Risky expansion of US coalition's military footprint in South China Sea

A report released this week in Beijing by the South China Sea Strategic Situation Probing Initiative paints a revealing picture of US military activities in the South China Sea during 2025.

Four carrier strike groups entered the South China Sea nine times. Eleven attack submarines and one guided-missile submarine operated in surrounding waters. Around 1,200 close-in reconnaissance flights were conducted, while more than 120 major military exercises unfolded across the Western Pacific.

And these activities on China's doorstep continued with remarkable frequency despite US armed forces being stretched across the Caribbean, the Middle East and other theaters.

US operations in the Western Pacific increasingly resemble an institution running on autopilot. As political attention in Washington shifts elsewhere, operational decisions fall on commanders whose incentives naturally favor maintaining or expanding established patterns of deployment.

Under this dynamic, there are growing signs of increasingly assertive and provocative maneuvers, which could complicate the relatively restrained military-to-military interactions between China and the US seen since late 2023.

Technology further complicates the equation.

Facing finite manpower and overstretched assets, the US military has expanded its reliance on unmanned systems. Large reconnaissance drones such as the MQ-4C Triton and MQ-9 Reaper now account for roughly 30 percent of US close-in aerial reconnaissance directed at China, according to the report. Drones lower the threshold for increasingly frequent surveillance missions precisely because they carry fewer immediate political consequences, thereby increasing operational-level risks.

That tendency sits uneasily with the broader diplomatic objective that both Beijing and Washington have pursued in recent years: preserving strategic stability despite differences.

History suggests that new technologies rarely remove strategic risk; they merely relocate it. Greater automation can encourage greater operational boldness while leaving escalation dynamics largely unchanged.

The increasingly confrontational nature of allied military exercises reinforces this concern. Recent drills have moved well beyond traditional interoperability training. They increasingly emphasize artificial intelligence, long-range precision strikes, cyber operations and autonomous systems. Exercises such as Talisman Sabre 2025, a bilateral combined training activity between Australia and the US, involving 19 nations and multi-domain warfighting, introduced AI-assisted operational decision-making, while the Balikatan 2025 large-scale rills between the US and the Philippines, as well as observers from 16 other countries, deployed advanced missile systems in the Philippines for the first time.

Against this backdrop, the ongoing RIMPAC 2026 exercise carries significance beyond its impressive scale of 31 participating countries, 40 warships, five submarines, over 200 aircraft and 30,000 personnel. Its operational scenarios, integrated command structures and emphasis on anti-submarine warfare, amphibious operations and coalition interoperability suggest contingency planning for a conflict with China.

Equally telling is the political messaging. Many participating officials openly frame the exercise around deterring so-called "authoritarian expansion” and strengthening the defense of first and second island chains in the Asia-Pacific.

The result is an increasingly familiar pattern: one side expands the integration of coalition forces, the other strengthens anti-access capabilities.

This is the central contradiction confronting the region. As for the US and its allies, every exercise is described as defensive and every deployment is justified as deterrence. Yet collectively they create an environment where the signal of aggressive posturing far outweighs reassurances.

The South China Sea does not suffer from a shortage of military hardware. When routines become detached from strategic purpose, deterrence risks becoming an end in itself rather than a means to preserve peace. That is a lesson Washington and its regional partners would do well to remember.