## Facts

- The Island of Palmas (Miangas) is a small island between Mindanao and the Talaud Islands, with limited economic or strategic value.
- Spain ceded the Philippines to the United States in the 1898 Treaty of Paris; the treaty’s boundary lines enclosed Palmas.
- In 1906, U.S. officials learned Dutch authorities asserted sovereignty over Palmas, prompting diplomatic dispute.
- The United States claimed title mainly as Spain’s successor, relying on Spanish discovery, historical cartography, and the Treaty of Paris cession; it also argued proximity to the Philippines supported title (contiguity).
- The Netherlands claimed sovereignty based on long-standing Dutch authority from at least the late 17th century, including acts of the Dutch East India Company, agreements with local rulers, and administrative manifestations of control.
- By Special Agreement of January 23, 1925, the parties submitted a single question to a sole arbitrator (Max Huber) to decide whether Palmas belonged to the United States or to the Netherlands.

## Issues

1. Whether Spain’s asserted discovery-based claim (and the Treaty of Paris cession to the United States) established sovereignty over Palmas.
2. Whether the Netherlands acquired or confirmed sovereignty through a continuous and peaceful display of state authority over the island.
3. Whether geographic contiguity to the Philippines could independently establish or strengthen the United States’ territorial title.
4. How intertemporal law affects evaluation of historic claims and the continued validity of territorial title over time.
5. What evidentiary weight should be given to maps, private company conduct, and agreements with local rulers in proving sovereignty.

## Decision

- The arbitrator awarded sovereignty over the Island of Palmas to the Netherlands.
- Spain’s discovery-based claim was treated as, at most, an incomplete title that required subsequent effective occupation or administration to mature into sovereignty.
- The Netherlands’ long, continuous, and peaceful display of authority over the island constituted a superior title.
- The Treaty of Paris could not transfer to the United States more rights than Spain possessed; because Spain lacked valid sovereignty over Palmas in 1898, the cession did not establish U.S. title.
- Contiguity was rejected as an independent legal basis capable of overriding established title grounded in effective control.

## Legal Principles

- A discovery-based claim, without subsequent effective occupation or administration, is insufficient to prevail against a definite title shown by continuous and peaceful display of sovereignty.
- Territorial sovereignty is demonstrated through effective, public, and ongoing exercise of state functions to the exclusion of other states, maintained peacefully vis-à-vis other states.
- Intertemporal law requires evaluating the creation of rights under the law at the time of the relevant historical acts, while assessing the continued existence of rights in light of later legal developments.
- Cession cannot convey better title than the ceding sovereign possesses.
- Maps are generally secondary evidence and do not by themselves prove territorial title absent supporting acts or materials.
- Acts of a chartered company may be attributable to a state for sovereignty purposes when the company functions as a state instrument in the relevant respect.
- Agreements with local rulers may be probative manifestations of sovereignty when they reflect an asserted and exercised authority in the territory.

## Conclusion

The arbitral award held that the Netherlands, not the United States, possessed sovereignty over Palmas because long, uncontested, and effective Dutch authority outweighed Spain’s incomplete discovery-based claim and the United States’ reliance on treaty boundary lines and geographic proximity.


Island of Palmas (U.S. v. Neth.), 2 R.I.A.A. 829 (Perm. Ct. Arb. 1928)