Ill-advised?

Without a doubt, the Philippine-Indonesian common exclusive economic zone (EEZ) boundary agreement—mentioned by President Marcos Jr. in his Indonesian state visit as a “template” for talks with China over the South China Sea (SCS)—is monumental.

Signed between the two countries in 2014 and taking effect in 2019, it put to rest an 86-year-old dispute dating back to the age of colonization.

Yet, its history may offer Mr. Marcos key lessons.

In 1928, Swiss arbitrator Max Huber awarded to the Netherlands, Indonesia’s colonizer, Miangas, a tiny island around 50 miles off Cape San Agustin in Davao. In the procedure they had initiated, the Americans claimed ownership of the island on the basis of the 1898 Treaty of Paris (TOP).

Under the TOP, the Spaniards ceded the Philippines to the former for $20 million. That included Miangas—claimed by Spaniards on the basis of the doctrine of discovery as their “Palmas”—an island lying well within the TOP’s so-called International Treaty Limits (ITL). This the Americans illustrated in a 1902 map annexed as Exhibit 11 of their memorandum to the Palmas arbitration.

But Huber famously held that “effective occupation” must follow discovery, for title to the territory to become unassailable. Thus, Miangas went to the Dutch, although it lies within the ITL and is nearer to the Philippines than it is to what is now Indonesia in the Sulu-Sulawesi Sea (SSS).

Filipinos took to heart the lessons of Palmas. From the 1935 to the 1987 Constitutions, we defined national territory according to the TOP’s 1902 map, treating its rectangular-shaped lines as territorial and refusing to recognize Huber’s Miangas award.

In 1994, when Indonesia and the Philippines opened talks for a common EEZ boundary in the SSS, we asserted the TOP regime over the UN Convention on the Law of the Sea (Unclos) invoked by Indonesia, although both are parties to the Law of the Sea.

However, in 2009, the Philippines passed Republic Act No. 9522, a new Unclos-compliant baselines law. In 2011, in Magallona v. Executive Secretary, the Supreme Court upheld the law’s constitutionality. Then, in 2013, the Philippines sued China before the Unclos Arbitral Tribunal over the latter’s expansive nine-dash line claim.

In 2014, after 20 years of negotiations, the Philippines agreed to sign the common EEZ boundary treaty with Indonesia, foreswearing the TOP in favor of Unclos rules. Indonesian Ambassador Arif Havas Oegroseno prophetically declared that the agreement “signifies the emergence of a state practice whereby in a maritime boundary dispute a unilateral proclamation of maps will eventually be aligned with prevailing international law.”

The 2014 agreement is of a piece with RA 9522 and the Magallona case; without these, the Philippines could not have had come to Arbitral Court with clean hands to question China’s nine-dash line claim. Had the Philippines stuck to the TOP, the Arbitral Court would have been ousted of jurisdiction, as it is a territorial claim tacking the Kalayaan Island Group to one of its legs.

In 2016, the Arbitral Award, noting that the Philippines has abandoned the TOP (para. 223), invalidated China’s nine-dash line as a historic rights claim exceeding its maritime entitlements under the Unclos (para. 261). Consequently, it also held that as to any disputed feature in the SCS, there is at all no overlap between the Philippine and Chinese EEZs (para. 683).

Thus, if Mr. Marcos, in his Indonesian statement, simply meant that like the Philippine-Indonesian common EEZ boundary, Philippines-Chinese SCS discussions ought to be governed by Unclos, well and good.

But if he meant that there is in fact an overlap in the EEZs of the two countries, then he is being ill-advised. For that meant no less than our abandonment of the 2016 Arbitral Award.

Melissa Loja and Romel Bagares are independent Filipino scholars of international law.