TRICI-Law

The TRICI-Law project (‘The Rules of Interpretation of Customary International Law’) is a 5-year Starting Grant project of the European Research Council. The project aimed to show that customary international law, like treaty rules, is open to interpretation. It also sought to show that the interpretation process of customary international law (which is an unwritten source of law) follows certain rules that can be derived from the jurisprudence of international courts and tribunals.

Customary international law (CIL), along with treaties, is the most commonly used rule in international law. While the rules of interpretation of treaties are set forth in Articles 31-33 of the Vienna Convention on the Law of Treaties (VCLT), the rules of interpretation of customary international law have not been critically studied. This gap widens when we consider that interpretation plays a key role in any litigation and that one of the basic features of the effectiveness of a legal system is its predictability. If we do not know the rules of interpretation of the CIL, we are playing a "game" whose rules we do not know, thus predictability is far from guaranteed.

Therefore, the purpose of this project was to establish the existence of interpretive rules of customary international law and to investigate their content. The results affect the study and theory of CIL, clarifying the foundations of the international legal system, reducing normative conflicts and providing greater legal certainty and predictability in all interactions related to international law.

Duration of the project

2018 - 2023

Awarded grant

1,500,000 euros, obtained from European Research Council Starting Grant

Contact person at our Faculty

Prof. P. (Panos) Merkouris

Websites with additional information