Ex aequo et bono originates from the concept of “fundamental fairness.” Translated from Latin, the phrase means “what is fair and good,” allowing decisions to reflect justice even outside formal legal constraints. According to Black’s Law Dictionary, the term ex aequo et bono is defined as “according to what is equitable and good,” referring to a decision-maker, especially in international law, who is authorized to decide ex aequo et bono and is not bound by legal rules but may instead follow equitable principles. Article 38(2) of the ICJ Statute allows the Court to “decide a case ex aequo et bono if the parties agree thereto,” providing an exception to Article 38(1), which mandates the Court to decide disputes submitted to it “in accordance with international law.” Notably, the power to decide ex aequo et bono has never been exercised and is challenging to reconcile with the ICJ’s judicial nature (Crawford, p. 728). This raises the question: What are the key differences between ex aequo et bono and equity? Why do parties avoid the justice route, and what purpose could it serve despite its infrequent use?
Ex Aequo et Bono and Equity
The decision of a case ex aequo et bono must be distinguished from cases where the Court applies the general principles of law recognized by States, or the equitable principles of international law, or interprets existing law in an equitable manner (equity infra legem). In such cases, the Court is bound to keep within the limits of the existing law, whereas in the case of an exercise of its ex aequo et bono power with the consent of the parties, the Court is not required to have strict regard to existing rules of law, and may even disregard them altogether. The power of decision ex aequo et bono involves elements of compromise and conciliation, whereas equity infra legem finds application as part of the normal judicial function (Crawford, p. 45).
In Free Zones, the Permanent Court of International Justice (PCIJ) was tasked with resolving issues under a Treaty of Versailles provision, with Switzerland insisting on a decision based on existing rights rather than considerations of pure fairness (ex aequo et bono). The Court, by a narrow majority, agreed, emphasizing that any authority to decide ex aequo et bono would require explicit and exceptional authorization, which was absent in the agreement. The case highlights the distinction between equity, which applies fairness within the law, and ex aequo et bono, which allows decisions purely on fairness, bypassing legal rights, a power the Court deemed exceptional and conditional on clear consent by the parties. In the North Sea Continental Shelf, the ICJ rejected the equidistance method advocated by Denmark and the Netherlands as obligatory, instead basing its decision on equitable principles (infra legem), which operate within the framework of law and relevant circumstances. It emphasized that equitable principles derive justification from legal rules, unlike ex aequo et bono, which involves deciding based on fairness outside the legal framework and requires explicit party consent under Article 38(2) of the ICJ Statute. Additionally, as asserted by the late Justice Lauterpacht that adjudication ex aequo et bono creates new relations between parties, emphasized that it “differs clearly from the application of the rules of equity” and constitutes a fundamental part “of international law, as indeed, of any legal system.”
Strategic Avoidance by States and Purpose
The reluctance to use ex aequo et bono or the justice route stems from states’ strategic considerations. Opting for ex aequo et bono can signal a weak legal position, potentially undermining a party’s credibility in negotiations. This perception may prompt opponents to adopt more aggressive stances, leading to out-of-court settlements rather than ICJ adjudication. States also gain reputational benefits by adhering to the law route. Aligning with established legal norms showcases a commitment to the international legal order, enhancing a state’s reliability as a treaty partner. In contrast, ex aequo et bono lacks the legitimacy associated with formal legal judgments, risking the ICJ’s perception as a neutral arbiter.
Despite its disuse, the justice route serves a strategic role. It acts as a signaling mechanism, enabling parties to reveal weaknesses in their legal arguments and encouraging negotiated settlements. This reduces the ICJ’s caseload, allowing it to focus on disputes requiring definitive legal adjudication. Moreover, its mere existence reinforces the legitimacy of legal norms by positioning the law route as the more rigorous option.
Additionally, ex aequo et bono could be gap-filling in the sense that it aims to achieve fairness between parties. Like gap-filling under equity law, it empowers adjudicators to exercise discretion in cases where the law is silent or unclear, or where applying the law would lead to an inequitable outcome. The key distinction lies in the source and scope of the adjudicator’s discretion. Gap-filling under equity law operates within the confines of existing legal frameworks, allowing adjudicators to interpret and apply legal principles to achieve just outcomes. In contrast, ex aequo et bono grants adjudicators the authority to decide disputes based on fairness and good conscience, potentially extending beyond the strict boundaries of the law. This means that while equity-based gap-filling remains tethered to legal norms, ex aequo et bono decisions may incorporate broader considerations of justice and fairness, even if they do not align with established legal rules.
In conclusion, ex aequo et bono provides a fairness-based approach to justice but is rarely used due to strategic concerns and potential risks to credibility. Yet, its availability underscores that balancing fairness and legality remains central to the ICJ.
Author
Pham Quoc Hao is a junior specializing in International Law at the Diplomatic Academy of Viet Nam and the co-founder of Vietnam’s first student-led international law blog, https://www.juris-exploratores.org. His interests include general international law, the law of the sea, and international environmental law.
