Our West Philippine Sea chop suey

The recent Senate brouhaha over the West Philippine Sea (WPS) shows all too clearly that the problem is not whether the 2016 Arbitral Award (AA) under the United Nations Convention on the Law of the Sea (Unclos) is binding. Without any doubt, it is. The problem lies in how the Philippines has come to describe the WPS, despite the AA.

In the Senate debate, several legal categories were folded into one. Sen. Francis Pangilinan and Sen. Panfilo Lacson treated the Kalayaan Island Group (KIG), the Philippine archipelagic exclusive economic zone (EEZ), and the WPS as interchangeable.

Per Pangilinan, the WPS is simply the EEZ, awarded to the Philippines by the AA, which also implicitly authorized its naming. Mapping, he suggested, was unnecessary because the 2009 Archipelagic Baselines Law already established the reference points for measuring the EEZ’s 370-kilometer extent. Lacson, citing Presidential Decree No. 1596, treated the KIG as an enclosed area allegedly affirmed by the Tribunal, then folded it into the EEZ and labeled the whole as the WPS.

Former Sen. Francis Tolentino claimed that a map of the WPS already exists, only to qualify later that it merely depicts archipelagic baselines and sea-lanes. Retired Senior Associate Justice Antonio Carpio and professor Jay Batongbacal emphasized that demarcation is not a prerequisite to Philippine maritime rights, effectively asserting EEZ and the KIG as a single undifferentiated space. They are correct in one sense. But we still have EEZ overlaps with Malaysia (Sabah area) and Taiwan (Bashi Channel and Pratas). We need to fix the exact coordinates of our EEZ’s outer margin, to determine the median line for establishing a common EEZ boundary for each overlap.

Sen. Rodante Marcoleta attempted to deconstruct this mix. Instead, he cooked up a mess of pottage.

Yet Marcoleta was correct on one crucial point. Several KIG features–including the largest high tide elevation (HTE) in the Spratlys, Pagasa–lie outside the EEZ and are separated from it and from each other—by areas of high seas (AA, paragraphs 199, 231, 269, 285-86, 288-89, 384). HTEs inside the EEZ (Bajo de Masinloc, for example) and those, like Pagasa, lie outside it, generate a territorial sea. Their territorial sea’s coordinates need to be laid down, to separate the HTEs from the surrounding EEZ or high seas, as the case may be. Once this is acknowledged, the question of demarcation cannot be dismissed so easily.

That question is too important to be left to politics. Several Philippine laws expressly apply to the WPS.

Republic Act No. 9522 deliberately excluded the KIG from the Philippines’ archipelagic baselines. The legal consequence is straightforward: the EEZ generated from the main Philippine archipelago does not extend to Pagasa Island and several other Philippine-occupied or claimed features in the KIG. These features lie outside the EEZ.

Nor is the KIG a compact or continuous maritime space. It is a scattered group of features, some of which are separated by waters classified by Unclos as high seas. The AA (paragraphs 574-575) made clear that no claimant state may construct an offshore archipelago in the Spratlys—the legal effect that PD 1596 had attempted to produce.

Pagasa is unquestionably part of the WPS. But it is separated from the EEZ by waters that are not Philippine maritime zones. Those intervening waters are high seas now subject in part to the new Agreement on the Conservation and Sustainable Use of Marine Biological Diversity of Areas Beyond National Jurisdiction, to which the Philippines became a party in September 2025.

The WPS is not a category derived from Unclos. Territorial seas, EEZs, continental shelves, and the high seas are. The WPS, well-meaning it may be, is a Philippine policy construct that overlays these distinct legal regimes.

Treating the WPS as a single, continuous space risks asserting claims into waters no state may claim as its own, and where other states enjoy freedoms of navigation and overflight as a matter of right. Imprecision inflames rhetoric and complicates diplomacy.

If the Philippines chooses to maintain a broad conception of the WPS, it owes the international community clarity. It must state plainly that the WPS includes not only EEZ entitlements and territorial seas, but also intervening areas of high seas connecting the KIG to the main archipelago. Anything less undermines the very legal victory the Philippines secured in 2016.

Marcoleta’s intervention failed because it lacked precision. Pangilinan’s defense faltered because it assumed continuity where the law of the sea demands careful differentiation. Chop suey is indeed a savory Filipino heritage. But as a legal method for defining maritime zones and jurisdiction in the South China Sea, it’s a perfect recipe for legal obfuscation the Philippines can only pursue at its own peril.

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Romel Regalado Bagares is a professorial lecturer in international law for the Philippine Judicial Academy.