What did the 2016 South China Sea ruling decide, and what did it leave open?

In July 2016 an arbitral tribunal under the UN Convention on the Law of the Sea decided a case brought by the Philippines against China about the South China Sea. Its ruling answered some questions and carefully avoided others, and that split is the whole lesson.

What it decided was about the sea, not about who owns the islands. The tribunal said it would not rule on any question of sovereignty and would not delimit any maritime boundary. But it found that China's claims to historic rights over maritime areas inside the "nine-dash line" have no lawful effect unless they are entitled under the Convention. It also found that none of the high-tide features in the Spratly Islands can sustain human habitation or an economic life of their own, so all are legally rocks that do not generate an exclusive economic zone or continental shelf. Mischief Reef and Second Thomas Shoal were found to be low-tide elevations that generate no maritime zones of their own.

China did not take part. It said the dispute was ultimately about sovereignty, not exploitation rights, and cited its 2006 declaration excluding such disputes from arbitration. The tribunal held that the case was admissible. China has rejected the ruling, as has Taiwan. As of November 2023, 26 governments support it, 17 issued generally positive statements without calling for compliance, and eight rejected it. The UN holds no position on the case or the claims.

So the ruling settles less than it may seem. China, Vietnam and others still claim the islands, and the tribunal left that question alone. What it did was set the limit on the sea: whatever the islands' owner, the Convention defines what a rock or a reef can generate.