What is Thucydides Trap that Xi warned Trump about?

In his first visit to China in nine years, US President Donald Trump met his Chinese counterpart Xi Jinping as part of a two-day summit in Beijing meant to stabilise bilateral relations and calm economic tensions that had reached a new high during the second Trump administration. In his opening remarks, Xi had one message for Trump. The US must "overcome the Thucydides Trap".

Xi, in fact, used a term that was popularised by American political scientist Graham Allison.

The Chinese president was referencing the ancient Greek historian Thucydides, who wrote about the Peloponnesian war, a 2,400-year-old conflict between the ancient city states of Athens and Sparta for mastery over mainland Greece. The term Thucydides Trap was popularised by American political scientist Graham Allison in 2012 to describe an apparent tendency towards war when an emerging power threatens to displace an existing great power as a regional or international hegemon.

Xi Jinping framed the central question facing both nations as: "Can China and the United States transcend the so-called Thucydides Trap and forge a new paradigm of relations between major countries?"

In essence, Xi’s message was clear: Even as Beijing has grown dramatically closer to matching Washington’s economic and military strength, the US should not view China as an inevitable rival or enemy. Instead, both sides should choose partnership over confrontation, cooperation over zero-sum competition.

WHAT IS THE THUCYDIDES TRAP?

The term Thucydides Trap was popularised by American political scientist Graham Allison in 2012 (and later expanded in his influential 2017 book Destined for War). It draws directly from the writings of the ancient Greek historian Thucydides.

Thucydides authored History of the Peloponnesian War, a detailed account of the devastating conflict fought between two rival alliances: the Delian League led by Athens and the Peloponnesian League led by Sparta. This war lasted 27 years and ultimately weakened both great powers, ending the golden age of classical Greece.

After the Greeks successfully repelled the Second Persian Invasion in 480 BC, Athens and Sparta emerged as the two dominant powers in the Greek world. Athens rapidly transformed into a formidable naval and commercial empire, building wealth, expanding its influence, and projecting power across the Aegean Sea. This shift disrupted the existing balance of power and created deep unease in Sparta, the traditional land-based hegemon.

As Thucydides famously observed: "The growth of the power of Athens, and the alarm which this inspired in Lacedaemon [Sparta], made war inevitable".

Allison used this ancient insight to describe a recurring and dangerous pattern in international relations: when a rising power threatens to displace an established ruling power, the structural stress and fear this creates often make violent conflict very difficult to avoid.

In his research at Harvard's Belfer Center, Allison examined 16 historical cases over the past 500 years, when a rising power challenged the ruling one. In 12 out of 16 cases, the result was war.

Importantly, the Thucydides Trap does not say that war is inevitable between a rising power and a dominant one. Rather, it serves as a warning about the structural pressures that emerge during major power transitions. These pressures are typically driven by the rising power’s growing ambition and desire to reshape the existing international order; and the established power’s fear, insecurity, and determination to preserve its dominance.

THUCYDIDES TRAP AND THE US-CHINA RIVALRY

The concept is frequently applied to modern US-China relations because many analysts see parallels between ancient Athens and Sparta and today’s shifting global balance between Washington and Beijing.

For decades after the Cold War, the US remained the world's undisputed superpower, dominating global finance, military power, technology, and international institutions. China's dramatic economic rise over the last four decades, however, has increasingly challenged that dominance.

Beijing has expanded its military capabilities, deepened its technological ambitions, increased its global influence through initiatives like the Belt and Road Initiative, and become a direct competitor to the US in areas ranging from artificial intelligence and semiconductors to trade and naval power in the Indo-Pacific.

This rapid rise has fuelled growing anxiety in Washington. Successive US administrations, including those led by Trump and Joe Biden, have imposed tariffs on China, tightened technology restrictions, strengthened military partnerships in Asia, and sought to reduce dependence on supply chains originating from Beijing .

Supporters of the Thucydides Trap theory argue that these tensions reflect the classic dynamics of a rising power challenging an established hegemon. China seeks greater influence and recognition commensurate with its power, while the US fears losing its long-held strategic dominance.

Critics, however, caution against treating the theory as destiny. Unlike ancient Athens and Sparta, the US and China are deeply economically interconnected, possess nuclear weapons, and operate within a highly globalised international system. Many argue that these factors create strong incentives to avoid direct military conflict, even amid intense rivalry.

But as far as Xi Jinping is concerned, the message behind invoking the Thucydides Trap is straightforward: instead of viewing Beijing as a rival to be contained, Washington should recognise China as an equal power to engage with.

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