The relevant rule flows from Nottembohm, the rule of real and effective nationality, and the search for stronger factual ties between the person concerned and one of the states whose nationality is involved.
The tribunal has jurisdiction over claims against Iran by dual Iran-US nationals when the dominant and effective nationality of the claimant during the relevant period from the date the claim arose until 19 January 1981 was that of the US. In determining the dominant and effective nationality the tribunal will consider all factors, including habitual residence, centre of interest, family ties, participation in public life and other evidence of attachment
To this conclusion the Tribunal adds an important caveat. In cases where the tribunal finds jurisdiction based upon dominant and effective nationality of the claimant the other nationality may remain relevant to the merits of the claim. There is precedent for denying jurisdiction on equitable grounds in cases of fraudulent use of nationality. When an individual disguises his dominant and effective nationality in order to obtain benefits with his secondary nationality (Flegenheimer)