NATO and International Law in Transition: Institutional Evolution, Collective Self-Defense, and the War in Ukraine

NATO and International Institutional Law

By Anne Verhelst

Intersentia, 2025, 1^st ed., 222 pages, €140.00, ISBN: 9781839705502

Collective Self-Defence in International Law

By James A. Green

Cambridge University Press, 2024, 386 pages, US$142.00 ISBN: 9781009406383

NATO and the War in Ukraine: Geopolitical Context and Long-term Consequences

By Jan Eichler

Springer Nature Switzerland AG, 2024, 186 pages, €129.99, ISBN: 9783031687785

Introduction

Established by the North Atlantic Treaty in 1949, the North Atlantic Treaty Organization (NATO) subsequently evolved into an institutionalized security organization with international legal personality, a status formally recognized through the 1951 Ottawa Agreement.¹ From its original twelve founding members, NATO admitted only four additional members—Greece and Türkiye in 1952, West Germany in 1955, and Spain in 1982—over the course of the Cold War, bringing the Alliance’s membership to sixteen by the end of the bipolar era. The post-Cold War era, however, witnessed an unprecedented enlargement process, during which sixteen additional states joined the Alliance between 1999 and 2024. Today, NATO comprises thirty-two members and represents nearly one billion people across Europe and North America.²