It is doubtful whether the IJC intended to establish a rule of GIL in requiring, Nottebohm, that there must exist an effective link between the person and the state in order that the latter may exercise its right of diplomatic protection in behalf of the former.
The theory of effective or active nationality was established in the law of nations for the purposes of settling conflicts between two national states regarding persons simultaneously vested with both nationalities, in order to decide which of them is to be dominant, whether that described as nominal, or that describe as effective or active, confirmed by elements of fact. When a person has only one nationality the theory of effective nationality cannot be applied without the risk of causing confusion.
The Tribunal found that the claimant was not US national so neither ‘UN national’. In fact he had been German but had forfeited his German nationality in 1940 under German law and was a stateless