Foreign Relations & International Law

Limits in the Seas No. 150 and the U.S.’s Misinterpretation of ‘Historic Rights’

Sourabh Gupta
Tuesday, July 26, 2022, 8:01 AM

Past and present law of the sea jurisprudence suggests that the State Department’s most recent analysis of South China Sea entitlements is legally flawed.

USS Carl Vinson transits the South China Sea (Official US Navy Page,; CC BY 2.0,

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In 2013, the Phillipines brought a case against China concerning maritime rights in the South China Sea. It did so under Annex VII of the U.N. Convention on the Law of the Sea (UNCLOS), which establishes a special arbitral tribunal to resolve disputes concerning international agreements between member states. The tribunal issued its decision in Philippines v. China three years later, in July 2016—a landmark ruling that shot down China’s claim to “historic rights”over maritime areas of the South China Sea encompassed by the “nine-dash line.”

Today, the South China Sea Arbitration Award highlights a fallacy in the U.S.’s own analysis of maritime rights.

The tribunal judged China’s “historic rights” claim to be an exclusive one to the living and nonliving resources of the relevant portion of the Philippines’ exclusive economic zone (EEZ). This meant that China had sought to exercise an indivisible sovereign right to explore, exploit, conserve, and manage the natural resources of the sea in an area that rightfully fell within the jurisdiction of the Philippines. Since there cannot be two equally definitive exclusive rights claims to a single water body, the tribunal was quite obviously correct to judge that Beijing’s claim exceeded the geographic and substantive limits of its entitlements under the convention. 

At first, it was not entirely clear whether the tribunal was correct to designate China’s “historic rights” claim as an exclusive one. None of the four instances of proof furnished by Manila at the time showed China actually exercising these (exclusive) rights in a nonconforming sea area. But in the years since, the correctness of the tribunal’s ruling has only been reconfirmed, with Beijing interfering on multiple occasions with Hanoi’s, Jakarta’s, and Kuala Lumpur’s exclusive rights to develop oil and gas resources in their respective sectors of the South China Sea. (China might quibble that it was not defending a “historic right;” rather, it was enforcing Article 5 of the November 2002 Declaration on the Conduct of Parties in the South China Sea while the Code of Conduct negotiations are ongoing.) 

Setting aside the case of China, the tribunal’s ruling in Philippines v. China is also at variance with the U.S.’s interpretation of the standing of “historic rights” in maritime law. In its December 2014 Limits in the Seas analysis of China’s “dashed-line” claim, the U.S. State Department study had observed that “a State may not derogate from the Convention’s provisions on such [fisheries-related] matters by claiming historic waters or historic rights under ‘general international law.’” The State Department doubles down on this point in its January 2022 study of China’s South China Sea claims (Limits in the Seas No. 150). It observes at some length that:

the law of the sea does not permit th[e] entitlements [of coastal states of a large semi-enclosed sea] to be overridden by another State’s maritime claims that are based on “history.” To the contrary, a major purpose and accomplishment of the Convention is to bring clarity and uniformity to the maritime zones to which coastal States are entitled.

Beyond a narrow category of provisions relating to history or the traditional uses of the sea (Articles 10, 15, 51, and 62(3)), the study goes on to note that the convention is comprehensive in scope and “leave[s] no room for claims by any State that derogate from the rights of a coastal state” with respect to the latter’s exclusive maritime zones. Reaching beyond the convention and taking recourse to customary international law to justify a “historic right” that is plainly absent in the text of the convention is impermissible, the State Department study concludes. 

This reasoning appears plausible on the surface. But in light of past and present law of the sea jurisprudence, is it legally tenable? On both key counts—whether a state can reach beyond the text of UNCLOS to general or customary international law, and whether the latter can override the former—jurisprudence is more nuanced and, frankly, not supportive of Washington’s position. 

In Philippines v. China, the tribunal offered this definition of the term “historic rights”: 

[The term] is general in nature and can describe any rights that a State may possess that would not normally arise under the general rules of international law, absent historical circumstances. Historic rights may include sovereignty, but may equally include more limited rights, such as fishing rights or rights of access, that fall well short of sovereignty. (Emphasis added.)

The tribunal later went on to note that traditional fishing rights, acquired through long usage, were protected under international law. Such traditional fishing rights “constitute a vested right, and the Tribunal considers the rules of international law on the treatment of the vested rights of foreign nationals to fall squarely within the ‘other rules of international law’ applicable in the territorial sea.”

Continuing in this vein, the tribunal pointed out that in the territorial sea, “Article 2(3) [of the convention] contains an obligation on States to exercise their sovereignty subject to ‘other rules of international law[.]’” As a result, the coastal state in the Scarborough Shoal (China) was legally obliged to respect the traditional fishing rights of foreign (Filipino) fishermen within its territorial sea—an obligation that Beijing had failed to discharge. In effect, the court was saying that a state (the Philippines, in this case) could employ the text of the convention to derive a “historic right” (traditional fishing rights) from the body of general or customary international law (the “other rules of international law”). And that these “other rules of international law” could override or, at minimum, coexist with another state’s exclusive entitlements at sea (China’s territorial sea entitlements in the Scarborough Shoal). 

Both of these points challenge the U.S.’s interpretation that UNCLOS is comprehensive in scope and that a user state may not override a coastal state’s entitlements with a history-based claim that is founded in general international law.

The tribunal in Philippines v. China may have caught many legal specialists off guard, but its reasoning is neither abrupt nor unexpected. There is prior precedent. In Republic of Mauritius v. United Kingdom, the court had judged that “[s]tates may possess particular rights … by virtue of bilateral agreements or local custom … [and] that the Articles [of UNCLOS] were not intended to interfere with such [local custom or tradition-based historic] rights.” The multilingual terms of the convention and its negotiating history had confirmed that states in fact bore a positive “obligation to exercise their sovereignty subject to the[se] ‘other rules of international law’”—to which traditional or historic fishing rights belong.

And earlier, in the two-stage State of Eritrea v. Republic of Yemen arbitration of the late 1990s, the tribunal—alluding to the traditional openness of southern Red Sea marine resources for fishing—had even gone so far as to observe that there “are important elements capable of creating certain ‘historic rights’ [in maritime zones.] … [T]hese special factors constitute a local tradition entitled to the respect and protection of the law … and by its very nature, [this traditional fishing regime] is not qualified by the maritime zones specified under the United Nations Convention on the Law of the Sea.”

Successive tribunals seated after UNCLOS came into effect have quashed any discrepancy over whether a historic right based on customary international law, such as traditional fishing rights and rights of access, can or cannot coexist in the exclusive maritime zone of a coastal state. Such rights unquestionably can. These rights are acquired rights of a private nature akin to property rights, are formed over the long course of history, vest with their state, and are capable of being exercised nonexclusively in the exclusive maritime zone of a coastal state.

A discrepancy does continue to exist over the geographic scope of enjoyment of this customary law-based right. In Eritrea v. Yemen, the court had observed that traditional fishing rights “were not qualified by the maritime zones specified under the United Nations Convention on the Law of the Sea” and obtained in the territorial sea and EEZ of the coastal state. In Philippines v. China, the court took an opposite tack and limited such third-party rights to only the territorial sea of the coastal state, observing that it did “not consider it possible that the drafters of the Convention intended for traditional or artisanal fishing rights to survive the introduction of the exclusive economic zone.”

Clearly, a legitimate debate remains to be had over the geographic scope of enjoyment of such traditional fishing rights in the exclusive maritime zones of a coastal state in a semienclosed sea. Article 123 of UNCLOS does after all enjoin coastal states fringing a semienclosed sea, such as the South China Sea, to “endeavor … to coordinate the management, conservation, exploration and exploitation of the living resources of the sea.” And as for China, if it wishes its “historic rights” claims to enjoy a modicum of support in the international community, it should first spell out clearly that it seeks no more than a nonexclusively exercisable traditional fishing right in the South China Sea. Commercial fisheries and oil and gas development rights beyond the geographic range of its EEZ simply cannot and will never make the cut as an UNCLOS-protected “historic right.”

Sourabh Gupta is a resident senior fellow at the Institute for China-America Studies in Washington, D.C.

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