BRUSSELS, Belgium—The decision by a United Nations tribunal on the case that the Philippines brought before it concerning disputed territories in the West Philippine Sea will serve as a guide for how the Philippines can negotiate with China on the issue, according to a maritime security expert.

While the Chinese government and commentators have denounced the move, the Philippines’ filing of a case against China with the International Tribunal on the Law of the Sea (Itlos) was not a “bad idea,” said Jane Chan Git Yin.

After all, international law acts as a “leveling ground” for puny countries dealing with bigger neighbors, said Yin, research fellow-coordinator of the maritime security program at Nanyang Technological University.

“I don’t think it’s a bad idea to have the tribunal rule on the application of Unclos (UN Convention on the Law of the Sea),” she said in an interview. “The fact of the matter is that Unclos is intentionally vague on some of these issues.”