Does the U.S. Have a Legal Obligation to Defend the Scarborough Shoal for the Philippines? Not Until It Decides Who Owns It.

As the tensions over the South China Sea continue to heat up, the Wall Street Journal editorial board has recently opined that the U.S. should state publicly that the U.S. “is treaty-bound to respond to an attack on Philippine ‘armed forces, public vessels or aircraft in the Pacific.’” (This argument has also been proposed by Gregory Poling, Zachary Cooper and Jay Batongbacal at AMTI.) But much to the disappointment of the Filipinos, Secretary of Defense Ash Carter did not offer such a public assurance during his recent visit to the Philippines. While the suggestion of a clarifying statement on the U.S.-Philippines Defense Treaty seems a good way to put pressure on China, and support a key ally in the region, the legal basis for a U.S. statement is more complex than the WSJ and others suggest. In fact, doing so would almost certainly require a serious shift in longstanding U.S. policy in the region.

Recently, rising tensions have begun to focus on Chinese plans to create another artificial island on “Scarborough Shoal (Huangyan Island)”. Scarborough is one of the most-disputed land features between the Philippines and China; it was the focal point of a physical confrontation between Chinese and Filipino ships in 2012 and it lies only 120 nautical miles from the main Philippines island of Luzon. U.S. naval jets recently conducted a fly-by of Scarborough Shoal, and the Chinese defense ministry has reiterated in response that the land feature is part of “China’s inherent territory.” Because it is so close to Luzon—and because leaked intelligence reports suggest China is planning to build an island and install military facilities there as soon as next month—it would seem crucial to clarify the U.S. defense obligations.

Although the U.S.-Philippines Mutual Defense Treaty requires the U.S. to respond to an armed attack on the Philippines’ military or coast guard forces in the Pacific, no such “armed attacks” are likely to occur. Rather, the Chinese are building artificial islands on land features the Philippines also claims, such as the Scarborough Shoal. It seems doubtful that a Filipino naval assault on such Chinese-held islands, and a Chinese defense to such attacks, would constitute an “armed attack.” Rather, it appears more likely that a Chinese response would qualify as an exercise of “self-defense.” To be sure, as Poling and Cooper argue, an “unprovoked armed attack” would trigger the defense treaty, but would a Chinese defense of Scarborough Shoal be “unprovoked?” It is at least somewhat ambiguous whether the U.S. obligation extends to defending armed attacks provoked by the Philippines in disputed territory.

The WSJ points out that clarifying language from President Obama about how the disputed Senkaku Islands fall within the U.S.-Japan Defense Treaty seems to have reduced Chinese activity in the East China Sea. They suggest a similar clarification might also cause China to think twice before embarking on its predicted next island-building plan on the Scarborough Shoal (which is well within the Philippines’ 200-nautical-mile exclusive economic zone).

But this analysis overlooks the difference in language between the two treaties. While the U.S.-Japan Treaty obligates the U.S. to act in response to an armed attack “against [Japan] in the territories under the administration of Japan,” the U.S.-Philippines Treaty is limited to responding armed attacks “on the metropolitan territory of either of the Parties, or on the island territories under its jurisdiction in the Pacific.” The U.S.-Japan Treaty’s use of the phrase “under the administration of Japan” plainly meant to include more than simply those territories over which Japan had sovereignty. By contrast, the U.S.-Philippines Treaty limits U.S. defense obligations to the Philippines’ “metropolitan territory” and “island territories under [the Philippines’] jurisdiction in the Pacific.” Neither of these phrases would, in the first reading, lend itself to cover territory over which the Philippines has control but not sovereignty. Both the terms “metropolitan territory” and “island territories under its jurisdiction” strongly imply that the obligation only covers territory over which the Philippines is sovereign.

Why is this a problem for the WSJ’s recommendation? Because the U.S. has a long-standing policy not to take sides in disputes over sovereignty in the South China Sea. Sovereignty over territories like the Scarborough Shoal are plainly disputed by China. The U.S. agnosticism on sovereignty is reflected in its earlier decision to conduct FONOPs as innocent passage patrols. It will not accept or reject any country’s claim to sovereignty in the region.

So the U.S. could not follow the WSJ’s advice unless and until it takes a position on which country has sovereignty over the various disputed land features in the South China Sea. Once it does so, it can argue with sounder legal footing that it has a legal obligation to defend the Philippines’ “territories.” I think such a shift in U.S. policy is worth considering. Indeed, Professor Batongbacal makes a good argument that while the U.S. does not take position on sovereignty disputes, its past practice suggests that the U.S. believes it acquired title to the Scarborough Shoal from Spain and then transferred it to the Philippines. That may be, but the current U.S. government position is to lump Scarborough Shoal along with other land features as “sovereignty disputes” where it will not take sides.

So perhaps this whole episode, and emerging crisis, is the right time for the U.S. to shift gears. It should no longer blindly repeat its position about “not taking sides” in sovereignty disputes. Rather, the U.S. should take a stand and support sovereignty claims that are really strong and reject sovereignty claims that are really weak. But until it does make this policy shift, the legal basis for a “clarification” by the United States is premature.