries worldwide in key and emerging technology fields such as AI, biotechnology, semiconductors, space, and quantum technology; as shown in Figure 5 and Table 3, the US was found to be far ahead of China.
Figure 5: Evaluation indices and rankings of 25 countries worldwide in five key technology fields including AI, Biotechnology, Semiconductors, Space, and Quantum Technology (Source: Belfercenter, Harvard University, USA)
The US recorded 84.3 points across five core technology fields – AI, biotechnology, semiconductors, space, and quantum technology – significantly outpacing China, which scored only 65.6 points. In particular, as shown in Table 3, the US significantly outperformed China in AI with 22.7 points compared to China’s 14.5 points, in semiconductors with 26.4 points versus 22.1 points, and in the space sector with 13.8 points versus 8.4 points.
Table 3: National power of 25 countries across key technology sectors: Artificial Intelligence, Biotechnology, Semiconductors, Space, and Quantum. (Source: Belfer Center for Science and International Affairs. Harvard Kennedy School, 2025 June).
3. Satisfaction of China with current international order
According to power transition theory, in order to rise peacefully, China should be satisfied with the current international order established by the US. There are various ways to measure whether and how much a rising challenger is satisfied with the current international order established by the dominant nation. Power transition theory proposes two measures. One measure is the alliance portfolio. That is, the more similar (different) the alliance portfolio of the rising challenger is to the alliance portfolio of the dominant nation, the more satisfied (dissatisfied) the challenger is with the global order established by the hegemonic power.
Therefore, in order to measure whether and how much China is satisfied with the current international order, this paper compares the member states of the Shanghai Cooperation Organization (SCO) and the member states of the North Atlantic Treaty Organization (NATO) because China has been a leader of the SCO and the US has been a leader of NATO. Unlike NATO, the Shanghai Cooperation Organization is not a military alliance or a security organization. However, because the Shanghai Cooperation Organization has been strongly opposed to NATO and because the SCO has recently expanded its activities to include military activities such as increased military cooperation, intelligence sharing, and counterterrorism, this paper compares alliance portfolios of NATO and the SCO for the convenience of analysis.
The Shanghai Cooperation Organization had six member countries (China, Kazakhstan, Kyrgyzstan, Russia, Tajikistan, and Uzbekistan) when it was formed in 2001. Then India and Pakistan joined the SCO in 2017, followed by Iran in 2023 and Belarus in 2024.
Founded in 1949, NATO started out with 12 member states: Belgium, Canada, Denmark, France, Iceland, Italy, Luxembourg, the Netherlands, Norway, Portugal, the United Kingdom, and the US. Since then, Greece and Turkey joined NATO in 1952, followed by West Germany in 1955, Spain in 1982, Hungary, Poland, and Czech Republic in 1999, Bulgaria, Estonia, Latvia, Lithuania, Romania, Slovakia, and Slovenia in 2004, Albania and Croatia in 2009, Montenegro in 2017, North Macedonia in 2020, Finland in 2023 and Sweden in 2024.
It is very surprising that there is no single country that belongs to both the SCO and NATO. Because the alliance portfolio of China, a rising challenger, is completely different from that of the US, the dominant nation, this paper claims that China is 100% dissatisfied with the current international order led by the US.
The second way to measure whether and how much a rising challenger is satisfied with the current international order established by the hegemonic power is to examine to what extent the challenger increases its military spending. Werner and Kugler argue that a rising contender dissatisfied with the international order established by the dominant nation makes a significant effort to increase its military spending to change the global order. They claim that when defense spending of the challenger exceeds that of the dominant nation, the risk of a great war will increase (Werner and Kugler, 1996, 191).
In order to investigate whether and how much China increased military spending, this paper utilized defense expenditure data published by the World Bank, the Chinese Ministry of Finance, and Statista to investigate whether China’s defense spending has increased. As shown in Figures 6 and 7, China has continuously increased its defense spending since 1990, with a particularly significant rise since 2010. Therefore, this paper argues that China is dissatisfied with the current international order established and led by the United States.
However, as shown in Figure 7, China’s defense spending has shown a declining trend in terms of the magnitude of the increase in the defense budget since 2014, and as shown in Figure 8, the ratio of China’s defense spending to GDP has generally decreased after peaking at 2.45% in 1990. Consequently, it is difficult to conclude that China’s defense spending has increased based solely on the magnitude of the defense budget increase and the ratio to GDP, and thus it is difficult to conclude that China is dissatisfied with the current international order.
Nevertheless, if we assess China’s dissatisfaction with the current international order based on its total defense spending, it can be argued that China is highly dissatisfied with the current international order.
Figure 6: Estimated expenditure on the military in China in current prices from 1990 to 2024 (source: Statistica)
Figure 7: China’s defense budget, 2013-2026 (source: CSIS & ChinaPower)
Figure 8: China’s Military expenditure (% of GDP), 1989-2024 (source: World Bank)
The explanations so far can be summarized as follows:
First, China exhibits a significant inferiority in power compared to the US in terms of economic, military, and technological strength. Therefore, according to power transition theory, the US maintains its power superiority over China, making the possibility of a great war between the US and China low. This is because it is unreasonable for China, which is clearly at a disadvantage in terms of power – particularly military power – to dare to challenge the US and engage in military provocations to alter the current international order.
However, judging by the fact that the alliance portfolios of the US and China are completely different, it is true that China is highly dissatisfied with the current international order led by the US. Furthermore, judging by the continuous increase in defense spending, it is also true that China is dissatisfied with the current international order. Therefore, while China likely has a strong desire to change the current international order, realistically, given the significant power gap with the US, China might wait for the opportune moment to challenge the US while maximizing its strength.
V. Conclusion
This paper aimed to analyze the reality of the Thucydides Trap and the possibility of a great war between the US and China based on power transition theory. In doing so, this paper introduced theories on the possibility of a great war between the US and China and analyzed such a possibility.
This paper compared economic, military, and technological power between the US and China and demonstrated that the US is far ahead of China in terms of all three powers. However, this paper showed that China has been dissatisfied with the current international order led by the US.
As a result, while China has a strong desire to change the current international order, realistically, given the significant power gap with the US and China, it is likely that China will wait for the opportune moment to challenge the US while maximizing its strength.
References
