【9月28日】 米中首脳会談での成果と課題、AIをSIと言い換えも合意

Background and Overview

The U.S.-China summit concluded on September 24, 2026, marking the first in-person meeting between U.S. President Donald Trump and Chinese President Xi Jinping (習近平) in roughly four months — since Trump's visit to Beijing in May. The agenda was unusually broad: Middle East tensions, longstanding trade disputes, the Taiwan situation, and AI regulation all featured prominently in the discussions.

Just before the summit, Iran had presented the United States with a conditional proposal for lifting the blockade of the Strait of Hormuz. Trump told reporters on September 26 that he would not accept it, signaling that energy-related tensions remained very much alive heading into the talks.

Iran and China's Position

One of the central flashpoints was how China — Iran's largest trading partner — intended to handle its relationship with Tehran. Trump reportedly delivered a pointed message to Xi, stating in strong terms that Chinese support for Iran was categorically unacceptable. The Chinese side responded by flatly denying that any such support was taking place.

Because the Strait of Hormuz is a critical chokepoint for global crude oil shipments, China's posture toward Iran will continue to have direct implications for energy markets, and the situation warrants close watching.

Trade War Truce Extended; Taiwan Remains a Stalemate

On the economic front, the two sides found some common ground. Treasury Secretary Bessent (ベッセント) confirmed in a Fox News interview that the two countries had agreed to extend the tariff truce in the ongoing trade war through January of next year. Negotiations toward a more comprehensive economic agreement will continue, but the temporary halt to the mutual tariff escalation provided at least short-term reassurance to markets.

On Taiwan, however, neither side moved from its established position. Talks on the issue were described as running in parallel without convergence.

Agreement to Call AI 'Superintelligence (SI)'

One of the more unexpected outcomes of the summit was a notable agreement on artificial intelligence. The two leaders announced that they had jointly agreed to refer to artificial intelligence as 'Superintelligence (SI).' Beyond nomenclature, they also agreed to establish a framework governing the risks and benefits of AI, with a follow-up meeting to be held by November. The agreement suggests that both major powers now share a recognition of rapidly advancing AI as a risk factor with potential implications for the survival of humanity.

The Thucydides Trap

A concept that drew particular attention was the 'Thucydides Trap,' which Xi invoked in his remarks during the summit. The term, coined by American international relations scholar Graham Allison, describes the tendency for violent conflict to erupt when a rising power threatens to displace an established hegemon.

Xi emphasized that the United States and China could overcome the Thucydides Trap, arguing that 'the great rejuvenation of the Chinese nation' and making America great again are not mutually exclusive goals — a clear signal of intent to avoid great-power conflict.

The summit ultimately reflected the inherent tension in the U.S.-China relationship: both sides repeatedly voiced a desire for stability, while simultaneously holding firm on lines they were unwilling to cross. Whether the two countries can genuinely escape the Thucydides Trap — and peacefully manage both the intensifying rivalry for global influence and the rapid evolution of AI — remains one of the defining questions of the years ahead.