Dr. Nathan Derejko publishes new book on Non-International Armed Conflict

Dr. Nathan Derejko, Mauro Chair in Human Rights and Social Justice and Assistant Professor at the University of Manitoba Faculty of Law, has published his first book on Identifying Non-International Armed Conflict: International Law and Practice with Cambridge University Press (2026).

Highly relevant to current world events, the book offers a critical and comprehensive examination of the concept of Non-International Armed Conflict (NIAC), including its normative and legal foundations, threshold of activation, and corresponding personal, geographical, and temporal scope of applicability under International Humanitarian Law. In other words, the factual and legal conditions that transform a situation of armed violence into one of armed conflict, thereby activating International Humanitarian Law.

This legal shift from armed violence to armed conflict holds profound implications for the application and interpretation of human rights law, as international humanitarian law permits, or at least tolerates, detention without charge and killing without warning. Current situations that are on the precipice of NIAC, but defy international consensus include the increasingly violent armed confrontations between security forces and criminal organizations in Brazil or between competing drug cartels in Mexico, or even so-called ‘robust’ United Nations peacekeeping operations. Most recently,  President Donald Trump asserted that the United States’ strikes against “drug cartels” in the Caribbean were lawful under international law because the USA was involved in a “Non-International Armed Conflict” against these drug cartels. This new book "makes such declarations less easy to sustain in law”, Derejko explains. 

Prior to joining the Faculty of Law at the University of Manitoba in 2022, Derejko was Director of the Human Rights Centre Clinic at the University of Essex, and Director of the Masters in Human Rights programme at University College London.  Derejko holds a PhD in International Human Rights and Humanitarian Law from the University of Essex in the United Kingdom, an LLM in International Human Rights Law from the National University of Ireland Galway, and a BA in Political Science from Dalhousie University, Canada.

His research and teaching interests span the interrelated fields of international human rights law, international humanitarian law, and collective security and the use of force. This book is a culmination of his particular research interest in the applicability and application of human rights during armed conflict, counter-terrorism and human rights, and the law and practice of non-international armed conflict. Over a decade in the making, the book arose out of his doctoral dissertation and grew from there spanning “five universities, five countries, seven academic positions, two kids, and one global pandemic […]. The bulk of the new research and writing – over 100 thousand words - occur[ed] in my new academic home here in the Faculty of Law at the University of Manitoba,” he said. 

Before departing on a book tour that will take him across Europe and Canada and engage like-minded scholars in several symposia, Derejko took some time to discuss his inspiration for writing this book and the research gaps he hopes it fills.

What was the impetus for writing this book?

The book originated as research I was doing on the use of force and the right to life in the context of the so‑called “global war on terror.” It soon became apparent to me that the foundational question, the proverbial elephant in the room, was whether the “global war on terror” constituted an armed conflict as a matter of international humanitarian law (IHL), and if so, which type of armed conflict it was.

This question was fundamental because, if the global war on terror was not legally an armed conflict, then any use of force would be governed exclusively by the default regime of international human rights law (IHRL). While both IHRL and IHL regulate the use of force against individuals, IHL permits, or at least tolerates, conduct that would otherwise be prohibited under IHRL. In short, the legality of detention without charge or the use of lethal force without warning turned on whether an armed conflict existed in the first place.

What gaps in this area of research does this book address?

The uncertainties surrounding the concept and contours of non‑international armed conflict were thrust to the forefront of international concern and adjudication during the global war on terror. While case law has brought a measure of clarity, almost every aspect of the concept of NIAC remains marked by a lack of conventional clarity and state consensus.

The book identifies, unpacks, and critically examines a range of complex and contested issues, engaging with the diverse positions advanced by states, international organizations, armed groups, and scholars. These include whether NIACs are necessarily internal armed conflicts or may occur across the territory of two or more states; the degree of organizational or operational nexus required between multiple armed groups for them to be considered a single party to a NIAC; and if, and under what conditions, United Nations peacekeepers, drug cartels, or rebel coalitions can become parties to a NIAC. The book further explores the concepts of “belonging” and “supporting” a party to a NIAC; the applicability of IHL to non‑opposing forces; the definition of “civilian” in NIAC; the determination and scope of membership in organized armed groups; and the legal viability of claims regarding a “global battlefield” or a “forever war.”

What audience can benefit from this book?

This book is not intended as an introductory text on non‑international armed conflict or international humanitarian law. Rather, it engages directly with advanced and unresolved questions in the field.

Its intended audience includes: academic audiences (legal and critical‑legal scholars and advanced students of international humanitarian law, international human rights law, international criminal law, and collective security and the use of force); states and government agencies engaged in national security, counter‑terrorism, and national defence policy (including members of legislative and judicial bodies, law enforcement agencies, and the armed forces); practitioners working in national and international organizations concerned with the law of armed conflict, the promotion and protection of human rights, international criminal accountability, international peace and security, and transitional justice.

What further research is needed to address remaining gaps in this area?

As means and methods of warfare continue to evolve, new factual scenarios and legal questions inevitably emerge. Key areas for further research include self‑defence against non‑state actors; the targeting of extra‑territorial military objectives; the human rights obligations of rebel groups; the operation of rebel courts and issues of complementarity before the International Criminal Court; the duty to surrender in non‑international armed conflict; and the contemporary role and relevance of the traditional law of neutrality in globalized non-international armed conflicts.