ABSTRACT
Intervention is an incidental proceeding by which the International Court of Justice (ICJ) can declare the participation of a third state admissible in a case between two other litigant states. The general purpose of intervention is to allow the Court to protect the interests of third states that may be affected by its decision and, therefore, improve the judicial settlement of multilateral disputes. However, at the international level litigation is still generally perceived as
a private business between the parties, and third-state intervention is mostly regarded as an intrusion rather than a means to ensure a better settlement of a common dispute. There are certainly exceptions: in particular, the participation of third parties is increasingly secured before judicial bodies established by international regional organizations in cases where one of the member states or the organization is involved. This tension between private and collective interests largely explains why
for years the rules governing intervention have been unclear and the relevant jurisprudence of the Court has been reluctant to elaborate on the requirements of intervention.1 The compromise formula, which was originally inserted in Article 62 of the Permanent Court of International Justice’s Statute and was later maintained in the ICJ Statute, was intentionally drafted in very general terms as no agreement could be found on a number of issues ‘leav[ing] them to be decided as and when they occurred in practice and in the circumstances of each particular case’.2 Inevitably, this uncertainty has not prompted third states to ask permission to intervene in cases brought before the Court; they have generally found other ways to bring to the attention of the Court their interests that might have been affected by one of its decisions. Article 62 has been invoked in ten cases by 14 states and three
states have been granted permission to intervene. In its case law, the Court has adopted a rather restrictive approach; it has clarified some controversial aspects of intervention, but it has left others still unsettled. After a brief overview of the basic rules governing intervention, the
following analysis will focus on two cases involving Latin American states. They are particularly useful for explaining the approach taken by the Court with respect to both the aspects of intervention: those that are today no longer controversial; those that still require further clarification.
