US-China Military Standoff in the South China Sea

📡 THE SIGNAL — What Happened

Why it matters: In early 2026, military exercises by both the US and China in the South China Sea have overlapped in time and space, raising the risk of accidental clashes to post-Cold War highs. This tension is not merely a military contingency but the result of a structural spiral of conflict during a period of hegemonic transition.

• Military Trends — From January to March 2026, the US Navy conducted at least six "Freedom of Navigation Operations" (FONOPs) in the South China Sea, doubling the number from the same period last year.
• Military Trends — In February 2026, the People's Liberation Army Navy (PLAN) conducted its largest-ever live-fire exercise in the South China Sea, deploying the aircraft carrier "Fujian" to the area for the first time.
• Alliance Relations — In March, the US conducted "Balikatan Plus 2026," a quadrilateral joint maritime exercise with the Philippines, Japan, and Australia, with participating forces reaching a record high of 16,000 personnel.
• Territorial Claims — In January 2026, China constructed new anti-ship missile positions on Fiery Cross Reef in the Spratly Islands, effectively expanding its air defense identification zone.
• Diplomacy — A US-China defense ministers' meeting materialized at the Munich Security Conference in February 2026, but there was no concrete progress regarding a "Code of Conduct" for the South China Sea.
• Economy — International trade passing through the South China Sea amounts to approximately $5.3 trillion annually, accounting for about one-third of global maritime trade.
• Legal Framework — China continues to reject the 2016 international arbitral tribunal ruling (which denied China's nine-dash line claims), leading to an ongoing legal vacuum.
• Technology — The US deployed the new "Typhon" mid-range capability system, an anti-ship missile, to the northern Philippines, bringing mainland China within its range.
• Incidents — In January 2026, an incident occurred near Scarborough Shoal where a China Coast Guard vessel and a US Navy destroyer came within approximately 45 meters of each other.
• Energy — The South China Sea seabed is estimated to hold 11 billion barrels of oil and 190 trillion cubic feet of natural gas.
• Domestic Politics — Ahead of the 2026 US midterm elections, the Biden administration (or its successor) has extremely limited political room to soften its tough stance on China.
• ASEAN — ASEAN nations are experiencing deepening internal divisions as US-China tensions intensify, with Cambodia and Laos clearly aligning with China, and the Philippines and Vietnam aligning with the US.

To understand the US-China confrontation in the South China Sea, at least three historical contexts must be overlaid.

First, there is China's long-term narrative of the "Century of Humiliation" and the restoration of maritime rights and interests. For the Chinese Communist Party, claims over the South China Sea are not merely about resources or shipping lanes; they are central to the national narrative of overcoming the history of invasion and humiliation by Western powers since the Opium War of 1840 and achieving the great rejuvenation of the Chinese nation. While the historical basis for the nine-dash line is academically extremely weak, domestically it functions as a powerful source of legitimacy, and any leader retreating from this claim would be tantamount to political suicide.

Second, there is the lineage of the US's "Free and Open Indo-Pacific" strategy. Beginning with the Obama administration's "Asia Pivot" (2011), followed by the Trump administration's "Indo-Pacific Strategy" (2017), and the Biden administration's "Integrated Deterrence" (2021), the strategy towards China has been strengthened with each change in administration. Particularly after then-House Speaker Pelosi's visit to Taiwan in 2022, US-China relations entered a new structural phase. The South China Sea is also a critical operational area in the event of a Taiwan contingency, and for the US military, maintaining "freedom of navigation" here is a prerequisite for Taiwan's defense.

Third, there is the most fundamental context of structural changes in the international order. The structural tension between an existing hegemonic power and a rising challenger, which political scientist Graham Allison termed "Thucydides's Trap," is manifesting in the geographical focal point of the South China Sea. Allison's analysis that 12 out of 16 cases where a rising power challenged an existing hegemon in the past 500 years led to war casts an ominous shadow over current US-China relations.

What makes the situation in 2026 particularly dangerous is the simultaneous convergence of multiple factors. First, China's military modernization is approaching a critical point. The Chinese Navy surpasses the US Navy in ship numbers (approximately 370 vessels vs. approximately 290 vessels), and the local military balance in the South China Sea is increasingly tilting in China's favor. This could create a perception among China's leadership that "now is the window of opportunity for action."

Next, the reorganization of the US alliance network is accelerating. The alliance structure surrounding China is rapidly strengthening, including expanded military access to the Philippines based on the US-Philippines Mutual Defense Treaty (use of 9 bases through EDCA expansion), AUKUS (US-UK-Australia) submarine cooperation, and the institutionalization of US-Japan-Philippines trilateral cooperation. China views this as the construction of an "Asian NATO" and is intensifying its fear of encirclement.

Furthermore, both countries are in a domestically politically difficult situation for compromise. Xi Jinping has entered his third term, consolidating power, but incentives to play the nationalist card are strengthening amidst economic slowdown and the real estate crisis. On the US side, a bipartisan consensus for a tough stance on China has formed, and any president will seek to avoid being seen as "weak."

Historically, such a situation recalls Europe in 1914. At that time, too, the rigidification of alliances, an arms race, rising nationalism, and leaders' miscalculations that "the other side would back down" converged, leading to a world war that no one desired. In the South China Sea, although a direct military hotline exists between the US and China, it has often been interrupted since 2022, and institutional safeguards to prevent the escalation of accidental incidents are surprisingly fragile.

The core of the problem is that the status quo in the South China Sea is becoming unacceptable to both sides. China cannot tolerate challenges to its "core interests," and the US cannot abandon freedom of navigation, a core principle of the rules-based international order. This structural incompatibility is transforming routine military contacts into dangerous brinkmanship.

The delta: In early 2026, military activities by both the US and China simultaneously expanded rapidly, and institutional safeguards (hotlines, codes of conduct) designed to prevent accidental clashes have become dysfunctional. The qualitative difference from previous periods of tension lies in the convergence of shifts in the military balance (China's expanding local superiority) and political pressure (domestic politics on both sides), leading to the entrenchment of a "chicken game" structure.