Right now in the Western Pacific, Taiwan is mired in two disputes over the legal status of an island. These claims hinge on the very definition of an island under the United Nations Convention on the Law of the Sea, and their outcome stands to influence the way maritime business is conducted the world over.

At The Hague, the Philippines is in the middle of an arbitration case against mainland China. As part of its argument, Manila is attempting to downgrade to the status of a mere rock Taiwan’s Taiping Island (also known as...