The Philippines, on the basis of historic right of title, claims that its territorial sea extends to the limits set forth in the colonial treaties, which define the extent of the archipelago at the time it was ceded from Spain to the U.S. in 1898. The line drawn around the archipelago marks the outer limits of the historic territorial seas of the Philippines, which will be referred to here as the Philippine Treaty Limits. The Philippine Treaty Limits are contested in international law because they evidently breach the twelve-mile breadth of the territorial sea provided for in the Law of the Sea Convention, which the Philippines signed and ratified.
The Philippine Treaty Limits are almost universally contested and seemingly irreconcilable with conventional and customary international law. This paper will clarify the historical context, extent, and basis of the Philippine Treaty Limits. The international legal status of the Philippine Treaty Limits, which is a far more complex issue, will not be covered in this paper.
This paper is in four parts. Part I discusses the international legal norm of territorial integrity and provides a brief outline of the development of the Philippines as a nation-state. Part II discusses the cession of the Philippines from Spain to the U.S. by looking at state succession in international law and examining the colonial treaties which collectively defined the Philippine Treaty Limits. Part II also analyzes the nature and defects of the Spanish and American titles over the Philippines. Part III illustrates the extent of the territorial boundaries claimed by the Philippines based on historic title by treaty, explains the juridical function of these lines from a municipal point of view, and discusses historic rights in international law and the basis of the Philippine historic right of title to its Treaty Limits. Part IV concludes with a discussion of the Philippines’ burden of proof to overcome challenges to the validity of its territorial limits in international law.