"For these reasons": the practice of justification of the International Court of Justice

This thesis examines the practice of justification of the International Court of Justice (‘ICJ’ or ‘the Court’). While mostly to be found in the reasons, the Court’s justificatory effort is not confined to their indication. In addition to the reasoning set out in judgments and advisory opinions, the Court uses a range of tools—some extrajudicial—to support or clarify its decisions: speeches at the United Nations, presentations to the International Law Commission, press releases, and social media communications. Within its decisions, elements such as aesthetic choices, formal structure, and obiter dicta also contribute to this practice. For the ICJ, justifying is thus not only a legal obligation under Article 56 of its Statute, but a broader discursive effort shaped by argumentative strategies, form, style, and communication. Through close readings of all advisory opinions and judgments of the Court and interviews with former ICJ staff, this thesis explores how the ICJ’s practice of justification, composed of its different phases of ‘rationalizing’, ‘structuring’ and ‘sharing’, far from being a mere exercise in logically applying law to the facts, might ultimately shape and reinforce the understanding of the Court’s perception and self-perception of its role.