More on China-Philippines UNCLOS arbitration

I blogged a few days ago about China's purported rejection of arbitration under UNCLOS of the Philippines' complaint over the Nansha islands. After speaking with colleagues who are international law specialists, I can add a bit more to the following paragraph:

As I read the Xinhua report of China's rejection, China also seems to be arguing that the Philippines is precluded from bringing this type of action because of obligations it has undertaken in other international agreements, specifically, the Declaration on the Conduct of Parties in the South China Sea. For this argument to work, it would have to be true that (a) the Philippines has indeed undertaken contradictory obligations, and (b) those obligations, under international law as recognized by the UNCLOS arbitral tribunal, will trump its rights under UNCLOS. I have no informed (or even uninformed) opinion about whether either part of this argument is sound. But I suspect that these questions must themselves be resolved in the arbitration proceedings.

It is theoretically possible that Country A could have rights against Country B under Treaty X, but has waived those rights under Treaty Y. This is what China is in effect arguing - that even if UNCLOS gives the Philippines a right to arbitration with China (and perhaps even the right to win the arbitration, although of course China would never admit even that hypothetical), it has waived that right by signing on to the Declaration of Conduct (the "DOC").

Here's the problem with that argument. First, it doesn't work in substance. Even if seeking arbitration under UNCLOS did violate a commitment made in the DOC - a very questionable proposition - the Declaration of Conduct does not amount to a formal treaty commitment of the kind that could override a contrary right to arbitration under UNCLOS. But hey - maybe you think that's not crystal-clear. What is crystal-clear is the second point, though: that the argument doesn't work procedurally. Parties don't get to judge the merits of their own arguments. China's argument about the effect of the DOC, like its argument about subject-matter jurisdiction (should it choose to make it) is one that must be made before the UCLOS arbitral tribunal, which has the power to decide its own jurisdiction.

In short, no matter how strong China's case is, it's one that has to be argued before an UNCLOS arbitral tribunal if another UNCLOS member starts proceedings. By joining UNCLOS, you agree to this procedure even in cases you think are frivolous. Is there anyone explaining this to the Standing Committee of the Politburo? They seem to understand it well enough when it comes to the WTO.