Mariposa Development Company Case Panama US claim commission 6 UNRIAA 338

The claim is on behalf Mariposa Development Company and is based on alleged unlawful expropriation by Panamanian authorities of a tract of land called El Encanto. The Commission was set up by a convention, and the exchange of ratification took place on 3 October 1931 In 1917 it was enacted a Panamanian Expropriation legislation. Based on such Act, there were judicial actions against the property of the claimants. The first courts gave them the reason, but in 20 October 1931 the Supreme Court of Panama hold that El Encanto was national property. Panama contended that the alleged damages was not sustained by the claimants prior the exchange of ratifications and the Commission had no jurisdiction

In order to establish jurisdiction the commission had to determine the date at which a dispute arising from the application of Panamanian Expropriation legislation to a US company, had come into existence. It held that the dispute came into existence not when the legislation was enacted but only when it was enforced ‘A claim for the expropriation of property must be held to have arisen when the possession of the owner is interfered with and not when the legislation is passed which makes the later deprivation of possession possible’ ‘Practical common sense indicates that the mere passage of an act under which private property may later be expropriated without compensation by judicial or executive action should not at once create and international claim on behalf of every alien property holder in the country’