Assessing China’s Claim: UNCLOS and the South China Sea Dispute

Assessing China’s Claim: UNCLOS and the South China Sea Dispute

The People’s Republic’s increasingly assertive stance on maritime issues has brought it into serious conflict with several other states of the Pacific Rim. One of the most obstinate disputes is that with the Philippines on territories in the South China Sea. A closer look at the International Law of the Sea reveals that China has no legal basis to justify its claims.

1. The controversial Nine-dash Line

The United Nations Convention on the Law of the Sea (UNCLOS) was crafted to have a uniform standard in maritime delimitation. The travaux préparatoires show that the intent of the Convention was to avoid confusion and conflict with regard to the establishment of maritime boundaries. These efforts to clarify territorial authority notwithstanding, the People’s Republic of China, a signatory state to the UNCLOS, controversially maintains that the Nine-dash Line is their standard in claiming sovereignty over a huge expanse of the South China Sea.

2013-11-28 Ong Nine-dash line

The Nine-dash Line asserts sovereignty and sovereign rights over the 1.94 million km2 of the South China Sea, including its waters, seabed and all of the maritime features. The UNCLOS, however, provides no legal foundations to support this claim. Instead, China’s assertion is based on a historical claim by China that was once used by Taiwan. On this basis, China has built numerous artificial structures over rock formations, which under Article 121 of the UNCLOS fall short to be considered as islands that may create their own Exclusive Economic Zones (EEZ). Unless China can prove that these rock formations, which are submerged during low tide, can sustain human habitation or economic life; it cannot have its own EEZ in the South China Sea so as to support its assertion.

The same is true for claims referring to China’s continental shelf. Article 76, par. 1, of the UNCLOS provides that

the continental shelf of a coastal state comprises the seabed and subsoil of the submarine areas that extend beyond its territorial sea throughout the natural prolongation of its land territory to the outer edge of the continental margin, or to a distance of 200 nautical miles from the baselines from which the breadth of the territorial sea is measured where the outer edge of continental margin does not extend up to that distance.

The Nine-Dash line contravenes this provision because it includes a claim over Mischief Reef, which lies 600 miles from China’s Hainan island, but only 130 miles from the Philippine island province of Palawan. The breach of the UNCLOS by the Nine-Dash line claim is also apparent from China’s claim over the Scarborough and Spratly Islands.

2. Unfounded objections

China’s historical justifications run counter to its obligations under Art. 300 of the UNCLOS, which provides that states shall fulfil their obligations in good faith. Even if China raises the defense that it has never acknowledged certain provisions of the UNCLOS, the Continental Shelf doctrine as well as the EEZ doctrine have risen to the level of customary international law, as declared by the International Court of Justice (ICJ) in its decisions over the Libya/Malta North Continental Shelf Dispute and the Fisheries Jurisdiction Cases, and are therefore binding for China.

Moreover, China cannot raise that its domestic law, which provides its territorial boundaries, is inconsistent with the UNCLOS, as such objections are barred by Article 27 of the Vienna Convention on the Law of Treaties, which states that “a party may not invoke the provisions of its internal law as justification for its failure to perform.” Considering the pacta sunt servanda principle, China should fulfil its obligation under international law.

3. Legitimate claims by the Philippines

By contrast, the Philippines has legitimate historical grounds to claim parts of the West Philippine Sea. First, there was no protest in the course of or subsequent to the ratification of the Treaty of Paris in 1898 with respect to the exercise of sovereignty by the United States over all the land and sea territory embraced in that Treaty. This spans a period of almost half a century. In 1946, when the United States granted independence to the Philippines, which duly exercised sovereignty and jurisdiction over the same territory, neither was there any protest. Not until 1947 did the People’s Republic – and similarly, Taiwan – begin to claim rights over the Paracel and Spratly Islands by issuing maps that showed the islands as falling under their territory.

The Philippine claim over its entire maritime and territorial domain arising from the colonial treaties has been open and public as well as continuous and peaceful, and was exercised for a considerable length of time without protest from other states. Similar to the Netherlands in the Island of Palmas case against the United States in 1928, thus, the Philippines can raise the argument of prescription against any claims challenging its sovereignty. In the interest of promoting peace and order, the title is acquired and cannot be denied irrespective of whether the original taking of possession – in this case, by the Spanish colonial rulers – was unlawful in terms of the UNCLOS and whether there were subsequent protests thereto (quieta non movere).

Like China, the Philippines had initially reserved certain provisions of the UNCLOS so as not to prejudice the domestic laws providing the territorial extents of the country. However, these moves have been frowned upon by numerous states, like Australia, Hungary, Austria etc., who argue that such reservations are invalid as they negate the very intent of the convention. After all, international treaties are created to avoid resorting to non-binding references such as the history of a particular country. This prompted the Philippines to adjust its domestic laws and enacted RA 9552, or the Philippine Baseline Law, amending RA 3046 to harmonize it with UNCLOS.

If China’s historical claims were to be sustained, it would not only be incongruous with the UNCLOS but also a clear double standard against the preceding territorial claim of the Philippines.

Cesar Ruperto P. Ong is a student of San Beda College of Law, Manila, and a member of the San Beda International Law Society.

Image Source:

U.S. Central Intelligence Agency (1988): File:9 dotted line.png (, accessed 30.11.2013).