By Dr. Benjamin Blandin
The Trump administration is sharpening its Indo-Pacific strategy around a blunt military proposition: China must be convinced that any attempt to overturn the regional balance of power by force would fail.
During his first official visit to Southeast Asia as US Under Secretary of War for Policy, Elbridge Colby put the First Island Chain at the center of that strategy. Speaking at the Stratbase Institute in Manila last month, Colby described the Indo-Pacific as being of “paramount importance” and reaffirmed Washington’s determination to preserve a favorable balance of power. That means rebuilding a deterrence-by-denial posture capable of making aggression infeasible, escalation unattractive and war irrational.
Colby combined this reassurance with a demand for greater burden-sharing. Washington, he emphasized, sought “partners, not protectorates.” He praised the Philippines as a “model ally” for modernizing its armed forces and coast guard, and announced the rotational deployment of four US Fast Response Cutters to operate with the Philippine Coast Guard. His concluding formula—“strong and clear but quiet”—summarized an approach combining military strength with diplomatic restraint.
Yet Colby never explicitly mentioned China or the South China Sea. Nevertheless, both were present throughout his argument. From Manila, it was not difficult to identify the potential hegemon whose regional domination must be prevented, the aggression that denial must render infeasible, or the coercion that cannot be deterred by a signed piece of paper. The central question is therefore whether an architecture primarily designed to defeat conventional military aggression can also deter the forms of pressure that the Philippines confronts most frequently.
Since 2021, the Philippines has become the principal focal point of Chinese maritime coercion in the South China Sea. The author’s database records 168 Chinese-initiated naval and air incidents targeting the Philippines between 2021 and 2026—77 per cent of the 218 such incidents documented over the entire 1949–2026 period. This sharp increase has been accompanied by a diversification of the means employed, from maritime militia concentrations and dangerous maneuvers to water cannons, collisions and direct physical violence.
Confrontations increased further after Ferdinand Marcos Jr. took office in 2022. The strengthening of the US-Philippine alliance, expansion of Philippine patrols and adoption of assertive transparency coincided with more frequent and intense incidents. At Second Thomas Shoal, Chinese obstruction of missions to the BRP Sierra Madre progressed from blocking and dangerous maneuvers to lasers, water cannons, collisions and physical violence. On June 17, 2024, Chinese personnel boarded Philippine boats, destroyed equipment, and used knives, axes, and other implements. Several Filipino personnel were injured, including a sailor who lost a thumb. The episode approached the threshold of an armed attack while remaining ambiguous enough to complicate a military response.
Chinese pressure also spread to other locations and took more diverse forms. Around Scarborough Shoal, China combined persistent patrols with barriers, water cannons and interference with Filipino fishermen and government vessels. At Sabina Shoal, it relied on sustained deployments and close-quarter coercion. In 2025, Chinese forces obstructed scientific activities near Sandy Cay, raised the Chinese flag there and repeatedly confronted Philippine vessels around Scarborough. During one high-speed interception, a Chinese coast guard ship collided with a PLA Navy destroyer while pursuing a Philippine patrol vessel. Chinese naval and air patrols in 2026 further demonstrated how coast guard coercion can be backed by military power.
The underlying approach is not new. China used force to seize the Paracels in 1974 and several Spratly features in 1988. It later achieved changes at lower cost by establishing supposedly civilian “fishermen shelters” on Mischief Reef in 1994 and gaining effective control of Scarborough Shoal in 2012 without a naval battle. Beijing has since consolidated its position through persistence, ambiguity and the normalization of Chinese control.
These actions form part of a broader system of Chinese asymmetric warfare along the First Island Chain. Beijing combines area denial, supported by the PLA and its fortified-island network; hybrid warfare, involving civilian, paramilitary, legal, informational, economic and scientific instruments; and grey-zone tactics designed to alter the status quo without provoking open conflict. The China Coast Guard and maritime militia operate in the foreground, supported by research vessels, buoys, unmanned systems and other dual-use platforms. The Chinese navy remains in the background, providing support while retaining the ability to intervene if the confrontation escalates.
This model also compensates for genuine constraints. The PLA Navy is divided among several bodies of water and missions, only part is continuously available, and coordination remains complex. A major conflict would expose these limitations. Asymmetric warfare instead allows Beijing to mobilize numbers, persistence and ambiguity while forcing opponents to choose between acquiescence and a disproportionate response. China’s apparent restraint is a means of pursuing its ambitions at lower risk.
This creates a gap in the existing deterrence architecture. US and Philippine investments in missiles, bases, logistics and military readiness can raise the cost of a major attack. They do not automatically prevent a coast guard vessel from blocking a resupply mission, a maritime militia swarm from occupying waters for months, or dual-use platforms from collecting information and damaging critical infrastructure. Indeed, the stronger conventional deterrence becomes, the greater Beijing’s incentive may be to remain below its threshold and pursue incremental gains against which military retaliation would appear excessive.
Colby’s strategy should therefore be extended to these lower levels of confrontation. In the West Philippine Sea, deterrence by denial must mean preventing China from achieving limited objectives through sub-threshold coercion, not merely denying it victory in a major war. This requires more vessels at sea, stronger maritime domain awareness, resilient communications and outposts, diversified resupply systems, and regulated non-lethal capabilities allowing Philippine personnel to repel hostile actions without becoming the first to use lethal force. The US cutters are particularly relevant because they connect the alliance’s military posture with the law-enforcement environment in which coercion occurs.
Credible deterrence ultimately depends on capabilities and political will. Its success, however, cannot be measured solely by whether the alliance could defeat overt aggression. It must also be assessed by whether Filipino fishermen can operate, Philippine vessels can resupply their positions, and Manila can exercise its lawful rights without being progressively excluded from its waters. Deterrence by denial will only be credible if it addresses the full spectrum of Chinese asymmetric warfare—from a missile attack to a water cannon, a maritime militia swarm or the incremental seizure of another feature.
Dr. Benjamin Blandin is a French geopolitics scholar specializing in China’s asymmetric warfare along the First Island Chain, including unmanned, hybrid and unconventional naval capabilities. He is a visiting research fellow at Taiwan’s Institute for National Defense and Security Research and previously worked in strategy and innovation at Airbus Defence and Space.
