When Do Terrorist Organisations Qualify as "Parties to an Armed Conflict" Under International Humanitarian Law?

International humanitarian law (IHL), also known as jus in bello or the law of armed conflict, applies during international or non-international armed conflict, and during such conflicts, it places certain obligations on, or gives rights to, "parties to the conflict". During international armed conflicts, for example, persons protected under the Fourth Geneva Convention of 1949 are defined as civilians "who, at a given moment and in any manner whatsoever, find themselves, in case of a conflict or occupation, in the hands of a Party to the conflict or Occupying Power of which they are not nationals", while those protected under the Third Geneva Convention, namely prisoners of war, have to be "[m]embers of the armed forces of a Party to the conflict" or of militia or volunteer corps "forming part of such armed forces [or] belonging to a Party to the conflict". It is further specified that the application of the 1949 Geneva Conventions and Additional Protocol I "shall not affect the legal status of the Parties to the conflict". In times of non-international armed conflict, "each Party to the conflict shall be bound to apply" the minimum rules contained in Article 3, common to the Geneva Conventions of 1949 (Common Article 3). In total, 194 provisions of the Geneva Conventions and their Additional Protocols refer to party or parties to the conflict. In fact, more than half of the provisions of Additional Protocol I contain such wording.
Clearly, it is important to know therefore who can be regarded as a party to an armed conflict and when an entity becomes such a party. However, none of the relevant treaties contains a definition of the term, or any guidance as to what has to be understood as the concept "party to an armed conflict". The present contribution aims to shed some light on this notion. It is important to provide such clarification, because some States have a tendency to reject the idea that terrorist organisations or groups can be a party to an armed conflict and as such be subject to, but also benefit from, the rules of IHL. Yet, one must be mindful that "in today's reality, a terrorist organisation is likely to have considerable military capabilities." Indeed, "[a]t times they have military capabilities that exceed those of states."
In discussing the personal scope of application of IHL, also known as ratione personae, the present article therefore analyses when (alleged) terrorist organisations can qualify as parties to a conflict. It does so by first defining the scope of the term "terrorist organisation" for the purposes of the present contribution, followed by a discussion of the possible parties to an international armed conflict, and subsequently, the requirements a terrorist organisation must fulfil to qualify as a party to a non-international armed conflict. The next section demonstrates that the inquiry whether terrorist organisations can constitute parties to armed conflicts is not merely a theoretical exercise, since convictions for terrorist acts in recent Belgian case law revolve around the question of whether alleged terrorist groups or networks are to be considered as fighting as parties to armed conflicts in, mainly, Syria, Iraq, and Turkey. Some critical comments are made on the said case law, before ending with concluding remarks.