The Evolution of the Understanding of Reservations in the Scholarship and Practice of Contemporary International Law

Abstract

The article provides a comprehensive analysis of the evolution of the understanding of reservations in the scholarship and practice of contemporary international law as a special legal mechanism that ensures a balance between the universality of States’ participation in multilateral international treaties and the need to preserve their object and purpose. It is demonstrated that the institution of reservations emerged in response to the growing complexity of international relations, the expansion of treaty regulation, and the increasing need to involve as many States as possible in treaty regimes. The genesis of doctrinal approaches to defining the concept of a “reservation” is traced from early scholarly concepts of the first half of the twentieth century to its codified formulation in the 1969 Vienna Convention on the Law of Treaties and its further elaboration, in particular in the 2011 Guide to Practice of the United Nations International Law Commission. It is substantiated that, despite the diversity of doctrinal formulations, the key features of a reservation remain its unilateral character, its purpose of excluding or modifying the legal effect of certain treaty provisions in their application to the State that formulated it, as well as its connection with the procedure for expressing consent to be bound by a treaty. Particular attention is paid to the transformation of approaches to the permissibility of reservations: from the principle of unanimous consent, characteristic of the practice of the League of Nations period, to the criterion of compatibility of a reservation with the object and purpose of the treaty, formulated in the 1951 Advisory Opinion of the International Court of Justice on Reservations to the Genocide Convention and enshrined in Article 19 of the 1969 Vienna Convention. The significance of this transition for the development of modern treaty law is revealed; the main types of reservations are analyzed, including restrictive reservations, territorial reservations, and reservations concerning non-recognition, and the problems of distinguishing them from interpretative declarations are highlighted. It is established that the criterion for such differentiation is not the formal title of a unilateral statement, but its legal effect. The legal consequences of valid and invalid reservations, the particularities of their application in the field of international human rights protection, and the specifics of the participation of international organizations in the relevant treaty regimes are examined. It is concluded that the contemporary understanding of reservations is based on a combination of the principle of the sovereign consent of States with the requirements of the integrity of an international treaty, while the further development of this issue is associated with clarifying the consequences of impermissible reservations and analyzing recent international practice.