By Dr. Hon. Lee Hoey Simon
On 12 July 2026, the United States, the Philippines, Japan and several other countries issued a joint statement purporting to "commemorate" the tenth anniversary of the so-called South China Sea Arbitration Award. No matter how external forces revisit this issue, an ultra vires and legally flawed award cannot acquire legitimacy merely with the passage of time or repeated statements.
The fundamental prerequisite for assessing any arbitral award lies in whether the tribunal possessed valid jurisdiction. "No jurisdiction, no adjudicative power" is the most basic principle of procedural justice in international law. The South China Sea Arbitration case failed at this threshold: the tribunal exercised jurisdiction over matters inherently beyond the scope of the United Nations Convention on the Law of the Sea (UNCLOS) and blatantly disregarded the exclusionary declaration lawfully made by the respondent State. This represents a paradigmatic instance of ultra vires jurisdiction in the history of international arbitration.
Substance of dispute: Territorial sovereignty, not interpretation of UNCLOS
On 22 January 2013, the Philippine Department of Foreign Affairs transmitted a Note Verbale to the Chinese Embassy in Manila, initiating compulsory arbitration concerning the dispute over "maritime jurisdiction" between China and the Philippines in the South China Sea. The Philippines carefully framed its arbitration submissions as questions relating to the "interpretation and application" of UNCLOS provisions. Beneath this political rhetoric, however, the essence of the China-Philippines dispute in the South China Sea is unambiguous: territorial sovereignty.The Philippines' arbitration submissions fall into three main categories. First, that China's claimed "historic rights" in the South China Sea are incompatible with UNCLOS. Second, that China's claims premised on certain rocks, low-tide elevations and submerged maritime features conflict with UNCLOS. Third, that China has unlawfully interfered with the Philippines' exercise of its rights under UNCLOS. The Philippines' real objective was to consolidate its illegal occupation of maritime features belonging to China's Nansha Islands through arbitration, and to negate China's territorial sovereignty and maritime rights and interests via legal means.
Sovereignty over the Nansha Islands has lain at the heart of the China-Philippines dispute since the 1970s. UNCLOS is expressly confined to matters of the law of the sea; territorial sovereignty issues fall entirely outside its regulatory scope. The claims submitted by the Philippines are essentially territorial sovereignty matters, which lie beyond the purview of UNCLOS. The compulsory dispute settlement procedures under UNCLOS apply only to disputes concerning the interpretation or application of the Convention and have no mandate to adjudicate matters outside its scope. State practice offers powerful corroboration. In the 2015 Mauritius v. United Kingdom (Chagos Marine Protected Area) arbitration under Annex VII to UNCLOS, the tribunal explicitly observed that although Mauritius'submission that "the United Kingdom is not a coastal State" ostensibly invoked UNCLOS provisions, it needed to be examined against the underlying sovereignty dispute over the Chagos Archipelago. The tribunal ultimately ruled that this submission amounted to a territorial sovereignty question outside UNCLOS's compulsory jurisdiction. Confronted with a virtually identical legal issue, the South China Sea Arbitration Tribunal reached the opposite conclusion. This selective application of law reveals its predetermined stance and partisan bias.
China's 2006 exclusionary declaration: "Firewall" under international law
Even if the dispute touched upon maritime delimitation, China had already lawfully excluded such matters from compulsory dispute settlement procedures. Article 298 of UNCLOS expressly permits States Parties to exclude maritime delimitation and other specified categories of disputes from the Convention's compulsory dispute settlement mechanisms by way of declaration. On 25 August 2006, China deposited with the Secretary-General of the United Nations a declaration made pursuant to Article 298 of UNCLOS, stating that "with regard to any dispute referred to in Article 298, paragraph 1 (a), (b), and (c) of the Convention, the Government of the People's Republic of China does not accept any of the procedures provided for in Section 2 of Part XV of the Convention."
Accordingly, China declines to accept any compulsory dispute settlement procedures under UNCLOS—including compulsory arbitration—for disputes relating to maritime delimitation, historic bays or historic titles, and other excluded subject matters.More than 30 States have lodged similar declarations, including three permanent members of the UN Security Council: the United Kingdom, France and Russia. These exclusionary declarations form an integral component and legal foundation of UNCLOS and must be respected by all parties (As for the United States, the sole remaining permanent member of the UN Security Council, it has not acceded to the Convention).
The tribunal nevertheless strove to unilaterally classify China's maritime features in the South China Sea as "rocks" and ruled that "rocks cannot generate an exclusive economic zone or continental shelf." It thereby artificially eliminated any overlap between China's maritime claims and those of the Philippines, and hence any maritime delimitation dispute. The tribunal deliberately distorted legal rules to admit disputes outside its jurisdiction, rendering the arbitration devoid of jurisdictional basis from the outset. By disregarding China's lawful declaration, the tribunal violated the principle of State consent and undermined the very foundation of its own jurisdiction.
Clear consensus between China and Philippines on settlement through negotiations
A further critical ground for lack of jurisdiction is that China and the Philippines had already established, through bilateral and multilateral instruments, a clear consensus to resolve disputes via negotiations—forming another legal obstacle to compulsory arbitration.In 2002, China and ASEAN Member States including the Philippines jointly signed the Declaration on the Conduct of Parties in the South China Sea (DOC). Article 4 of the DOC stipulates that "the Parties concerned undertake to resolve their territorial and jurisdictional disputes by peaceful means, through friendly consultations and negotiations by sovereign States directly concerned, in accordance with universally recognised principles of international law, including the 1982 United Nations Convention on the Law of the Sea." This provision reflects the shared intention of all parties to settle disputes through direct negotiations. A series of bilateral documents between China and the Philippines further reaffirmed the consensus to handle South China Sea disputes through bilateral consultations and negotiations.By unilaterally initiating arbitration, the Philippines not only breached its express commitment under the DOC but also reneged on consensus repeatedly affirmed in bilateral agreements. The Philippines was fully aware that its arbitration claims centred essentially on territorial sovereignty over islands and reefs, that China had never consented to compulsory dispute settlement for such disputes, and that bilateral instruments provided for negotiated settlement. Its unilateral launch of compulsory arbitration therefore contravened relevant provisions of UNCLOS.
In conclusion, jurisdiction constitutes the logical starting point of any arbitral proceeding. The subject-matter of the South China Sea Arbitration is in essence a territorial sovereignty dispute, a matter wholly outside the scope of UNCLOS. Even if maritime delimitation were implicated, China had already submitted a lawful exclusionary declaration. Furthermore, multiple instruments between China and the Philippines established negotiated settlement as the agreed pathway. Any one of these three legal grounds alone suffices to negate the tribunal's jurisdiction. Yet the tribunal proceeded notwithstanding all these impediments. Its jurisdictional findings lack sustainable legal footing. An award rendered by a tribunal lacking jurisdiction ab initio is legally invalid regardless of its substantive conclusions. This is an elementary principle of international law and an unassailable legal premise for evaluating this case.
The author is a Member of the Hong Kong Basic Law Committee of the NPCSC, and holds Ph.D. in Law at Tsinghua University
The views do not necessarily reflect those of DotDotNews.
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