In This Article Expand or collapse the "in this article" section Armed Opposition Groups

  • Introduction
  • General Overviews
  • Historical Approaches
  • Current Approaches
  • Public International Law and Armed Opposition Groups
  • The Law of Non-International Armed Conflicts
  • Detention and Internment by Armed Opposition Groups
  • Participation in Lawmaking Processes

International Law Armed Opposition Groups
Ezequiel Heffes
  • LAST REVIEWED: 28 November 2016
  • LAST MODIFIED: 28 November 2016
  • DOI: 10.1093/obo/9780199796953-0143


Broadly, international law neither defines what “armed opposition groups” are nor includes the notion of these non-state actors as parties to an armed conflict. This is because these groups can take different forms and act in different situations. Some specific treaty provisions, however, do refer to certain conditions that should be fulfilled by an entity in order to be considered as an armed opposition group. Common Article 3 of the Geneva Conventions of 1949, for instance, implies the participation of at least one armed opposition group. Additionally, the International Criminal Tribunal for the former Yugoslavia (ICTY) has understood since the Tadić decision that these entities should have a minimum degree of organization, which has also been endorsed by the International Criminal Tribunal for Rwanda (ICTR) and the International Criminal Court (ICC). This is also in line with the requirements established by Article 1 of the 1977 Additional Protocol II regarding “organized armed groups,” although this treaty includes further conditions concerning its more restricted scope of application rather than intending to define armed opposition groups as a category. Several nongovernmental organizations and academic institutions have attempted to tackle this issue. The Institut de Droit International (Institute of International Law) in 1999, for example, affirmed that “non-State entities” as parties to non-international armed conflicts are those who oppose governmental forces or “are fighting entities of a similar nature and who fulfil the conditions set forth” in Common Article 3 or Article 1 of the Additional Protocol II. Yet the most comprehensive explanation is possibly the one provided by Nils Melzer in the Interpretative Guidance on the Notion of Direct Participation in Hostilities under International Humanitarian Law (Melzer 2009, cited under Current Approaches): “[o]rganized armed groups belonging to a non-State party to an armed conflict include both dissident armed forces and other organized armed groups. Dissident armed forces essentially constitute part of a State’s armed forces that have turned against the government.” Certainly, there are other terms besides “armed opposition groups” also used to refer to these actors, sometimes depending on the applicable rules, such as the term “organized armed groups” under the 1977 Additional Protocol II, but mostly on the features that wish to be stressed. The essential differences can be found in certain characteristics: (1) “armed opposition groups” are by nature illegal according to states’ domestic laws; (2) in cases of internal armed conflicts, they are not members of any governmental armed forces; and (3) they are mainly created to “make war,” therefore their only way of doing it is through the use of armed violence. Within these characteristics, however, it is still possible to find a wide variety of actors in terms of size, command and control capabilities, modus operandi, control of territory, aims, and so on, which recognizes a margin of uncertainty. The temporal scope of application in non-international armed conflicts seems to be crucial, since the mere notion of “armed opposition group” is based on the existence of hostilities. Unlike governments, which are supposed to persist through time, they no longer exist after the end of an armed conflict, whether because they triumph in their struggle, eliminating the need to fight, or they are defeated and disbanded.

General Overviews

Armed opposition groups have spawned a vast literature both in political science and international law. A number of works and judicial decisions deal with their different aspects. Most of them, however, usually refer to the law of non-international armed conflicts. This means that in order to define what an armed opposition group is, one should refer to its international obligations. Nowadays, these entities are not only discussed from an international humanitarian law perspective, but also from the perspective of international human rights law, use of force in international law, international responsibility, and international refugee law. Daboné 2012 (cited under Public International Law and Armed Opposition Groups) examines the place that armed opposition groups occupy in public international law and provides an insightful guide to studying the general behavior of these non-state entities. Sivakumaran 2012 (cited under the Law of Non-International Armed Conflicts) offers a useful and complete bibliography and points out current views and practices of both governments and armed opposition groups. Sivakumaran 2012 suggests that only through their participation, the applicable law “can become truly fit for purpose.” In twelve chapters he deals with almost every possible issue from an international humanitarian law perspective. Moir 2002 also studies the law of non-international armed conflicts by examining the scope of the applicable law, while Zegveld 2002 examines the accountability for the acts committed by armed opposition groups from three different perspectives: individual responsibility, responsibility of the group as such, and responsibility of the state for the acts of armed opposition groups. The subject of the responsibility of “armed opposition groups” has also been explored by d’Aspremont 2009, Dudai 2011, Cahin 2010, Heffes 2013, and Gal-Or, et al. 2015 (cited under International Responsibility of Armed Opposition Groups as Such), whose entire Part Three is dedicated to the international responsibility of these entities.

  • Cahin, Gerard. “Attribution of Conduct to the State: Insurrectional Movements.” In The Law of International Responsibility. Oxford Commentaries on International Law. Edited by James Crawford, Alain Pellet and Simon Olleson, 247–256. Oxford, UK: Oxford University Press, 2010.

    Examines the rules on attribution to States of those acts of successful and unsuccessful insurrectional movements.

  • d’Aspremont, Jean. “Rebellion and State Responsibility: Wrongdoing by Democratically Elected Insurgents.” International and Comparative Law Quarterly 58.2 (2009): 427–442.

    DOI: 10.1017/S0020589309001006

    Suggests that the application of Article 10 of the Articles on Responsibility of States for Internationally Wrongful Acts is problematic with respect to former insurgents that become to the power through democratic elections.

  • Dudai, Ron. “Closing the Gap: Symbolic Reparations and Armed Groups.” International Review of the Red Cross 883 (2011): 783–808.

    DOI: 10.1017/S1816383112000082

    Focuses on symbolic reparations given by armed opposition groups, such as acknowledgement of the truth and apologies. The main case study is the Irish Republican Army. Concludes that in some circumstances armed opposition groups have the capacity and willingness to provide some measures of remedy to victims.

  • Heffes, Ezequiel. “The Responsibility of Armed Opposition Groups for Violations of International Humanitarian Law: Challenging the State-Centric System of International Law.” Journal of International Humanitarian Legal Studies 4 (2013): 81–107.

    DOI: 10.1163/18781527-00401003

    Explores the possible application of the Articles on Responsibility of States for Internationally Wrongful Acts to wrongful acts committed by members of an armed opposition group so as to attribute them to this entity as such.

  • International Court of Justice. “Case concerning Military and Paramilitary Activities in and against Nicaragua (Nicaragua v. United States of America). Merits: Judgment of 27 June 1986.” ICJ Reports (1986): 14–150.

    Holds that an “effective control” is needed in order to determine whether certain acts of an armed opposition group (contras) could be attributed to the United States. Concluded that the state did not exercise such control and therefore no state responsibility was found.

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

    DOI: 10.1017/CBO9780511495168

    Examines the existing law of non-international armed conflicts. It traces the development of international law from the 19th century by analyzing the categories of armed opposition groups in terms of rebellion, insurgency, and belligerency. It then goes through their current regulation, particularly with respect to international humanitarian law.

  • Zegveld, Liesbeth. The Accountability of Armed Opposition Groups in International Law. Cambridge, UK: Cambridge University Press, 2002.

    DOI: 10.1017/CBO9780511495199

    The most comprehensive analysis on the responsibility of armed opposition groups. Analyzes the responsibility of the groups as such, of their leaders, and also of states for acts of these non-state entities.

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