## Facts

- Clipperton Island is a small, uninhabited coral atoll in the Pacific Ocean roughly 1,000 km southwest of Mexico.
- In early 1858, France granted a concession to exploit guano resources on the island.
- On Nov. 17, 1858, a French naval officer, acting under commission, proclaimed French sovereignty from a vessel offshore; there was a brief landing, but no permanent marker or administration was established on the island.
- France notified its act through diplomatic channels (including the French consulate in Honolulu) and publicized it locally in Hawaii.
- Mexico asserted competing claims, including a 1897 landing and hoisting of the Mexican flag.
- In 1905, Mexico established a military garrison and later constructed a lighthouse pursuant to presidential orders; by 1914 about 100 Mexican settlers lived on the island.
- During the Mexican Revolution, resupply stopped; many occupants died, and surviving settlers were rescued and returned to Mexico by 1917.
- France and Mexico agreed by compromis signed in 1909 (ratified in 1911) to submit the sovereignty dispute to arbitration by Victor Emmanuel III, King of Italy.

## Issues

1. Whether Mexico proved sovereignty through succession to a Spanish historic title based on alleged Spanish discovery and possession.
2. Whether France acquired sovereignty by occupation through its 1858 acts despite a lack of continuous, visible administration.
3. Whether France lost any acquired title by abandonment (derelictio) due to prolonged inaction, and whether Mexico’s later garrisoning and settlement could displace France’s earlier claim.

## Decision

- The sole arbitrator awarded sovereignty over Clipperton Island to France.
- Mexico failed to establish a Spanish-based historic title because it did not show Spain effectively incorporated or exercised sovereignty over the island.
- France’s 1858 proclamation and related notifications were treated as a clear manifestation of intent to occupy and, given the island’s uninhabited character and lack of competing effective claims at that time, were sufficient to complete occupation.
- Mexico’s later acts (flag-raising, garrison, lighthouse, settlement) were considered incapable of defeating a pre-existing, perfected French title.
- France did not lose sovereignty by derelictio because there was no showing of intent to abandon, and non-exercise of authority did not forfeit a definitively perfected acquisition.

## Legal Principles

- Discovery, without effective incorporation or exercise of authority, does not by itself confer territorial sovereignty.
- Occupation requires intent to occupy (animus occupandi) and an actual taking of possession shown by acts asserting exclusive authority; the necessary intensity of acts depends on the nature of the territory.
- For completely uninhabited territory at the absolute and undisputed disposal of the claimant state at the moment of assertion, modest acts clearly manifesting sovereignty may suffice to complete occupation without establishing a permanent local administration.
- Once territorial title is definitively perfected, it is not lost through mere inaction or absence of continuous administration absent clear intent to abandon (animus derelinquendi) or a valid, superior adverse title.

## Conclusion

The arbitral award held that France validly acquired sovereignty over an uninhabited island through clear acts of occupation in 1858 and retained that sovereignty despite long periods of inactivity; Mexico’s historic-title theory and later on-island administration were insufficient to defeat France’s perfected title.


Sovereignty Over Clipperton Island (Fr. v. Mex.), 26 Am. J. Int’l L. 390 (1932)