What experts say

The US Navy, the strongest in the world, will go wherever it wishes. There are hostile forces in the United States, and they worked together with the Philippines to make the arbitration case. The United States is not part of the UNCLOS, but China has been a part of it. The Philippine leadership made a mistake and misjudgment.

Zheng Yongnian, director of the East Asian Institute at National University of Singapore

Although the Philippines has not asked the tribunal to determine the sovereignty of the maritime territories involved, essentially the question before the tribunal concerns territorial sovereignty, and the tribunal is not entitled to decide such questions. China, in its declaration on becoming a party to UNCLOS, excluded third-party compulsory arbitration with regard to those issues which the tribunal is being asked to rule on by the Philippines. A declaration by a state party to a treaty remains in effect until it is withdrawn by the state which made it.

Abdul Gadire Koroma, former judge at the International Court of Justice

Keyuan Zou, Harris Professor of International Law at the University of Central Lancashire

You cannot have arbitration if one side says it does not participate, because arbitration is between two parties who want to participate. This is particularly ridiculous when it comes to the United States, because it does not adhere to a large number of international treaties. It is ridiculous that the United States comes to the South China Sea, about 8,000 km from the US shore for political motives. It's deliberately trying to create problems.

John Ross, a columnist in Britain and former deputy mayor of London

Questions of territorial sovereignty are governed by general international law, not by the law of the sea convention, from which the tribunal derives its jurisdiction. There is no enforcement mechanism for awards rendered by tribunals established under the law of the sea convention. Enforcement will depend on the parties to the dispute. China has made it clear it will not accept any award rendered.

Stefan Talmon, professor of international law at the University of Bonn