Ruling Trips Military Alert in the South China Sea

A Filipino soldier patrols the shore of Pagasa Island (Thitu Island) in the Spratly group of islands in the South China Sea, west of Palawan, the Philippines, on May 11, 2015. Joshua Kurlantzick writes that if a tribunal rules against China on the Philippines’s legal case against China’s claims in the South China Sea and Beijing responds with a show of force, it will be a critical test of how far the U.S. will go to support its allies. Ritchie B. Tongo/Pool/reuters

This article first appeared on the Council on Foreign Relations site.

An international tribunal in The Hague is expected to deliver on Tuesday its verdict on the Philippines's legal case against China's claims in the South China Sea.

Under the previous Aquino administration, Manila launched a case at the Permanent Court of Arbitration tribunal, asking for it to rule on whether China's nine-dashed line claim in the South China Sea was legal under international maritime law and whether other aspects of Beijing's claims were legal.

Although few other countries paid attention when the case was taken up by the court last year, Vietnam has now rhetorically supported the Philippines's right to a hearing.

The Obama administration increasingly has seen the case as a way to demonstrate that U.S. partners obey international law in the South China Sea while Beijing does not. Indeed, while senior Obama administration officials said little about the case last year, in recent weeks they have repeatedly mentioned it, warning Beijing not to launch provocative actions after the ruling and emphasizing that the court is a neutral decider.

The new Rodrigo Duterte administration, though potentially more open to bilateral negotiations on the South China Sea than Benigno Aquino's administration was, has continued to support the Philippines's right to seek a ruling in The Hague.

China is not actually participating in the case, rejecting any third-party efforts to resolve South China Sea disputes. Yet although China has said that it rejects the court's jurisdiction and will not heed any ruling made, Beijing seems to have become increasingly skittish that the court is going to rule against it.

A ruling could not really be enforced, but it would give the Philippines legitimacy and leverage in dealing with China. Also, a ruling against China's claims possibly would strengthen the claims of other countries, like Vietnam, Malaysia and Brunei, to the South China Sea. It is very likely that the tribunal will rule against Beijing.

In recent months, China has apparently exerted significant pressure on Cambodia, Malaysia and Thailand, plus other members of the Association of Southeast Asian Nations it considers potential allies, to prevent ASEAN from releasing a consensus statement about the ruling. Beijing also has used state media and other outlets to publicly cast doubt on the court's legitimacy before the ruling is released.

If the ruling goes against China and Beijing responds with a show of force in the South China Sea—clearly increasing the pace of building on man-made islands or declaring an air defense identification zone (ADIZ) in the South China Sea, for instance—it will be a critical test of how far the United States will go to support its allies and partners with South China Sea claims.

The declaration of an ADIZ would be particularly provocative, but it should not catch the United States and its partners off guard, since Beijing has been threatening to announce an ADIZ in the South China Sea for months now. When China announced an ADIZ in the East China Sea in 2013, it came as something of a surprise to both U.S. and Japanese forces.

The stakes in the South China Sea, of course, are enormous. In advance of the ruling and the potential aftermath, here is a link to the Contingency Planning Memorandum I wrote for the Council on Foreign Relations last year. It examines several potential warning signs of emerging conflict in the South China Sea, as well as signs of other types of conflict between China and its Southeast Asian neighbors.

Joshua Kurlantzick is senior fellow for Southeast Asia at the Council on Foreign Relations.