On Monday, at the 13th ASEAN-US Summit hosted by Malaysian Prime Minister Anwar Ibrahim and US President Donald Trump in Kuala Lumpur, President Ferdinand R. Marcos called the attention of the world leaders — including Chinese Premier Li Qiang — to the “continued incidents in the South China Sea that endanger the lives of Philippine military personnel and compromise the safety of vessels and aircraft.”

He didn’t particularly name China — he didn’t need to — when he denounced moves to make Bajo de Masinloc (Scarborough Shoal) a “nature reserve,” a clear violation of Philippine sovereignty and international law based on the 1982 United Nations Convention on the Law of the Sea (UNCLOS) and the 2016 Permanent Court of Arbitration (PCA) ruling that invalidated China’s nine-dash-line claim to resources in the South China Sea.

This even as President Marcos categorically expressed the Philippines’ “strong protest” to China’s declaration of a “national nature reserve” at Scarborough Shoal.

To recall, the PCA ruling confirmed the Philippines’ sovereign rights within its 200-nautical mile exclusive economic zone under UNCLOS and declared the award legally binding on the parties concerned.

“Bajo de Masinloc is a longstanding and integral part of the Philippines over which it has sovereignty and jurisdiction,” Marcos stressed in Kuala Lumpur as the Asean leaders, including the Chinese premier, sat in rapt attention.

China had announced last September its plan to establish a nature reserve in a designated site at Scarborough Shoal. The shoal had suffered from destructive Chinese clam harvesting.

Satellite imagery in 2023 of the Center for Strategic International Studies’ Asia Maritime Transparency Initiative measured over 16,000 acres of clam harvesting damage across 39 shallow reefs in the South China Sea. The damage to Scarborough Shoal covered some 1,900 acres.

Basically, the damage was caused by a particular clam harvesting technique practiced by Chinese fishermen to access giant clam shells buried in the reef for which there is a lucrative jewelry and statuary market in China.

The clam harvesting at Scarborough took place under the watchful eyes of the China Coast Guard, which has maintained a permanent presence at Scarborough Shoal since China seized control of it from the Philippines in 2012.

The nature reserve that China wants to establish builds upon its declaration of territorial baselines at Scarborough in 2024 in an effort to formalize its control over the disputed reef. This then would serve as the basis for Chinese restriction of Philippine fishermen from the area, another violation of the 2016 arbitral ruling that said China must respect Philippine traditional fishing rights at Scarborough.

The Philippines, backed by its strongest Western ally, the US, has already filed a formal diplomatic protest with China.

Meanwhile, the Chinese Foreign Ministry in Beijing insisted that it is within China’s sovereign rights to establish a natural reserve at Scarborough so as to protect the area’s ecological diversity and sustainability. China, said the ministry’s spokesperson, “does not accept the Philippines’ groundless accusations and so-called protests.”

The Philippines can’t force China to leave Scarborough Shoal through military means, but the country isn’t completely powerless. It can sustain and internationalize its diplomatic protest. It can meticulously document all encounters with Chinese maritime forces with evidence compiled into regular reports and shared not just with ASEAN but with the United Nations and international media. The goal is to make China’s incremental actions visible and costly to its international reputation.

The country’s greatest legal asset is still the 2016 Permanent Court of Arbitration ruling that states unequivocally that Scarborough Shoal is a traditional fishing ground of several nations, while declaring that China’s nine-dash-line claim in the SCS has absolutely no genuine legal basis.

The path forward for the Philippines necessitates strategic patience, unwavering principle, and the savvy to turn a bilateral dispute into a multilateral concern for rules-based international order.

Manila must continue to make the PCA ruling the cornerstone of the country’s foreign policy on the SCS; it must be mentioned in every speech of the President and the diplomatic corps; it must be included in every diplomatic note; and used to challenge China’s “sovereign rights” narrative at every turn.

And the perennial message to China should be made loud and clear: our position is based on international law, yours is based on raw power.