Read Part I of this blog post here.

I explained that in its 1975 and 1979 legal interpretations of the Mutual Defense Treaty (MDT) with the Philippines, U.S. denied any legal obligation to defend the Philippines in an armed conflict over the Spratly Islands. These legal interpretations were not revised in the 2024 statements of the U.S. government for the U.S. is even careful to limit its commitment in the SCS to situations of “armed attack” against Philippine “armed forces, public vessels, aircraft-including those of its coast guard” but not Spratly Islands being claimed or occupied by the Philippines.

The question is whether U.S. commitment was deemed expanded by reason of the SCS Arbitration.

2017 U.S. Legal Position on the SCS Arbitral Award

Following the issuance of the SCS Arbitral Award, Taiwan deployed a naval armada “to patrol the South China Sea”. Being non-parties to the SCS arbitration, Vietnam and Malaysia are not bound by it but have been selective in their support of the Arbitral Award. For instance, Vietnam supports the Arbitral Award’s ruling that  China’s nine-dash line is contrary to the convention. Yet, in its 2023 administrative map, Vietnam maintained its claim to the Spratly Islands as an archipelago or Troung Sa, thereby defying the ruling that no littoral state may claim an archipelago in the SCS.

The U.S. interpreted the Arbitral Award to mean that China “cannot lawfully assert a maritime claim … vis-a-vis the Philippines in areas that the Tribunal found to be in the Philippines’ EEZ or on its continental shelf.” China “has no lawful territorial or maritime claim to Mischief Reef or Second Thomas Shoal, both of which fall fully under the Philippines’ sovereign rights and jurisdiction, nor does Beijing have any territorial or maritime claims generated from these features.”

 It should be borne in mind that the Philippine EEZ and Continental Shelf (CS) is interrupted by numerous rocks with pockets of territorial sea. The SCS Arbitral Tribunal recognized that there are rocks within 200 nautical miles from the Philippines coasts that are occupied by China, Taiwan, Vietnam, and Malaysia and that each rock, including Itu Aba occupied by Taiwan, has a 12-nautical mile territorial sea. As the Arbitral Tribunal had no jurisdiction to resolve the territorial status of these pockets of territorial sea vis-à-vis the maritime entitlement of the Philippines, it  merely declared that the Philippine EEZ and CS is “beyond 12 M from any high-tide feature within the South China Sea.” This definition of the Philippine EEZ and CS further confines the scope of application of the MDT.

Thus, an armed attack by China against the Philippines would engage the U.S. commitment under the MDT if directed at Philippine armed forces, public vessels, and aircraft, including coastguard vessels, while the latter are within the Philippine EEZ but not when they are on the disputed Spratly Islands or their respective territorial seas. However, the question remains whether a similar armed attack by Taiwan, Vietnam, or Malaysia would also engage U.S. commitment. Through their new coast guard laws, China, Taiwan and Vietnam authorize use of lethal force against perceived threats to their territorial and maritime claims in the SCS.

The Second Thomas Shoal where the Philippine Navy’s 80-year-old BRP Sierra Madre has been intentionally beached is a low tide elevation found in the Philippines EEZ. Nevertheless, BRP Sierra Madre, though derelict, is a Philippine naval vessel and the troops stationed therein are covered by the MDT. Philippine coastguard vessels and personnel on rotation and resupply missions in Second Thomas Shoal have been harassed and attacked by China by means of vessel-ramming and firing of laser beams and water cannons. These drew U.S. condemnation but not military force in defense of the Philippines.

Near Reed Bank, the Philippines converted decommissioned oil and gas platforms into naval outposts. Philippine forces and vessels in these installations would come within the coverage of the MDT, especially as Reed Bank is recognized by the U.S. as part of Philippine CS.

Another hotspot between the Philippines and China is Scarborough Shoal. China presently controls access to this shoal. The Arbitral Award recognized that fishing in the territorial waters of the shoal is a right common to Filipino, Chinese and Vietnamese fishermen. Consequently, any fishing dispute between the Philippines and China in the shoal would be territorial in nature. The 1975 U.S. legal interpretation excludes such dispute from the scope of American obligation to defend the Philippines. The U.S. interpretation of the Arbitral Award did not revise this legal interpretation of the MDT.

A Nothing-Burger

As if by design, the Kissinger memo-followed by the Vance letter and current U.S. pronouncements-had created a fine ambiguity concerning the scope of obligations under the MDT. This ambiguity is one liable to enthusiastic (mis)interpretations by Filipino leaders, much to American advantage and quite possibly, to deep Filipino sorrows.

American obligation to defend the Philippines in the South China Sea is a nothing-burger. The question for Filipinos is whether they would risk upgrading this obligation under a renegotiated MDT given the certainty of a conflict between U.S. and China for dominance in the region. The question for Americans is whether they would be willing to foot the bill with their lives on tiny rocks thousands of miles across the Pacific.

Melissa Loja is a Postdoctoral Fellow at University of Copenhagen. She is the author of “International Agreements between Non-state Actors as a Source of International Law” (Hart, 2022) and various journal articles in the European Journal of International Law, the International Journal of Constitutional Law and the Leiden Journal of International Law.

Romel Regalado Bagares is a professorial lecturer in international law in three Manila-based law schools and the Philippine Judicial Academy. His latest publication (with José Duke Bagulaya), ‘Hidden in Plain Sight: International Law and Marxist Praxis in the Life and Works of Merlin M. Magallona’ was published in the Asian Journal of International Law.

Read more on Asian law topics in the Asian Journal of International Law.