Key points for reflection:

• Basic principle: Nationality is the basis for legal interest due to the Vattelian fiction: ‘an injury to the national is an injury to the State’—Mavrommatis Palestine Concessions, PCIJ
• Legal interest of a State as a prerequisite to admissibility
• Basic principle: only claimants with a demonstrable interest may bring an action in respect of a wrong (South West Africa)
• Exceptions where a plurality of States may be concerned:
• Obligations erga omnes partes (ICJ 2012 and 2013 cases)
• Violation of jus cogens norm?
• Precondition: local remedies must be exhausted
• Only applicable when interest is preponderantly of a national and not of the State itself
• Diplomatic protection as giving rise to basic obligations on the treatment of aliens