The Substantive Approach to the Rule of Law in the Jurisprudence of the International Court of Justice

Abstract

To achieve the goals of the United Nations, the rule of law must be upheld. The International Court of Justice (ICJ), in accordance with its Statute, plays a key role in establishing the rule of law and has developed this concept in its practical jurisprudence. The Court’s practice has evolved from a formalistic interpretation of the rule of law toward a substantive approach. In issuing judgments—which represent the most significant manifestation of the rule of law—the Court contributes to the legitimacy of the rule of law by identifying legal norms and, at times, through changing its precedent or applying broad interpretations. The central question of this study is how the ICJ’s substantive approach can contribute to the development and legitimacy of the rule of law. By examining both contentious and advisory opinions of the Court, this research seeks to provide a clear answer to this fundamental question. The rule of law, as a mechanism to constrain arbitrary power by states, plays a crucial role in legal legitimacy. Through its decisions, the Court not only resolves disputes but also reinforces the rule of law by broadly interpreting and applying legal principles such as the right to self-determination, the right to life, the prohibition of indiscriminate attacks, the principle of distinction, and the prohibition of torture. These are considered substantive elements of the rule of law. In doing so, the Court significantly contributes to the establishment and legitimacy of the rule of law and advances the development of international law.