The Practical Guide to Humanitarian Law

« Calling things by the wrong name adds to the affliction of the world. » Albert Camus.

Parties to the Conflict

So as to ensure the broadest possible application of international humanitarian law, the 1949 Geneva Conventions and their 1977 Additional Protocols use the neutral term parties to the conflict to refer to both State and non-state actors taking part in hostilities. This term replaces in modern legal vocabulary that of belligerent , which remains in common use to designate individuals, groups, or States engaged in an armed conflict. However, armed conflicts are not confined to confrontation between official armed forces of States that have recognized their mutual existence. In the case of non-international armed conflicts, one of the parties is a non-state armed group whose authority and existence may not be officially recognized, such as rebels or insurgents. The non-state nature of those actors prevents them from signing international conventions on humanitarian law, yet it is crucial that the implementation of humanitarian law not be delayed by debates over the legal status of belligerents.

This is why humanitarian law distinguishes between the status of “parties to the conflict” and that of “High Contracting Parties.” The latter refers to States that have ratified the Conventions and therefore are bound to respect them, even if they are not directly involved in an armed conflict. Besides, High Contracting Parties are always bound to the Conventions they have signed vis-à-vis an enemy that would not have not signed the Conventions. Both will be bound by those provisions that have gained customary status, that is, most of the rules of the Geneva Conventions (including Common Article 3). There is no reciprocity condition as far as respect of IHL is concerned. This is particularly illustrated by the fact that one of the parties cannot invoke the violation of a humanitarian rule by the other party to justify its own violations of IHL.

The concept of parties to the conflict defines those signatory and non-signatory States as well as non-state parties involved in the conflict.

To overcome the defects of direct application of the Conventions, humanitarian law provides a complementary contractual mechanism. Indeed, the Conventions set forth the provision that all parties to a conflict should endeavor to bring all or part of the Conventions into force, from the beginning of the conflict, by means of special agreements (GCI–IV Common Art. 3). This mechanism is also open to entities or States party to the conflict that have not or cannot ratify the conventions (GCIV Art. 2). Besides, the Geneva Conventions clearly state that the application of international humanitarian law does not affect the legal status of parties to the conflict (GCI–IV Common Art. 3, API Art. 4).

Special agreement

Today, those conventional limits are partially offset by the fact that many provisions of international humanitarian law have acquired a customary nature. In 2005, the ICRC published a study identifying customary rules of IHL that apply in international and non-international armed conflicts. This customary IHL is binding on all States, even those that have not signed the Conventions. It is also binding on non-state armed groups party to a conflict, that, per definition, cannot ratify the Conventions.

Non-state armed groups may indeed have the status of parties to non-international armed conflicts. Two cumulative conditions must be fulfilled. First, the group must be engaged in hostilities against a State or States or another armed group with a certain degree of intensity (relevant criteria as mentioned by case law include the number, duration, and intensity of individual confrontations; the type of weapons and other military equipment used; the number and caliber of munitions fired; the number of persons and types of forces partaking in the fighting; the number of casualties; the extent of material destruction, and the number of civilians fleeing combat zone; etc.). Second, the group itself must be sufficiently “organized” (factors to be taken into account include the existence of a command structure and disciplinary rules and mechanisms within the armed group; the existence of headquarters; the ability to procure, transport, and distribute arms; the group’s ability to plan, coordinate, and carry out military operations, including troop movements and logistics; its ability to negotiate and conclude agreements such as cease-fires or peace accords; etc.).

As Parties to the conflict, non-state armed groups are compelled to respect humanitarian law relating thereto, that is to say, Common Article 3 to the four Geneva Conventions and Additional Protocol II of 1977, if applicable, and the customary law provisions. If there is evidence that non-state armed groups are acting in fact on behalf of or under the control of a foreign State, the armed conflict will be internationalized.

International humanitarian lawNon-state armed groups

International military forces deployed under UN Security Council mandate may also under certain conditions be considered parties to the conflict. This is the case when they use force in an offensive way beyond mere self-defense (when they “directly participate in hostilities”) and when they support one of the parties to the conflict.


The humanitarian law rules applicable will depend on the international or non-international character of the conflict. The qualification is not at the discretion of the parties to the conflict. Humanitarian law sets out criteria for factual and objective qualification in order to avoid controversy. These criteria are interpreted and clarified by the recent jurisprudence of the International Criminal Tribunals.

International armed conflictNon-international armed conflict

In the case of non-international armed conflicts, a non-state armed group recognized as a party to the conflict is bound to respect humanitarian law. However, humanitarian law does not recognize to members of armed groups the right to use force and, hence, the status of “combatants” and the rights attached hereto, for example, prisoner-of-war status and immunity from prosecution for mere participation in hostilities. Where IHL is silent, members of non-state armed groups remain subject to their domestic law, which considers them as criminals and grants the right to use force only to the national army. This situation creates a legal asymmetry that breaks the principle of legal equality of parties to the conflict, normally provided for by IHL.

It is possible to solve this issue by signing a special agreement between the parties to the conflict, as suggested by Common Article 3 (see supra). The possibility of an ad hoc agreement agreed upon by the State party to the conflict can help to restore a balance between the application of the provisions provided for by humanitarian law and those provided for by domestic law in non-international armed conflicts. This possibility allows parties to the conflict to enforce some or all provisions of Additional Protocol II without entailing the legal recognition of the non-state party to the conflict. This is particularly important to overcome the fear that signing such an agreement will give legitimacy to the opposing party and to enable the State to sign an agreement with a group considered illegitimate with regard to domestic law.

The classic rules of reciprocity do not apply in the case of international humanitarian law.

The fact that a party to a conflict has not ratified or has failed to respect the Geneva Conventions does not free the other party from its obligation to respect humanitarian law (GCI–IV Common Arts. 1 and 2). This is particularly important in the case of non-international armed conflicts where there is a legal and practical asymmetry between parties to the conflict: on the one hand the State, and, on the other, individuals and non-state armed groups, which may be regarded as criminals in the eyes of domestic law.

BelligerentCiviliansCombatantsCustomary international lawHigh Contracting PartiesInternational armed conflictInternational conventionsLegal status of the parties to the conflictNon-international armed conflictNon-state armed groupsPeacekeepingPrivate military companiesRespect for international humanitarian lawSpecial agreement

For Additional Information: Kleffner, Jann. “The Applicability of International Humanitarian Law to Organized Armed Groups.” International Review of the Red Cross 882 (June 2011): 443–61.

Meyrowitz, H., M. Sassoli, and Y. Shany. “Should the Obligations of States and Armed Groups under International Humanitarian Law Really Be Equal?” International Review of the Red Cross 882 (June 2011): 425–36.

Perrin, Benjamin, ed. Modern Warfare: Armed Groups, Private Militaries, Humanitarian Organizations and the Law . Vancouver: UBC Press, 2012, part 1.

Pfanner, Tony. “Asymmetrical Warfare from the Perspective of Humanitarian Law and Humanitarian Action.” International Review of the Red Cross 857 (March 2005): 149–74.

Somer, Jonathan. “Jungle Justice: Passing Dentence on the Equality of Belligerents in Non-international Armed Conflict.” International Review of the Red Cross 867 (September 2007): 655–90.

Vité, Sylvain. “Typology of Armed Conflicts in International Humanitarian Law: Legal Concepts and Actual Situations.” International Review of the Red Cross 873 (March 2009): 69–94.

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