International Law of Regional Organisations

The Study Group seeks to explore the interactions between Regional International Organizations (RIOs) (including the European Union (EU)) and international law and, more specifically, the practice of international law by RIOs/EU within and outside the organization.

In recent years, RIOs, and most notably the EU, have not only grown in number and powers, but have also gained in influence internationally. On the one hand, they have had, through their own internal law or practice of international law, an increasing impact on their Member States’ practice of international law (e.g. in case of tension with those States’ other duties under general or special international law). On the other, some of them have also developed their own practice of international law: both inside their legal orders (in cases where their internal law may be described as such), when receiving or interpreting international law; and outside, when they interact with third States or other (universal or regional) IOs, and impact on international law-making.

Despite their increasing importance in international law, RIOs have rarely been discussed as an object of international legal study. When they have, it has been with respect to (usually economic) individual RIOs only (esp. the EU’s external relations), and almost never comparatively. The Study Group aims to remedy this gap and to provide a worldwide platform to address the multitude of questions that the interplay between RIOs/EU and international law gives rise to. It should also serve as a timely observatory of the increasing regionalization of international law, and its implications for the universal authority and coherence of international law.

The questions the Study Group seeks to address include, but are not limited to, the following: the status (validity/rank/direct effect) of international law in the RIO’s/EU’s legal order (provided the latter may be described as such and is distinct, or even autonomous, from international law), as well as the more indirect ways in which international law permeates the RIO’s/EU’s law (e.g. consistent interpretation); variations in the interactions between RIOs/EU and international law across regimes of international law; the reception and effects of RIO/EU law (qua IO or State law) in international law, and esp. The influence of the RIO’s/EU’s institutions’ interpretation of general international law on the latter; commonalities and differences between RIOs/EU in the way in which they organize their external relations.

PLEASE NOTE THAT RESEARCH AND CONTRIBUTIONS MADE BY THE STUDY GROUP MEMBERS IS AVAILABLE ONLINE here