Skip to main content

Shared Responsibility in International Law

Final Report Summary - SHARES (Shared Responsibility in International Law)

Questions of shared responsibility are critical to many pressing issues in international law. As states, international institutions, and other actors increasingly engage in cooperative action, the likelihood of harm or other outcomes proscribed by international law multiplies. Injured parties may then be faced with a plurality of wrongdoing actors. The principles of international law on the basis of which responsibility among multiple actors is currently allocated may be of help, but do not always provide clear answers. A comprehensive conceptual framework which would allow us better to understand the phenomenon of shared responsibility still requires formulation.

The SHARES project has addressed the fundamental questions for positive law and legal doctrine that are raised by this emerging practice of harm caused by multiple parties. It has provided new perspectives that allow us to understand how the international legal order does and could address shared responsibility. Such new perspectives serve both the interests of injured parties, who may otherwise experience difficulty in identifying the responsible entities and the scope of their responsibility, as well as the interests of states more generally by providing some predictability as to how their own responsibility might be engaged.

The SHARES project made a range of findings that help us better understand questions of shared responsibility and to that allows us to work towards improvements. These findings include the following. First, there is not a one size fits all approach: allocation of responsibility in regard of climate change differs from that in relation to refugee law, and the nature and form of shared responsibility differs, depending on the nature of the issue-area, the nature of the norms breached and the interests protected. Second, in certain conditions, existing international law allows for a dual, or parallel attribution of conduct to two or more authors of an internationally wrongful act. This was for instance important in relation to the responsibility of both the United Nations and the Netherlands in relation to the genocide in Srebrenica. Third, in many areas of international law, such as refugee law, the general law of responsibility may not have much to offer, but specific rights and obligations that have been laid down by states in the relevant treaties, can accommodate questions of shared responsibility (which does not mean that they always do).

Fourth, when questions of shared responsibility arise in international adjudication, the procedural law of the relevant international courts and tribunals is critical for the eventual determination of questions of shared responsibility. For instance, can international courts determine responsibility of one actor when a co-responsible actor is not involved in the procedure? Such procedural law may fulfill different functions in relation to the substantive law of shared responsibility: whereas sometimes these functions facilitate the determination of shared responsibility, in other cases they serve competing interests.

The SHARES project has launched a book series. Six core volumes are envisaged. These examine 1) the principles of shared responsibility, 2) distribution of shared responsibilities, 3) the practice of shared responsibility, consisting of over 40 issue-areas, 4) causation in the law of responsibility, 5) a new theory of shared responsibility, and 6) procedural aspects of shared responsibility in international adjudication.

The SHARES project also has undertaken a wide variety of activities to transmit the outcomes of its work to interested stakeholders and the wider public. These activities include SHARES Lectures, SHARES Debates on questions of sustainable development and refugee law, SHARES Blog posts and a SHARES website ( which collects and provides access to a wealth of researches, information and views on questions of shared responsibility.