In this latest episode of EJIL: Live! the Editor-in-Chief of the Journal, Professor Joseph Weiler, speaks with Professor Niels Petersen of the University of Münster, whose article, “The International Court of Justice and the Judicial Politics of Identifying Customary International Law”, appears in Volume 28, Issue 2 of the journal.
In the article, Professor Petersen explores International Court of Justice decisions confirming the existence of customary international law. The abstract of the article states that:
It is often observed in the literature on customary international law that the identification practice of the International Court of Justice (ICJ) for customary norms deviates from the traditional definition of customary law in Article 38 (1) lit. b of the ICJ Statute. However, while there are many normative and descriptive accounts on customary law and the Court’s practice, few studies try to explain the jurisprudence of the ICJ. This study aims at closing this gap. I argue that the ICJ’s argumentation pattern is due to the institutional constraints that the Court faces. In order for its decisions to be accepted, it has to signal impartiality through its reasoning. However, the analysis of state practice necessarily entails the selection of particular instances of practice, which could tarnish the image of an impartial court. In contrast, if the Court resorts to the consent of the parties or widely accepted international documents, it signals impartiality.
The EJIL:Live! discussion focuses on the principal empirical findings of the article, and Petersen’s novel conceptualization of those arguments in terms of “judicial politics”, explicable by the institutional constraints that the Court faces. This conversation offers a reflection on how this assessment of the jurisprudence could alter scholars’ normative conceptions of the Court’s decisions, particularly in regards to customary international law.