A basic fact oft overlooked is that international law operates differently from domestic law. “Sovereignty” plays a huge part in this. In relation to territorial claims, resolution by treaty or customary law, as well as third-party institutions, come in terms of other States’ recognition but not actual conferment of ownership. Effectively, the States claimants do that among themselves.

Put another way, the ownership of territory is what the State claimant declares it to be.

This is particularly true of the July 2016 Philippines v. China Permanent Court of Arbitration South China Sea ruling, which essentially glossed over questions of ownership and instead focused on:

a) The 9 Dash Line: the Tribunal concluded the same is “contrary to the Convention and without lawful effect… [and] that the Convention superseded any historic rights or other sovereign rights or jurisdiction in excess of the limits imposed therein.”

http://www.bworldonline.com/content.php?section=Opinion&title=the-challenge-of-winning-over-china&id=137872