International Law Noninternational Armed Conflict (“Civil War”)
Faustin Ntoubandi
  • LAST REVIEWED: 22 April 2020
  • LAST MODIFIED: 22 April 2020
  • DOI: 10.1093/obo/9780199796953-0206


A noninternational armed conflict (NIAC) or civil war—as it used to be called in the past—is an armed conflict that occurs within the territory of a particular state, between government armed forces and organized armed groups, or between such groups fighting each other. It is also often called “internal armed conflict,” as opposed to an international armed conflict involving at least two states. NIACs constitute the oldest form of armed conflicts and have become, since the end of the Cold War, more pervasive and more lethal than international armed conflicts. Conflicts since the late 20th century in Cambodia, the former Yugoslavia, and Rwanda, as well as the ongoing ones in the Democratic Republic of the Congo, Libya, Yemen, Ukraine, and Syria, are just a few illustrations of the pervasive character of NIACs. International law has, for a long period of time, considered NIAC as a purely intrastate matter despite its external reverberations. However, this stance has evolved following the adoption of the four Geneva Conventions in 1949. The latter codify a corpus of customary rules, commonly known as jus in bello, which regulate the conduct of hostilities in the context of armed conflict by restraining the use by the warring parties of certain means and methods of warfare. Article 3 of each of the four Geneva Conventions introduces NIAC as “armed conflict not of an international character,” the victims of which must be subjected to the minimum standards of protection. In 1977 the Geneva Conventions of 1949 were supplemented by two protocols, which operate a clear distinction between international armed conflict (Additional Protocol I) and NIAC (Additional Protocol II or AP II). AP II defines humanitarian law rules that govern hostilities in internal conflicts. Such rules, together with other relevant treaty provisions and humanitarian principles, constitute the corpus of the jus in bello regulating the conduct of NIACs. A number of internal conflicts that erupted in various countries in the beginning of the 1990s have given ad hoc international tribunals, especially the 1993 International Criminal Tribunal for the Former Yugoslavia (ICTY) and the 1994 International Criminal Tribunal for Rwanda (ICTR), the opportunity not only to outline the nature and delimit the frontiers of NIACs, but also to set the conditions under which individual criminal liability may arise as a result of the crimes committed in the context of such conflicts.

General Overviews

Unlike many concepts relating to the jus in bello, there is no general definition of NIAC in public international law. Owing to this omission, the question of the existence or not of a NIAC has become central for the determination of the law applicable in the context of an armed conflict taking place within the borders of a state. Common Article 3 to the four Geneva Conventions of 1949 was the first provision to specifically envisage humanitarian protection in situations of internal armed conflicts. However, its provisions are cast in general terms and do not provide a definition of a NIAC capable of triggering its application. Although many authors consider this omission as positive in that it allows the provision a maximum width for the operation of humanitarian norms, thus lowering its threshold of application, it nevertheless left a number of fundamental questions unaddressed. These include the distinction between NIACs and other types of conflicts, the identity and organization of the parties to the conflict, the required threshold of violence, and the legal consequences of an illegal conduct committed in the conflict. Subsequent instruments have tried to remedy this situation. Thus, Additional Protocol (AP) II sets a range of requirements for the existence of, and the determination of, the parties to a NIAC. In addition, Article 8(2) of the 1998 Statute of the International Criminal Court (ICC Statute) provides for individual criminal responsibility for war crimes committed during a NIAC. Increasingly, some internal armed conflicts tend to internationalize themselves due to the implication of foreign parties. It is the case of national liberation wars [Articles 1(4) and 96 (3) of Additional Protocol I of 1977] and the War on Terror (US military operations against the Taliban in Afghanistan or the International Coalition’s military action against ISIS in Syria since 1991). Various texts address all or some of the issues pertaining to NIACs. The relevant basic texts include Bothe, et al. 1982, which provides a general overview of the law of armed conflicts followed by a detailed commentary of the provisions both of AP I and AP II. However, Cullen 2010 produces the most comprehensive definition of NIAC, whereas Dinstein 2014 addresses various aspects of the international regulation of NIACs. The protection of civilians in the context of internal conflicts is offered in Moir 2002.

  • Bothe, Michael, Karl J. Partsch, and Waldemar A. Solf, eds. New Rules for Victims of Armed Conflicts: Commentary on the Two 1977 Protocols Additional to the Geneva Conventions of 1949. The Hague: Martinus Nijhoff, 1982.

    These authors were involved in the negotiation of APs I and II. In this book, they give a firsthand account of the meaning of the two texts, through a commentary, article by article, of the provisions of the Protocols. The book also reveals the intent of the negotiators as expressed during the travaux préparatoires. This volume is an important tool for a better understanding and implementation of these treaties.

  • Cullen, Anthony. The Concept of Non-international Armed Conflict in International Law. Cambridge, UK: Cambridge University Press, 2010.

    DOI: 10.1017/CBO9780511712111

    Adding clarity to the origin and meaning of the concept of NIAC in international humanitarian law, this book develops arguments that refine the interpretation of the lower threshold of NIAC established by Common Article 3 to the 1949 Geneva Conventions.

  • Dinstein, Yoram. Non-international Armed Conflicts in International Law. Cambridge, UK: Cambridge University Press, 2014.

    DOI: 10.1017/CBO9781107279391

    Analyzes the legal implications of NIACs by exploring, among other aspects, the rules regulating the conduct of internal conflicts, state responsibility for wrongdoing, and the relationship between human rights and war crimes. Provides a comprehensive treatment of the fundamental legal issues arising out of the application of international law to internal armed conflicts.

  • Moir, Lindsay, The Law of Internal Armed Conflict. Cambridge, UK: Cambridge University Press, 2002.

    DOI: 10.1017/CBO9780511495168

    In this book, Moir engages in an in-depth analysis of international law rules that protect civilians in internal armed conflicts. The author gives an account of the historical development of the applicable law and assesses its effectiveness in actually protecting the victims of internal armed conflicts.

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