[OPINION] Why a Chinese structure in Bajo de Masinloc is a sovereign red line

The National Task Force for the West Philippine Sea (NTF-WPS) recently confirmed what many security analysts had long feared: the People’s Republic of China (PRC) has installed an unauthorized floating structure inside the lagoon of Bajo de Masinloc (BdM), also known as Scarborough Shoal. 

Measuring roughly 7×7 meters, equipped with specialized antennas, and potentially anchored or stabilized by metal stilts, the platform coincided with an influx of Chinese research survey vessels lurking within the shoal. While the Philippine government immediately lodged strong diplomatic protests demanding its removal (and the Chinese embassy just announced the platform’s withdrawal on Wednesday, June 16), the episode serves as an alarming wake-up call. 

For the Philippines, the installation of any foreign hardware on Bajo de Masinloc is not a meaningless infraction or a temporary gray-zone maneuver. It represents an absolute, non-negotiable red line. Allowing even a single metallic stilt to anchor itself unchallenged within the shoal threatens to unhinge Philippine territorial integrity, rewrite regional history, and invite a repeat of past geopolitical tragedies.

China’s ‘creeping presence’ strategy

To understand why a seemingly modest 7×7 meter platform triggers such strong protests from Manila, one must look directly at China’s historical blueprint or playbook for South China Sea expansionism: the strategy of “creeping presence.” Beijing rarely takes strategic maritime features through overt, full-scale military invasions. Instead, it relies on incrementalism — salami-slicing tactics disguised as scientific research, civilian safety, or humanitarian shelter.

History provides a brutal, instructive lesson for the Philippines; one it has not forgotten. In 1995, the PRC erected crude, small wooden structures on Panganiban Reef (Mischief Reef). When confronted, Beijing claimed they were temporary shelters built to protect weary Chinese fishermen. Manila’s response at the time lacked the sustained pushback required to dislodge the intrusion. Fast forward to the present day: Panganiban Reef is a fully functioning, heavily fortified Chinese forward-operating base deep within the Philippine Exclusive Economic Zone (EEZ).

The exact same pretext of “scientific surveys” was deployed to occupy Kagitingan Reef (Fiery Cross Reef) and Zamora Reef (Subi Reef). Today, these three features form a highly strategic triangle of Chinese militarization in the South China Sea. Each hosts a massive 3,000-meter runway, advanced radar systems, hangars, deep-water naval piers, and sophisticated surface-to-air missile systems. They grant China the logistical and tactical capabilities to sustain illegal, coercive, aggressive, and deceptive  (ICAD) operations right on the Philippines’ doorstep, including harassments of Rotation and Resupply (RORE) missions to BRP Sierra Madre. 

And it looks like China is at it again. After the NTF WPS released photos and videos of the structure in BdM coupled with strong diplomatic pressure, the Chinese embassy in Manila finally admitted the presence of a structure but explained that it’s a “temporary scientific research facility” of the Chinese Academy of Sciences. It announced that the platform had been removed upon completion of the supposed research mission.

What’s worrying about this is that the “research structure” at Bajo de Masinloc seem to match the opening chapters of the Panganiban, Kagitingan, and Subi playbooks. It represents the preparatory groundwork — the hydrographic and architectural testing phase — required before embarking on permanent island reclamation. If the Philippines allows a single research platform to stand, it may implicitly be permitting the foundation of another Chinese forward-operating military base.

A Chinese base at BdM has huge implications for Philippine national security, far more serious than Panganiban Reef. A base there would effectively support a chokehold over the Luzon Strait and the maritime approaches to Manila and Subic. It would also increase Chinese surveillance of Philippine military bases and activities in Luzon. It is worth underscoring that the shoal is only 124 nautical miles from the coast of Zambales or 150 nautical miles from Metro Manila or Clark Air Base. It’s so near that a fighter jet based in BdM can reach Basa Air Base or Clark Air Base within 20 minutes.

A sovereignty rooted in law and history

China’s claims over Bajo de Masinloc are built on nebulous cartography. Historically, China ignored the shoal for centuries. It was only in 1947 that the Republic of China unilaterally sketched the infamous “9-dash line,” swallowing nearly the entire South China Sea within its domestic maps without historical or legal justification.

Conversely, the Philippine title over BdM is indisputable, continuous, and validated by centuries of international law. The shoal has been an organic part of the Philippine archipelago since time immemorial. The earliest colonial maps — most notably the iconic 1734 Murillo Velarde Map — clearly depict the feature under its native name, Panacot. When ownership of the Philippines shifted across colonial regimes, successive official American maps consistently drew BdM well inside the recognized territorial limits of the Philippine Islands.

If history was not enough, the international legal order definitively settled the matter on July 12, 2016. The Arbitral Tribunal constituted under the United Nations Convention on the Law of the Sea (UNCLOS) struck down China’s historical “9-dash line” claims, ruling them entirely devoid of legal basis. The tribunal reaffirmed that Bajo de Masinloc is a traditional fishing ground for Filipinos and falls squarely within areas where the Philippines holds exclusive sovereign rights and jurisdiction. Therefore, any structure placed into the lagoon without explicit authorization from Manila is a lawless intrusion. 

The imperative of the red line

By drawing an uncompromising red line at Bajo de Masinloc, the Philippine government sent an essential signal to both Beijing and the broader international community. The rapid deployment of formal diplomatic protests and the intensive aerial and maritime reconnaissance sweeps by the NTF-WPS, through the Philippine Air Force, Philippine Coast Guard (PCG) and the Bureau of Fisheries and Aquatic Resources (BFAR), demonstrate a vital shift in national posture. The Philippines is no longer willing to tolerate the gray-zone creeping that cost it precious maritime features in the 1990s. 

The removal of the platform proves that assertive diplomacy together with measured transparency is the right policy. When the Philippines calls out illegal structures and exposes them to global scrutiny, it raises the political and reputational costs for the aggressor state. However, the threat has not dissipated. The research vessels remain, and the appetite for expansion persists.

The Philippines, nonetheless, must remain unyielding. Bajo de Masinloc is a precious fishing ground for our fisherfolk, a strategic piece of real estate, and a sacred piece of national patrimony. Allowing foreign powers to establish permanent footholds through metal stilts and antennas would mean abdicating our constitutional duty to protect our maritime domain. History has taught us the cost of complacency. At Bajo de Masinloc, the line has been drawn in the water, and it must never be crossed. – Rappler.com

Dr. Jonathan Malaya is a former assistant director-general of the National Security Council and spokesperson of the NTF-WPS. He was also former undersecretary of the Department of the Interior and Local Government.