The EU and EURATOM are the only international organizations ever to have made a declaration entitled “reservation” when approving an international agreement. Though the ability of the EU to express its own consent also implies its ability to make reservations, the legal regime applicable to this new practice needs to be clarified. This article sets out the challenges presented when determining the customary international law rules on reservations applicable to the EU. In particular, uncertainty as to the relevant rules has led to an ambivalent reservations practice. The EU sometimes acts as a unidimensional entity and makes reservations or objections in order to express its own unilateral interests. However, it remains compelled by the multidimensional reality of its status as a regional integration organization. Reservations may thus be a tool to reconcile this reality and accommodate the regime of a multilateral agreement to the participation of an international organization. This article concludes that the EU’s practice provides useful insights into the development of reservations-making by international organizations and into their autonomous participation in international lawmaking more broadly.
Common Market Law Review