Lawmaking Under Pressure Symposium: International Humanitarian Law Governing Non-International Armed Conflicts–Treaty Law and Customary International Law

[At the time of conceptualizing this post, Iris Mueller was a thematic legal adviser in the ICRC legal division, working mostly on customary IHL. Previously, she was a legal adviser on the update of the ICRC commentaries on the 1949 Geneva Conventions and 1977 Additional Protocols. She continues to work for the ICRC in a legal capacity.]

The regulation of non-international armed conflicts by international humanitarian law (IHL) may seem evident today. Giovanni Mantilla’s book “Lawmaking under pressure – International Humanitarian Law and Internal Armed Conflict” provides a stark reminder that, historically, this understanding was far from a given.

This realization is striking when thinking of the present firm acceptance of IHL governing non-international armed conflicts: In various international fora, there are regular calls on parties to non-international armed conflicts to act in accordance with their obligations under IHL, for example. Violations of IHL during non-international armed conflicts are widely deplored and condemned. Serious violations of IHL – war crimes – in non-international armed conflicts are investigated at the domestic and international level, and individuals alleged to be responsible for such violations are prosecuted and tried. While “it is a matter of controversy whether human rights law also binds non‑State actors” (see here at p. 54: ), there is normally no doubt that non-state parties to armed conflict are bound by IHL applicable to non-international armed conflict. In 1986, the International Court of Justice even described the rules defined in Article 3 common to the 1949 Geneva Conventions (common Article 3; CA3) as “elementary considerations of humanity” (see here at para. 218: ).

The significance of this development in the acceptance of IHL governing non-international armed conflict is highlighted further when having in mind that, according to the ICRC’s legal analysis (see thread here), over the last 20 years, the number of non-international armed conflicts has more than doubled: from less than 30 to more than 80. The loss of life, suffering and destruction caused by non-international armed conflicts around the world are devastating. The importance of the existence of – and adherence to – IHL governing non-international armed conflicts therefore cannot be overstated.

And indeed, fortunately, non-international armed conflicts are today subject to a solid body of IHL treaty provisions. Foremost among them is common Article 3, already referred to above. Adopted in 1977, the Protocol Additional to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of Non-International Armed Conflicts (Additional Protocol II), “develops and supplements” common Article 3. A number of other treaties relevant for the armed conflict context also apply to non-international armed conflicts (see the 2001 amended Article 1 to the 1980 Convention on Prohibitions or Restrictions on the Use of Certain Conventional Weapons Which May be Deemed to be Excessively Injurious or to Have Indiscriminate Effects, for example).

As Mantilla describes, the adoption of common Article 3 and Additional Protocol II was the outcome of intense negotiations and was far from guaranteed. Indeed, as Mantilla notes in the book’s introduction, “[s]ince its inception, CA3 was hailed as revolutionary”. Common Article 3’s adoption in 1949 is particularly remarkable when considering that, at the time, in the area of international and regional human rights law, States had only just begun to open themselves up to international law.

Owing to the specificities of their drafting histories, another shared feature of common Article 3 and Additional Protocol II is their relative brevity, compared with the extent and detail of the provisions governing international armed conflicts, as contained notably in the 1949 Geneva Conventions as such and the 1977 Protocol Additional to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of International Armed Conflicts (Additional Protocol I). While, crucially, common Article 3 inter alia provides fundamental protections for any person “not taking an active part in the hostilities”, it contains no provisions as such regulating the conduct of hostilities, for example. Similarly, while Additional Protocol II adds important elements to the content of common Article 3 – and, for instance, provides at least some norms on the conduct of hostilities, such as the prohibition of attacks against civilians – it is much shorter than Additional Protocol I.

It may partly have been this relative scarcity of treaty IHL governing non-international armed conflicts that prompted the Intergovernmental Group of Experts for the Protection of War Victims, convened in January 1995 pursuant to the 1993 International Conference for the Protection of War Victims, to recommend that: “the ICRC be invited to prepare, with the assistance of experts on IHL representing various geographical regions and different legal systems, and in consultation with experts from governments and international organisations, a report on customary rules of IHL applicable in international and non-international armed conflicts, and to circulate the report to States and competent international bodies” (see here). The fact that, unlike common Article 3, Additional Protocol II does not apply in all non-international armed conflicts – for lack of ratification or when its specific applicability criteria are not fulfilled – may have been another reason.

Following the endorsement of the above recommendation by the 26th International Conference of the Red Cross and Red Crescent in December 1995, the ICRC embarked on the task thus entrusted to it. As described by Mantilla in his book’s conclusion, this ultimately resulted in the publication, in 2005, of the ICRC’s study on customary IHL (see also here, with regular updates of the study’s practice part).

Based on the practice and opinio juris of States worldwide collected and assessed, one of the study’s main results was that the large majority of the 161 rules of customary IHL rules it identified was found to be equally applicable in international and non-international armed conflicts.

As noted by one of the study’s authors, “State practice and customary humanitarian law have thus filled important gaps in the treaty law governing non-international armed conflicts. The divide between the law on international and non-international armed conflicts, in particular concerning the conduct of hostilities, the use of means and methods of warfare and the treatment of persons in the power of a party to a conflict, has largely been bridged. But this is not to say that the law on international and non-international armed conflicts is now the same. Indeed, concepts such as occupation and the entitlement to combatant and prisoner-of-war status still belong exclusively to the domain of international armed conflicts” (see here at p. 487: ).

As Mantilla points out in his book’s conclusion, “[i]n a relatively short time [the study] came to be increasingly cited by international and domestic judicial bodies and national militaries”; many international and domestics bodies continue to do so until today.

That said, as also observed by Mantilla, States have not necessarily embraced all the findings of the study (see notably here). This should not be seen as surprising. Already in his foreword to the study, then member of the ICRC and former director of the ICRC department of international law and policy Dr Yves Sandoz noted: “The study is a still photograph of reality, taken with great concern for absolute honesty, that is, without trying to make the law say what one wishes it would say. I am convinced that this is what lends the study international credibility. But though it represents the truest possible reflection of reality, the study makes no claim to be the final word. … May it be read, discussed and commented on. May it prompt renewed examination of international humanitarian law and of the means of bringing about greater compliance and of developing the law.”

This process continues, including as regards the study’s findings on IHL applicable to non-international armed conflicts.

Reading Giovanni Mantilla’s book on the challenging origins of IHL governing non-international armed conflict and seeing how far its acceptance has come since then are an encouragement in that process. The victims of non-international armed conflicts worldwide deserve no less than ongoing commitment to it.

(The views expressed here are those of the author alone and do not necessarily reflect those of the ICRC.)