US-China Confrontation in the South China Sea

📡 THE SIGNAL — What Happened

Why it matters: In early 2026, both the US and China have simultaneously intensified military exercises and patrol activities in the South China Sea, raising the risk of accidental military conflict to its highest level since the Cold War. The domestic politics of both nations have created a structure where "weakness" is not tolerated, making escalation control extremely difficult.

• Military Trends — From January to March 2026, the US Navy conducted "Freedom of Navigation" operations in the South China Sea at an unprecedented pace. Joint patrols with the Philippines, Japan, and Australia were expanded to more than twice a month.
• Military Trends — The Chinese People's Liberation Army Navy conducted a large-scale military exercise "Likian" (Sharp Sword) in the South China Sea in February 2026. A fleet including the aircraft carrier "Fujian" participated, conducting anti-ship ballistic missile launch drills.
• Territorial Claims — China continues to intimidate Philippine fishing vessels around the Spratly and Paracel Islands based on its revised "Ten-dash line" map from 2024. As of 2026, three clashes have been reported around Second Thomas Shoal.
• Alliance Relations — Based on the US-Philippines Mutual Defense Treaty, US military access to bases in the Philippines expanded to nine locations in 2025. Discussions are underway for an additional new base in southern Palawan in 2026.
• Diplomacy — Direct dialogue between US and Chinese leaders has ceased since the APEC Summit in November 2025. The military-to-military hotline has also been effectively non-functional since October 2025.
• Economy — The South China Sea is a vital maritime chokepoint through which approximately one-third of global trade passes, with goods worth approximately $5.3 trillion annually transiting its waters.
• Domestic Politics — In the US, with the November 2026 midterm elections approaching, both Republican and Democratic parties are competing to adopt a hardline stance against China, making a shift towards dialogue politically costly.
• Domestic Politics — In China, ahead of the 21st Party Congress in 2027, the Xi Jinping administration has virtually no room to compromise on its South China Sea territorial claims, which it views as a "core interest."
• Military Technology — China has completed radar facilities, anti-aircraft missiles, and runways on seven artificial islands in the Spratly Islands. The militarization has reached its final stage.
• International Law — China continues to reject the 2016 Permanent Court of Arbitration ruling (which invalidated China's Nine-dash line claims), undermining the foundation of the rules-based order.
• Resources — The South China Sea is estimated to hold 11 billion barrels of oil and 190 trillion cubic feet of natural gas.
• Armaments — The US increased the Indo-Pacific Command's budget by 12% year-on-year to approximately $9.2 billion in fiscal year 2026, significantly strengthening the Pacific Deterrence Initiative (PDI).

To understand the US-China confrontation in the South China Sea, it is necessary to survey at least half a century of geopolitical changes.

The South China Sea became a focal point of international politics dating back to the Cold War. In 1974, China (then the People's Republic of China) militarily occupied the Paracel Islands, which were under South Vietnamese control. This was China's first large-scale use of force in the South China Sea and became the prototype for its subsequent "salami-slicing" strategy. In 1988, the Vietnamese Navy and the Chinese Navy clashed at Johnson South Reef in the Spratly Islands, resulting in 64 Vietnamese deaths. During this period, the US was focused on its anti-Soviet strategy towards the end of the Cold War, and its involvement in the South China Sea was limited.

A turning point came in 1995 when China constructed structures on Mischief Reef, claimed by the Philippines, sending shockwaves through ASEAN nations. The US, which had been enjoying post-Cold War "unipolarity," re-recognized the strategic importance of the South China Sea and gradually began to strengthen its involvement in the region. However, as the 2001 Hainan Island incident (a collision between a US EP-3 reconnaissance aircraft and a Chinese fighter jet) showed, the risk of military contact between the US and China had been evident since the early 21st century.

Subsequently, China's rise accelerated. After the 2008 Lehman Shock, China became more confident in its economic and military growth and began to assert its claims in the South China Sea more aggressively. In 2012, the Philippine Navy and the China Coast Guard engaged in a two-month standoff at Scarborough Shoal, ultimately leading to China establishing effective control. This successful experience emboldened China's subsequent bold decision to construct artificial islands.

From 2013 to 2016, China extensively reclaimed seven reefs in the Spratly Islands, creating a total of approximately 1,300 hectares of artificial islands. Runways, radar facilities, and anti-aircraft/anti-ship missiles were deployed, fundamentally redrawing the military map of the South China Sea. The Obama administration countered with "Freedom of Navigation" operations but could not stop the construction of artificial islands. The 2016 Permanent Court of Arbitration ruling comprehensively rejected China's Nine-dash line claims, but China dismissed the ruling as "a piece of paper," posing a serious challenge to the international legal order.

During the first Trump administration (2017-2021), US-China rivalry intensified, primarily centered on trade wars, and the US Navy's presence in the South China Sea was strengthened. The Biden administration (2021-2025) focused on strengthening alliance networks, including the establishment of AUKUS (Australia-UK-US security pact) and the expansion of Enhanced Defense Cooperation Agreement (EDCA) sites with the Philippines. However, this strategy further provoked China, accelerating its military buildup in response to what it perceived as "encirclement."

Since 2025, the situation has become even more tense. As the Marcos Jr. administration in the Philippines maintained its resupply missions to Second Thomas Shoal, physical clashes with the China Coast Guard frequently occurred. In mid-2025, multiple incidents resulted in injuries to Philippine military personnel, bringing the application of the US-Philippines Mutual Defense Treaty onto the table for realistic discussion.

And now in 2026, the structural spiral of conflict is accelerating. The US cannot ease its hardline stance against China ahead of the midterm elections, and China maintains its position of defending "core interests" in preparation for the 2027 Party Congress. The domestic politics of both sides are stripping away diplomatic flexibility, structurally increasing the risk that accidental clashes could escalate into planned escalation. History teaches that great power rivalries become most dangerous when both sides are pushed into a situation where they "cannot back down." The Sarajevo incident in 1914 escalated into World War I precisely because great power alliance obligations and domestic politics made "rational retreat" impossible.

The delta: The biggest change is that the domestic politics of both the US and China are structurally making "escalation management" difficult. With the 2026 midterm elections in the US and the 2027 Party Congress in China, showing "weakness" externally has become political suicide for both. Furthermore, the de facto suspension of the military hotline has dramatically increased the danger of accidental incidents rapidly escalating. The communication breakdown at the operational commander level between the two militaries is the most dangerous new variable.