Contemporary armed conflicts have become ever more protracted, complex and urbanised, with far-reaching humanitarian and socio-economic consequences, such as severe damage to infrastructure, disruption of services, and protracted displacement. As a result of the changing dynamics of contemporary armed conflicts, the applicable law, the required legal and institutional responses, and the surrounding legal issues become more intricate as well. Our research in this area aims to assess the evolution of international humanitarian law in the context of the 21st century warfare, multinational military operations and cross-border law enforcement; examine the interactions between various legal regimes applicable to armed conflicts; and contribute to the development of urgently needed legal responses to address forced displacement and facilitate humanitarian assistance.

The law of the use of force and self-defence continues to be a source of divergence and contestation in the practice of states and scholarly approaches. Our research in this area aims to take stock of the evolution of jus ad bellum in a shifting world order with the rise of non-state actors, spread of terrorism, and the challenges of increasing unilateralism in international affairs. More broadly, we also explore issues of collective security, sanctions and peacekeeping.



Highlights from our work in this area:

The Legal Pluriverse Surrounding Multinational Military Operations

The ‘Legal Pluriverse’ Surrounding Multinational Military Operations conceptualizes and examines the “Pluriverse”: the multiplicity of rules that apply to and regulate contemporary multinational missions, and the array of actors involved. These operations are further complicated by changes to the classification of the conflict, and the asymmetry of obligations on participants.

Structured into five parts, this work seeks, through the diversity of its authorship, to set out the web of legal regimes applicable to military operations including forces from more than one state. It maps out the ways in which different regimes interact, beginning with the laws of armed conflict and their relation to international humanitarian and human rights norms, and extending through to areas like law of the sea and environmental law.

A variety of contributors systematically compile and take stock of the various legal regimes that make up the pluriverse, assessing how these rules interact, exposing norm conflicts, areas of legal uncertainty, or protective loopholes. In this way, they identify and evaluate approaches to better streamline the different applicable legal frameworks with a view to enhancing cooperation and thereby ensuring the long-term success of multinational military operations.


Publisher: Oxford University Press

Published: 13 January 2020

ISBN: 9780198842965

Humanizing the Laws of War: The Red Cross and the Development of International Humanitarian Law

Over the past 150 years, the International Committee of the Red Cross (ICRC) has been one of the main drivers of progressive development in international humanitarian law, whilst assuming various roles in the humanization of the laws of war. With select contributions from international experts, this book critically assesses the ICRC’s unique influence in international norm creation. It provides a detailed analysis of the workings of the International Red Cross, Red Crescent Movement and ICRC by addressing the milestone achievements as well as the failures, shortcomings and controversies over time. Crucially, the contributions highlight the lessons to be learnt for future challenges in the development of international humanitarian law. This book will be of particular interest to scholars and students of international law, but also to practitioners working in the field of international humanitarian law at both governmental and non-governmental organizations.


Editors: Robin Geiß, Andreas Zimmermann, Stefanie Haumer

Publisher: Cambridge University Press

Publication date: 2017

ISBN: 9781107171350

ILA Study Group Final Report: The Conduct of Hostilities Under International Humanitarian Law - Challenges Of 21st Century Warfare

The final report of the ILA Study Group on the Conduct of Hostilities Under International Humanitarian Law – Challenges Of 21st Century Warfare, where Professor Robin Geiß served as Rapporteur from 2011-2017, addresses the extent to which the rules governing the conduct of hostilities need to be clarified, both in terms of their scope of application and their substantive aspects, given the changing dynamics of contemporary armed conflicts. The Report focuses particularly on the relationship of International Humanitarian Law (IHL) and International Human Rights Law in the conduct of military operations, technological challenges posed by new weapons systems and the function of the basic principles of IHL in the conduct of hostilities.


The full text of the report is available here.

International Humanitarian Law: A Comprehensive Introduction

Authored by our staff member Professor Nils Melzer, “International Humanitarian Law: A Comprehensive Introduction” is an introductory handbook that aims to promote and strengthen knowledge of international humanitarian law (IHL) among academics, weapon-bearers, humanitarian workers and media professionals. It presents contemporary issues related to IHL in an accessible and practical style, and in line with the ICRC’s reading of the law. That, plus its distinctive format – combining “In a nutshell”, “To go further” and thematic textboxes – make it the ideal everyday companion for anyone approaching IHL for the first time and curious about conflict-related matters, as well as for military and humanitarian personnel seeking useful guidance on a vast array of topics.


Publisher: International Committee of the Red Cross

Publication date: 2016

ISBN 9782940396467