The United States and the European Union warned China on Wednesday that it should respect an international court ruling expected later this year on its dispute with the Philippines over territory in the South China Sea.
China claims virtually all the South China Sea and rejects the authority of the Permanent Court of Arbitration in the Hague hearing the dispute, even though Beijing has ratified the UN Convention on the Law of the Sea on which the case is based.
Amy Searight, US deputy assistant secretary of defence for South and Southeast Asia, said the United States, the European Union, and allies like Australia, Japan and South Korea must be ready to make clear that the court's ruling must be binding and that there would be costs to China for not respecting it if it lost the case.
"We need to be ready to be very loud and vocal, in harmony together, standing behind the Philippines and the rest of the ASEAN claimants to say that this is international law, this is incredibly important, it is binding on all parties," she told a seminar at Washington's Center for Strategic and International Studies.
Searight said the message to China, if it did not respect a negative ruling, should be, "we will hold you accountable."
"Certainly, reputational cost is at stake, but we can think of other creative ways to perhaps impose costs as well," she said without elaborating.
The Hague tribunal has no powers of enforcement and its rulings have been ignored before. Manila has said the court may hand down a ruling before May.
China disputes South China Sea territory with several other members of the Association of Southeast Asian Nations (ASEAN) as well as the Philippines.
Klaus Botzet, head of the political section of the EU Delegation in Washington, said it was difficult to oppose world opinion.
"A joint Western, a joint world opinion, matters also for Beijing," he said.
"If we unanimously support that international law as formulated by the international tribunal in the Hague ... needs to be upheld, that’s a very strong message and will be very difficult to ignore," he said.
In unusually forthright language, Botzet said China's policy of military buildup was not in its interest.
"It’s investing much more in its military relative to its economic growth; it’s forcing its neighbours into alliances against itself; positions its neighbours otherwise wouldn't take and the return on investment on this policy is negative," he said.
The United States had exceptional military capabilities in the Asia-Pacific, Botzet said, adding that the European Union "strongly supports the American guarantee of international law in Asia."