On the benefit of reinventing the wheel: the notion of single internationally wrongful act

This article is a critical reaction to the 2020 EJIL Foreword, titled ‘Guiding Principles on Shared Responsibility in International Law’. It focuses on Principle 3, concerning a ‘single internationally wrongful act’ and it is divided into its constitutive elements: the meaning of same conduct (Section 2), the attribution to multiple persons (Section 3), the breach of ob- ligations (Section 4), and the indivisible injury (Section 5). The main criticism is that the Guiding Principles make things more complex than they already are. The established prin- ciples of international responsibility provide simpler and more effective answers. This is par- ticularly the case for Principle 3, which concerns multiple responsibilities arising from the same conduct. There are two main elements through which the Guiding Principles on Shared Responsibility seeks to provide guidance in the case of a plurality of internationally respon- sible persons. First, they employ the comprehensive notion of internationally wrongful act, while ARSIWA and ARIO distinguish between the two elements of attribution of conduct and the breach of an obligation. Second, the Guiding Principles consider the injury to be a constitutive element included in the definition of shared responsibility, while ARSIWA and ARIO only employ it in the context of reparation and countermeasures. There are no actual benefits coming from these attempts of clarification.