Project Description

The Context

International society and the international legal order have gone through radical transformations in recent decades, notably in the multiplicity of actors operating in interaction with each other. In a substantial and increasing number of cases, injurious consequences do not result from individual acts by individual actors, but arise from concerted action by states, international organizations and other actors. This occurs for instance in the context of multinational military operations, extra-territorial migration policies, or acts that contribute to climate change and other transboundary environmental problems. The significance of this phenomenon is illustrated in the News section of the SHARES website, where news items relevant to shared responsibility are frequently posted. In all these situations, responsibility may be shared between two or more states and/or other actors.

While concerted action may further the delivery of international common goods, it may come with a downside, as it complicates the allocation of responsibility. Where common action fails to deliver its promises, and in particular when acts and omissions breach rights or obligations, the question of who is responsible will arise. Who, among the multiplicity of actors involved in cooperation, is to answer for the failure to live up to promises and abide by agreements, and who is to provide reparation to any injured parties? The international legal order increasingly has to come to grasps with a truth learned long ago in organization theory: as the responsibility for any given instance of conduct is scattered among more actors, the discrete responsibility of every individual actor diminishes proportionately.

The principles applicable to situations of shared responsibility are not well developed. The International Law Commission (ILC), both in its work on the responsibility of states and the responsibility of international organizations, recognised that attribution of acts to one state or organization does not exclude the possible attribution of the same act to another state or organization. However, the ILC has provided limited guidance to the allocation of responsibility or reparation in such cases. Indeed, the whole issue is undertheorised and underexplored.

The Objectives

As the variety and frequency of cooperative endeavors between states and other actors expand, international rules and processes must be developed to better allocate international responsibility between multiple actors. For this to be achieved, our fundamental understanding of the principles and processes at stake needs to be enhanced. The objective of the SHARES Project is therefore to increase the body of scientific knowledge on the topic, by developing a comprehensive study of theoretical and practical issues of shared responsibility. The project will propose not only a technical and procedural analysis of how to deal with shared responsibility, but will situate such an analysis in a novel rethinking of the nature of international responsibility.

The Output

Over the course of the project, the project team has provided regular output, engaging in academic debates on the topic of shared responsibility, while also aiming at addressing a larger public. This output consists of events (conferences, seminars, lectures, debates) and publications (articles, books, research papers, conference reports and blogposts).


Renowned scholars have been invited to give presentations on relevant subjects, dealing with issues of shared responsibility. More information can be found here.

SHARES Debates have been organised in collaboration with SPUI25, the academic and cultural centre of the University of Amsterdam. These debates are organised throughout the academic year to provide a platform for discussions with a broader (non-academic) audience on questions of shared responsibility.

In order to provide a better understanding of specific areas where issues of shared responsibility arise, a series of expert meetings with professionals and academics was organized at the beginning of the project. Reports of these seminars are available in the areas of international environmental law, refugee law and peace operations. Furthermore, other seminars, in particular related to the SHARES Book Series, have been organized in 2013/2014.

In November 2011, a Conference on the Foundations of Shared Responsibility in International Law was held. It explored fundamental and conceptual issues that explain the state of law, as well as possibilities for further development of the law pertaining to shared responsibility. This conference was also a first take on the findings of the project, and allowed for confrontation with competing and/or complementary approaches.

SHARES Publications

Research Papers
The findings of the project are made available in a Research Paper Series addressing a wide range of general or specific issues of shared responsibility. SHARES Research Papers are available here.

Key results of the project have been published in articles in leading international journals, including the European Journal of International Law, the Leiden Journal of International Law and the International Organizations Law Review. In addition, articles have been published in edited volumes that are not as such part of the project, but that substantively relate to the SHARES Project. Articles can be found here.

Collection of papers on Procedural Aspects of Shared Responsibility in International Adjudication 
Written in the context of our project, the following six articles have been published as part of the collection of papers on Procedural Aspects of Shared Responsibility in International Adjudication in (2013) 4(2) Journal of International Dispute Settlement 277-405.

  1. Procedural Aspects of Shared Responsibility in International Adjudication: Introduction – André Nollkaemper, see here.
  2. Procedural Aspects of Shared Responsibility in the International Court of Justice – Martins Paparinskis, see here.
  3. Procedural Issues Relating to Shared Responsibility in Arbitral Proceedings – Freya Baetens, see here.
  4. Procedural Aspects of Shared Responsibility in the WTO Dispute Settlement System – Lorand Bartels, see here.
  5. Procedural Aspects of Shared Responsibility in the European Court of Human Rights – Maarten den Heijer, see here.
  6. Shared Responsibility Aspects of the Dispute Settlement Procedures in the Law of the Sea Convention – Ilias Plakokefalos, see here.

Collection of articles on Organised Non-State Actors
Written in the context of our project, the following five articles have been published as part of the collection of articles on Organised Non-State Actors (edited by Jean d’Aspremont, André Nollkaemper, Ilias Plakokefalos and Cedric Ryngaert) in (2015) 62 Netherlands International Law Review 49-160. The collection was organised with support of SHARES, the Utrecht Centre for Accountability and Liability Law, and the Leuven Centre for Global Governance Studies. A SHARES/UU/KU Leuven Seminar on ‘Shared Responsibility and Organised Non-State Actors’ was held in Utrecht on 13 December 2013.

  1. Sharing Responsibility Between Non-State Actors and States in International Law: Introduction – Jean d’Aspremont, André Nollkaemper, Ilias Plakokefalos and Cedric Ryngaert, see here.
  2. Armed Opposition Groups and Shared Responsibility – Veronika Bílková, see here.
  3. Shared Responsibility and Multinational Enterprises – Markos Karavias, see here.
  4. Private Security Companies and Shared Responsibility: The Turn to Multistakeholder Standard-Setting and Monitoring through Self-Regulation-‘Plus’ – Sorcha MacLeod, see here.
  5. Shared Responsibility and Non-State Terrorist Actors – Kimberley N. Trapp, see here.

The SHARES Book Series, published by Cambridge University Press, consists of several edited volumes and monographs. The first three edited volumes are:

  1. Principles of Shared Responsibility in International Law (volume 1) examines the concepts and principles of the law of international responsibility though the new perspective of shared responsibility. This volume was published in 2014, see here.
  2. Distribution of Responsibilities in International Law (volume 2) discusses how responsibility is to be distributed among several wrongdoing actors in case nothing has been agreed ex ante. This volume was published in 2015.
  3. The Practice of Shared Responsibility in International Law (volume 3) will explore the practice of shared responsibility in international law. In this volume, relevant practices will be mapped in over forty different issue-areas.

Blog posts on topical issues of shared responsibility and current events are regularly published on the SHARES Blog by members of the research project as well as external contributors.

Other Publications
Other publications that are substantively related to SHARES, such as a book entitled Responsibility to Protect: From Principle to Practice, are also published in the framework of the Amsterdam Center for International Law (ACIL).