Island of Palmas Case (Netherlands v United States of America)

Facts

• The USA claimed sovereignty over the Island of Palmas (Miangas) as successor to Spain, which had discovered the island
• The Netherlands had exercised continuous, peaceful administration over the island for over 200 years
• Dutch activities included establishing suzerainty agreements with local rulers, displaying the flag, and exercising jurisdiction
• Spain's claim rested solely on discovery in the 16th century, with no subsequent effective occupation
• The USA inherited Spain's claim through the Treaty of Paris 1898

Issue

1. Whether Spain's title through discovery or the Netherlands' title through continuous peaceful exercise of state authority prevailed as the basis for sovereignty over the Island of Palmas.

Held

• The arbitrator found in favour of the Netherlands
• Discovery alone creates only an inchoate title
• An inchoate title must be completed by effective occupation within a reasonable time
• Continuous and peaceful display of state authority is superior to a bare claim of discovery
• The intertemporal law principle applies: title must be assessed both by the law at the time of acquisition and maintained by the law as it evolves

Ratio Decidendi

Sovereignty in the relations between states signifies independence, the right to exercise therein, to the exclusion of any other state, the functions of a state. A title based on discovery is merely an inchoate title which must be completed within a reasonable time by effective occupation. Continuous and peaceful display of state authority over territory is as good as title. Where two claims conflict, actual continuous exercise of sovereignty prevails over a dormant historical claim.