Nicaragua’s cases brought a great contribution to the law on intervention. They clarified some of its characteristics, the most important of which relating to the statutory nature of intervention: thus, the admissibility of these proceedings is not dependent upon the consent of the Parties, but on the fulfilment of the conditions established by the Statute. Though the Court took many years to acknowledge this fundamental aspect, its case-law seems now stabilized—at least as a matter of principle. The same cannot be said about the substantive conditions for admissibility of intervention: absent any real attempt from the Court to define the concept of ‘interest of a legal nature which may be affected’, the admission of intervention under Article 62 is still highly circumstantial. These ambiguities also durably impacted the consequences of intervention. The Court firmly maintains a peremptory distinction between intervention as a party and intervention as a non-party, but it also deprives it of any prospect of clarification, since it has never admitted intervention as a party. This emphatic insistence does not help clarifying the status of the intervener, nor does it stimulate the reflection upon its procedural rights and obligations.