July 12, 2016, marked a turning point in the long-standing disputes over the South China Sea. After more than three years of proceedings at the Permanent Court of Arbitration, an international body in The Hague, a tribunal constituted under the UN Convention on the Law of the Sea (UNCLOS) issued a widely anticipated decision in a case the Philippines brought in 2013 to challenge China’s maritime claims to most of the contested waterway.

Many observers had expected the tribunal to rule in Manila’s favor. They’d also expected China to reject the tribunal’s decision, since Beijing, a signatory to the convention, has long opposed the proceedings and had warned that it would not abide by the judgment. But few anticipated a ruling as definitive as the one ultimately handed down. The tribunal ruled in favor of the Philippines on almost every count, declaring nearly all of China’s maritime claims in the region invalid under international law.

In so doing, the tribunal has brought a substantial amount of new clarity to a number of contentious legal issues and has set precedents that will affect the law of the sea for years to come. But it has also created an immediate problem: China’s defeat was so crushing that it has left Beijing few ways to save face. Chinese officials may feel that the tribunal has backed them into a corner—and respond by lashing out. That’s especially problematic because international law has no simple enforcement mechanism, so if China decides to defy the tribunal, neither it, nor the Philippines, nor any other interested states will be able to do much to induce China to cooperate. Washington and its local partners can still avoid a dangerous escalation, but only if they encourage China to abide by the ruling while making clear to Beijing that it has not been trapped by it.

A protest over the disputes in the South China Sea outside the Chinese consulate in Metro Manila, June 2015.
A protest over the disputes in the South China Sea outside the Chinese consulate in Metro Manila, June 2015.


The tribunal’s ruling was striking for several important reasons. First, in a surprising move, the tribunal held that all the territories in the contested Spratly Islands are reefs or rocks, not islands. That distinction matters, because under UNCLOS, reefs cannot generate a claim to the surrounding waters or airspace, and rocks can serve as the basis for only a small maritime claim of 12 nautical miles. Islands, on the other hand, generate a 200-nautical-mile exclusive economic zone; states can also assert additional rights based on the extent of the continental shelves that underlie them. China insists that it has sovereignty over the Spratly Islands, and the tribunal did not rule on their rightful ownership. But by declaring all of the Spratlys’ features to be reefs or rocks, it significantly limited the claims China can make to the surrounding water and airspace. Under international law, China’s outposts in the (now misnamed) Spratly Islands should be considered isolated enclaves floating in a part of the ocean that is in the Philippines’ exclusive economic zone, since they lie within 200 nautical miles of that country’s territory. And Beijing cannot use the Spratlys to justify any claims to the surrounding waters.

Next, the tribunal found that China had conducted illegal activities inside the Philippines’ exclusive economic zone. Chinese vessels, the tribunal ruled, had fished where they shouldn’t have, had dangerously approached some Philippine boats, and had prevented others from fishing and extracting petroleum within the zone. Nor was this all: the tribunal also censured China’s construction of artificial islands in the region, which it determined had caused severe environmental damage and heightened geopolitical tensions.

Washington and its partners can still avoid a dangerous escalation.

Finally, the tribunal completely invalidated China’s claim that it holds historic rights to the South China Sea through its “nine-dash line,” a sweeping cartographic projection that encompasses as much as 90 percent of the waterway. The line was first unveiled by the Republic of China in 1947 and was adopted by China’s Communist rulers after they took power in 1949. Chinese officials have never explained the nine-dash line’s precise legal meaning, but they have repeatedly claimed that it demarcates an area from which China can extract resources. The tribunal found that there was no basis for the rights that Beijing said underpinned the line, and that even if there had been at some point, UNCLOS superseded those rights when China ratified it in 1996. 

The tribunal’s decrees decimated China’s maritime claims in the South China Sea and handed a great victory to the Philippines in the process. But this victory could prove a Pyrrhic one if China responds with increased belligerence.


As noted, most observers expected the tribunal to issue a ruling that generally favored the Philippines. But most also thought that it would leave China some room to maneuver. One way the tribunal could have done that would have been by implicitly invalidating the nine-dash line without definitively striking down China’s argument that it has historic rights in the region—by, for example, pointing out the line’s ambiguity and indicating that all of Beijing’s maritime claims must comply with UNCLOS.

Had the tribunal opted for such a “soft” repudiation, it would have given China a valuable opportunity to save face. In the wake of the ruling, Beijing could have formally defined the nine-dash line for the first time, reframing it as a narrow assertion of its enclaved territories and their maritime entitlements rather than an undifferentiated claim to the entire South China Sea. That would have brought China’s position in line with UNCLOS while allowing Beijing to suggest to its domestic audience that it was not backing down. But since the tribunal rejected China’s claims to historic rights in the waterway entirely, Beijing now must either continue to reject the tribunal’s ruling wholesale or offer the Chinese public a fresh explanation of why its rights still stand—a tough approach, since Chinese leaders have long stuck to exactly the narrative that the tribunal rejected.

The tribunal’s ruling that the Spratlys do not constitute islands under UNCLOS closed off another opportunity for Beijing to save face. Before the decision was handed down, it seemed probable that the tribunal was going to forgo issuing any kind of ruling on Itu Aba, a Taiwanese-held feature that seemed more likely than any other part of the Spratlys to be a candidate for the legal status of an island. If the tribunal had indeed avoided this question, it would have given China another off-ramp: since China maintains a claim to Itu Aba through its professed sovereignty over Taiwan, Beijing could have argued, at least to the Chinese public, that the reunification of China and Taiwan would eventually entitle it to Itu Aba and therefore to a large swath of the South China Sea. Indeed, the exclusive economic zone that would have extended from Itu Aba under such a scenario would have covered many of the Spratlys’ other contested features. By ruling that Itu Aba, like all the other features in the Spratlys, is not an island, the tribunal eliminated that possibility and destroyed China’s ability to justify its expansive claims to the South China Sea in legal terms.

Chinese dredging vessels around Mischief Reef in the disputed Spratly Islands, May 2015.
Chinese dredging vessels around Mischief Reef in the disputed Spratly Islands, May 2015.


China has rejected the legitimacy of the Philippines’ case and the tribunal’s jurisdiction to hear it since Manila first brought its complaint in January 2013. Beijing has decried the tribunal’s decision as illegitimate, and it will certainly not abandon its outposts in the Spratlys or return the sand it used to manufacture them to the seabed. In fact, in the wake of the ruling, China landed civilian aircraft on some of those outposts, presumably to demonstrate that possession is nine-tenths of the law.

China might now choose to flout the decision more explicitly by deepening its de facto control of the area. It could, for example, declare an air defense identification zone in the South China Sea, as it did in the East China Sea in 2013, unsettling many of its neighbors in Southeast Asia. It could also start to reclaim land at Scarborough Shoal, which it wrested from the Philippines in 2012. (Former U.S. officials have suggested that China might be preparing to do exactly that later this year.) Chinese forces could attempt to intercept a U.S. ship or plane as it conducts a freedom-of-navigation operation, raising tensions between Beijing and Washington. Or China could take actions that are less dramatic but nevertheless destabilizing. It could attempt to apply new domestic laws to the areas it controls. Or it could declare base lines, the formal points from which states measure maritime zones, around the Spratlys, suggesting another effort to administer the surrounding waters. 

Any of those actions would be deeply worrisome for China’s neighbors and would demonstrate that Beijing is uninterested in playing by the rules of the international order. Even more troubling, however, would be if a defiant and defeated China chose to withdraw from UNCLOS completely. It is possible for a country that is not a party to the convention to observe its provisions—the United States is the prime example. But if China withdrew, it would almost certainly portend Beijing’s rejection of the prevailing maritime order, setting the stage for further escalation of the many disputes regarding the South China Sea. China’s withdrawal from the convention would suggest not only that Beijing intends to ignore the tribunal’s ruling but also that it does not want to be bound by the many other maritime rights and provisions that UNCLOS enshrines and that govern the free use of the global commons. 

There are good reasons for China not to take such a course. First, although the tribunal dealt a blow to China’s maritime claims—its rights to water and airspace and its authority to conduct certain activities there—it did not rule on China’s claims to sovereignty over territory in the South China Sea, which are beyond the scope of UNCLOS. For that reason, Beijing can rightly argue that its sovereignty over the contested reefs and rocks it occupies has not been affected. It cannot legally continue to declare military zones in the water or airspace around the reefs it occupies, nor can it do so more than 12 nautical miles from the rocks it controls. But if Beijing emphasizes sovereignty claims instead of maritime ones, it could draw public attention away from its legal defeat.

Resolving the current showdown peacefully and legally would be in everyone’s interests—especially China’s.

Second, after several years of vigorous island building, Beijing has good reasons to avoid further alienating its neighbors. Many of those states—most notably the members of the Association of Southeast Asian Nations (ASEAN)—have become increasingly wary of Beijing in recent years and have clearly supported resolving the region’s disputes through the mechanisms of international law. Were China to make aggressive new moves, it would deepen their sense of alienation, encouraging them to strengthen their militaries to further balance against Beijing.

One other path could mitigate the sting of China’s defeat. The Philippines’ new president, Rodrigo Duterte, has signaled that he is interested in pursuing a more conciliatory approach to Beijing and has held out the possibility of resuming negotiations with China over resource sharing in the South China Sea. If Chinese President Xi Jinping accepts Duterte’s offer, he might be able to reach a deal with Manila that allows China to continue to claim some rights to resources in the far corners of the South China Sea.


Satisfying as the tribunal’s decision may be for Manila, all parties now have a strong stake in ensuring that the situation doesn’t escalate. The judgment sets a significant legal precedent: the principles that guided the tribunal’s decision are now part of international law, and countries must embrace and reinforce them if they want others to uphold them in the future. The case concerned just a few of Asia’s many maritime disputes. Other countries, from Japan to Vietnam, are considering cases of their own, and the tribunal’s judgment must produce some positive change if they are to pursue their own arbitrations with confidence. And although the South China Sea disputes have deep historical roots, they have flared up in recent years because China’s growing military capabilities have meaningfully improved Beijing’s ability to press its claims. If China goes further by deliberately flouting the ruling or withdrawing from UNCLOS, it could destroy the maritime order it has already damaged. 

There are several steps that the United States and its partners can take to reinforce the recent ruling without getting China’s back up. For starters, the United States and like-minded countries around the world should continue to declare their support for the legal process, calling on China and the Philippines to abide by it without taking a position on the underlying sovereignty disputes. The U.S. State Department should work closely but quietly with other claimants that are considering bringing cases of their own to help them ascertain how this ruling might affect their efforts. And the United States should make clear that it will investigate the implications of the decision for its own island claims.

The U.S. Department of Defense, for its part, should resume freedom-of-navigation operations that reinforce the decision after a pause of several weeks to allow tensions to cool. It should conduct those operations without pomp or fanfare: their message should be legal rather than military, and their audience should be Beijing.

Finally, U.S. officials should work closely with their Chinese counterparts, encouraging them to negotiate with the South China Sea’s other claimants, particularly the Philippines, and to make progress on a binding code of conduct with ASEAN, a long-sought multilateral agreement that would create a strict set of guidelines for behavior in the South China Sea. A code of conduct would likely also freeze the waterway’s political and territorial status quo, helping China reassure its neighbors that its long-term intentions are not threatening. U.S. officials should remind their counterparts in Beijing that these remaining avenues to negotiation will close if China makes another assertive move, such as beginning construction at Scarborough Shoal, but that if it does not, there will be ample room for cooperation between China and its neighbors and between Beijing and Washington. 

The United States and China should also press ahead with the confidence-building measures they agreed to at June’s U.S.-China Strategic and Economic Dialogue, to reduce the risk of an accidental clash between them. That would help each demonstrate to the other and to the region that neither wants to see a great-power conflict over the South China Sea or any other maritime issue and that both are committed to acting responsibly. More generally, U.S. officials should make clear that the arbitration decision has brought China to a legal crossroads, but that Beijing still has reasonable options available to it. Resolving the current showdown peacefully and legally would be in everyone’s interests—including, and especially, China’s.

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