International humanitarian law (IHL), also known as the law of armed conflict, the law of war or jus in bello, is a set of rules that seek, for humanitarian reasons, to limit the effects of armed conflicts. IHL regulates the conduct of belligerent parties by imposing restrictions on the means and methods of warfare that may be employed and by ensuring the protection and humane treatment of persons who are not or are no longer taking a direct part in the hostilities.
IHL comprises those rules of international law – found mainly in the four Geneva Conventions of 1949 and their Additional Protocols, in weapons treaties, and in customary law – which establish minimum standards of humanity that must be respected in any situation of armed conflict. Since IHL is specifically designed to resolve humanitarian issues arising from armed conflict, it neither governs the legitimacy or legality of going to war, nor does it shed light on how peace can be restored. Still, IHL is inextricably linked to the return to sustainable peace, and some IHL obligations explicitly extend beyond the temporal limits of armed conflict and into the peacebuilding process.
This overview aims to address the ways in which IHL intersects with the pursuit of peace. Even before the codification of the very first Geneva Convention in 1864, there was debate on whether imposing limits on the conduct of parties in war actually constitutes an obstacle to peace by legitimizing war, or whether it can make a contribution in the pursuit of peace. These questions have been the subject of debate over many decades, and this piece can only touch briefly upon IHL's role among the wider body of international law, the distinction between jus in bello and jus ad bellum, and some of the ways in which IHL may contribute to pathways to peace.
The latter issue, in particular, merits further research and inquiry. In a Global Initiative to Galvanize Political Commitment to International Humanitarian Law launched in September 2024 by six States and the International Committee of the Red Cross (ICRC),Footnote 1 the link between IHL and peace will be one focus issue for the ICRC's work over the next two years.
Undermining peace or facilitating it?
Historically, there have been apprehensions that IHL, as a body of law which regulates the conduct of all belligerent parties, without judgement as to their justification for resorting to armed force, may detract from the central purpose of modern international law and indeed the moral and political imperative to maintain and fortify international peace.
The debate over whether IHL legitimizes armed conflict has existed since before the first Geneva Convention of 1864. Critics have argued that IHL, along with the broader humanitarian movement, inadvertently condones armed conflict rather than advocating for its abolition. This criticism first came from the pacifist movement at the end of the nineteenth century, when war was not yet outlawed, as it is today – albeit with some exceptions – by the United Nations (UN) Charter. As the pacifist Bertha von Suttner wrote in 1912, “[s]o-called international law – dry legalism – does not fit into the peace movement, about as little as the Red Cross does”.Footnote 2 This criticism was not entirely unjustified, as many international lawyers and States preferred to concentrate on regulating war in those days, not believing that war could be abolished or indeed not wanting its abolition. When Henry Dunant received the Nobel Prize for Peace in 1901, von Suttner asked him to write a few lines explaining that he had received it for his work on peace and not for his Red Cross work, because, as she wrote, “in general, the world only knows you as the founder of an institution that makes war easier”. She wanted proof from him that he was one of those who “(after war has been made easier) wants to abolish war”.Footnote 3 Early social democrats like Rosa Luxemburg similarly sought to “expose the bourgeois attempts to restrain militarism as pitiful half-measures”,Footnote 4 considering that “[w]orld peace cannot be secured by such utopian or basically reactionary plans as international courts of arbitration composed of capitalist diplomats, diplomatic agreements concerning ‘disarmament’ … and the like”.Footnote 5 The Disarmament Committee of the Women's International Organisations at the Conference for the Reduction and Limitation of Armaments of February 1932 stated: “We have no belief in the possibility of humanising warfare nor of defending civil populations from poison gases or other modern methods of waging war.”Footnote 6
The founders of the ICRC, on the other hand, saw no contradiction in supporting peace while at the same time working for the humanization of war. Gustave Moynier, the first president of the organization, was among the first to outline the ICRC's position in refraining from joining the pacifist movement while at the same time supporting its aims.Footnote 7 In Moynier's words, “[t]he Red Cross also counts, let us say it loudly, on the contagious spectacle it gives of a firm faith in the fraternity of peoples, advocated by all the apostles of peace as their strongest support”.Footnote 8 At the same time, the ICRC's founders were clear that while the protection of human dignity during armed conflict and peace are mutually reinforcing, they are not identical objectives.Footnote 9 As Daniel Palmieri shows in his article in this issue of the Review, the position of the ICRC in this respect has essentially remained the same until today: IHL seeks to lessen the evils of war, and thereby can indirectly contribute to restoring peace. Throughout its history, however, and with some notable exceptions, the ICRC has generally refrained from being involved in conflict prevention or peacebuilding and has concentrated on its mission to alleviate suffering for the victims of armed conflicts on all sides.
Today, similar debates persist. Some voices argue that the regulation of armed conflicts works to make the inevitability of wars acceptable. So long as they are fought “humanely”, wars are more “digestible”, thus enabling prolonged conflicts like the so-called “war on terror”.Footnote 10 The emphasis should instead be on total disarmament and the abolition of war. Others, including important feminist voices, have cautioned that the regulation of war detracts from the need to concentrate on war's underlying root causes, and in particular the militarization of societies, gender inequality, global economic inequalities and the arms trade.Footnote 11 We have been warned against war as a “state of mind” that permeates legal thinkingFootnote 12 and makes us accept too easily rules that contain fewer safeguards against violence and abuse than peacetime rules do.Footnote 13
This brief overview cannot do justice to all the facets of this rich and important debate. Practitioners of IHL need to be ever mindful of these warnings, especially at a time when the inevitability of war is mentioned with alarming frequency, and when the international security discourse speaks of security threats in such abstract terms that the reality of men, women and children who bear the consequences of armed conflict is invariably obscured, glossed over by military and political euphemisms.
To address some of these questions and warnings, the first thing to recall is that IHL must be understood as only one limited part of the wider construct of international law.
IHL acknowledges the reality of wars and offers a normative framework to curtail their catastrophic humanitarian costs to the extent practicable; it does not legitimize, condone or legalize the resort to armed force. The objective of IHL is to regulate the conduct of parties in armed conflict, once it breaks out, by limiting the scale and severity of suffering. It is oriented neither towards preventing armed conflicts, nor towards resolving them by addressing their underlying political, social, economic or other motivations – some of these considerations are addressed by jus ad bellum and international law in general. It is merely one piece of the puzzle of international law. It is the role of the UN Charter to prevent armed conflicts and preserve international peace and security.
At the same time, IHL treaties and the positions of States adopting them make very clear that the existence of IHL as a legal framework cannot be invoked to justify any resort to force between States.Footnote 14 The 1949 Diplomatic Conference stated that
its work having been inspired solely by humanitarian aims, its earnest hope is that, in the future, Governments may never have to apply the Geneva Conventions for the Protection of War Victims …. [I]ts strongest desire is that the Powers … may always reach a friendly settlement … so that peace shall reign on earth for ever.Footnote 15
Similarly, the preamble of Additional Protocol I states that the High Contracting Parties proclaim their wish for peace and that “nothing in this Protocol or in the Geneva Conventions of 12 August 1949 shall be construed as legitimizing or authorizing any act of aggression or any use of force inconsistent with the Charter of the United Nations”. A number of weapons treaties and humanitarian disarmament treaties also affirm the link between disarmament and peace. For example, the Convention on Certain Conventional Weapons states as its goal “the ending of the arms race and the building of confidence among States, and hence … the realization of the aspiration of all peoples to live in peace”.Footnote 16
At the time of writing, there does not seem to be empirical evidence to demonstrate that respect for IHL has contributed to the multiplication or prolongation of armed conflicts; nor, for that matter, that respect for IHL has contributed to shortening armed conflicts. Nor are we aware of evidence showing that the mere existence of a body of law insisting on preserving humanity in armed conflicts has a demonstrable impact on decisions to go to war in the first place.
That being said, it is important that the scope of application of IHL not be extended beyond the situations which it was meant to regulate. There can be a temptation by States to expand IHL's geographic, material, temporal or personal scope of application in situations which do not qualify as an armed conflict, in order to justify a use of force that would not be allowed in peacetime, including in situations of violence below the threshold of armed conflict.Footnote 17 Today, there is a real risk that
the law simply adjusts to become an apology for what some states feel they need to do … [and] that the law of war is simply invoked in a rather casual way to explain away questions about the morality, wisdom and legitimacy of all sorts of activity.Footnote 18
It must be made clear that IHL only applies in armed conflict situationsFootnote 19 as they are defined under international law.Footnote 20 There is also a danger that IHL – instead of being applied as the protective body of law that it was designed to be – is simply invoked to justify unchecked levels of violence by stretching beyond breaking point the rules on the conduct of hostilities. These rules require a balancing of military necessity and humanity that is designed to allow parties to conflict to defeat the military forces of the enemy, and only those forces, but their ultimate purpose is to protect civilians against the dangers of military operations. IHL, restrictive though it is meant to be for the exceptional situation of armed conflict, is nonetheless in some areas more permissive than human rights law when it comes to using force against people or depriving them of liberty.Footnote 21 It is therefore sometimes invoked to displace peacetime rules, especially international human rights law, in order to justify wide-reaching powers of the belligerents. In order to avoid abuse in this area, IHL, like all other bodies of law, must be read in light of other applicable rules of international law, especially human rights law.Footnote 22
IHL is indeed at risk of being misused to justify excessive amounts of military violence. While it does acknowledge that in armed conflict military operations take place and will cause death and destruction, its object and purpose are not to fuel more violence but to limit its effects on the victims, and to limit their number. Evidence over the years has shown that IHL does provide a measure of humanity when respected. This, however, requires that, while being an integral part of international law, IHL must be strictly kept separate from another part: jus ad bellum.
Why jus ad bellum and jus in bello must continue to remain separate bodies of law
If the UN Charter is the modern law of peace, and IHL is the law of war, how can the law of war be disconnected from the law of peace?
Jus ad bellum is a distinct body of international law which governs the legality of the resort to armed force between States. The general prohibition against the use of force amongst States and the very limited exceptions thereto, set out in the UN Charter or reflected in custom, are the core norms of jus ad bellum. The primary goal of jus ad bellum is to ensure, as far as possible, international peace and security between States by eliminating war altogether.Footnote 23 It does so by prohibiting States from resorting to armed forceFootnote 24 except for reasons of self-defenceFootnote 25 or collective security (as authorized by the UN Security Council),Footnote 26 requiring the peaceful resolution of disputes instead.Footnote 27
Unlike jus ad bellum, which addresses the justification(s) for resorting to war, jus in bello is synonymous with IHL. Jus in bello is therefore aimed at regulating and imposing limits on the conduct of belligerent parties, regardless of the reasons for going to war or the justness of the causes for which they are, or claim to be, fighting.Footnote 28 Thus, when there is an outbreak of armed conflict, irrespective of its actual, claimed or perceived legitimacy or lawfulness under jus ad bellum, the protective rules of jus in bello kick into action and bind all belligerent parties equally.Footnote 29
Though jus ad bellum and jus in bello have distinct objectives and domains of application, there have been attempts at conflating the two, especially in the context of contemporary armed conflicts. The argument goes that in order to maintain the peace, would-be aggressors have to be deterred by being put at a disadvantage compared to law-abiding parties, and no incentive or legitimacy should be given to would-be aggressors by putting them on the same footing as defenders, as IHL purportedly does.Footnote 30
For instance, some scholars (and States) argue that the jus in bello obligations of a belligerent party should be shaped by the legality of their resort to armed force under jus ad bellum. The party which is fighting for a “just” cause ought to have a greater leeway in the manner in which it applies jus in bello norms to its conduct vis-à-vis the other party. This entails interpretations of what qualifies as “military advantage”, “proportionality” or “military necessity” that are relative to the justness of the cause, with the “just” party being entitled to greater use of force and protection against accountability, and the other party to less.Footnote 31 Combatant immunity is similarly challenged, with the argument that accountability for the crime of aggression should not be limited to leaders of a State, but should extend to its soldiers, sailors and pilots.Footnote 32
The blurring of the lines between jus ad bellum and jus in bello would, however, lead to the erosion of humanitarian protections in armed conflict. The reason for IHL to be strictly separate from jus ad bellum is first and foremost humanitarian: there are victims on all sides of a conflict, and they all deserve protection. Indeed, at the very origin of the first Geneva Convention is the idea that all wounded and sick soldiers must be cared for, no matter which side they are on. This has been the theme of protection throughout the history of IHL: the means and methods of warfare are subject to limitations for all parties, and anyone not or no longer fighting must be protected.Footnote 33 Also, as States inevitably see themselves as the victims of aggression from the other side, to undermine combatant immunity would inevitably invite an unravelling of the prisoner of war status and the protections that come with it.
This strict separation between jus ad bellum and jus in bello is reflected in Article 1 common to the four Geneva Conventions (common Article 1), which imposes the obligation “to respect and to ensure respect for the … Convention[s] in all circumstances” (emphasis added), indicating that the application of the Geneva Conventions (and IHL in general) is not contingent on the legal (or moral) justification(s) for an armed conflict.Footnote 34 It is also explicitly affirmed by the preamble to Additional Protocol I, which states that IHL provisions “must be fully applied in all circumstances … without any adverse distinction based on the nature or origin of the armed conflict or on the causes espoused by or attributed to the Parties to the conflict”, and has been reiterated in various judicial decisions.Footnote 35
Consequently, the ICRC has consistently maintained that there must be strict separation between jus in bello and jus ad bellum – jus ad bellum considerations have no effect on the application of IHL rules, which uniformly bind all belligerent parties, with no regard to who started the fighting or why.Footnote 36 So, while both jus ad bellum and jus in bello may apply concomitantly through their own, distinct rules, they can never influence the application of one another. Nor do they displace each other: the applicability of IHL does not displace the application of the UN Charter.Footnote 37
In sum, it is only by upholding the strict separation of jus ad bellum and jus in bello that IHL can contribute in concrete and pragmatic ways to alleviating the suffering of all people affected by armed conflict, regardless of which side they are on.
How can IHL contribute to finding pathways to peace?
IHL cannot prevent wars or end them, nor is that its function. However, though there is no empirical evidence at the time of writing to demonstrate that armed conflicts have been short-lived or prolonged relative to their level of adherence to IHL, IHL is certainly equipped to play a part in the peacebuilding process and post-conflict recovery, albeit indirectly.
Firstly, respect for IHL rules can foster conditions that promote peace. For instance, by requiring the humane treatment of detainees,Footnote 38 proper handling of the dead,Footnote 39 and medical care for civilians and combatants alike,Footnote 40 IHL protects and upholds the human dignity, physical integrity and life of those not or no longer fighting, without discrimination. Further, it can prevent dehumanization and deepening spirals of retribution and violence.Footnote 41 Respect for IHL can remove at least some obstacles to peacemaking: fewer displaced people, refugees and destroyed homes mean less effort spent on negotiating return or resettlement; better respect for safeguards in detention means more clarity and simplicity in determining whom to release and when; the resolution of missing persons cases and the reunification of families means relief from the collective anguish and resentment that can hinder peace; and fewer explosive remnants of war mean a less onerous clearing burden and a smoother return to productive urban and agricultural life.Footnote 42
Respect for IHL can also facilitate a return to peace by reducing the material cost of war on civilians and civilian objects, thus potentially contributing to the restoration of stability in the war's aftermath. By specially protecting objects indispensable to the survival of the civilian population (such as foodstuffs, water sources and livestock),Footnote 43 hospitals,Footnote 44 schools,Footnote 45 and religious, cultural and historic monuments,Footnote 46 IHL helps conserve these resources and lay the groundwork for rebuilding villages, cities and societies after war. Moreover, ensuring that essential civilian infrastructure and civilian institutions that are critical for domestic and international commerce remain operational helps preserve some measure of economic security for the population, and can make the resumption of peaceful life at the end of an armed conflict quicker. In sum, better respect for IHL can make reconstruction less costly and onerous once war is over.
By a similar token, systematic IHL violations undermine the reputation of belligerent parties, which may create an additional obstacle to dialogue toward peace. Non-State armed groups, especially those seeking legitimacy and the support of the international community, can seek to adhere to (or to be seen to adhere to) IHL norms, so as to be accepted into political processes and governance structures in post-conflict scenarios.Footnote 47
Secondly, IHL encourages the belligerent parties to create humanitarian spaces that protect victims of war, which may, in the long run, serve to inspire a spirit in which humanitarian agreements, rather than violence, become a trusted method underpinning future peace negotiations. For example, parties may enter into “special agreements”Footnote 48 for the establishment of safety and neutralized zones,Footnote 49 for cooperation in the search for missing persons,Footnote 50 for the recovery and exchange of remains of the dead,Footnote 51 for the reciprocal release of detainees,Footnote 52 or for temporary ceasefiresFootnote 53 to facilitate humanitarian reliefFootnote 54 or evacuation of the wounded.Footnote 55 These temporary measures can be first steps towards building mutual trust between the belligerent parties, thereby showing ways to resolve at least part of their dispute peacefully.Footnote 56 Importantly, IHL also contains detailed rules for the release and repatriation of prisoners of war and civilians at the end of hostilities.Footnote 57
If agreed by all parties to the armed conflict, humanitarian organizations like the ICRC may perform a variety of humanitarian activities under the framework of IHL. Such activities can constitute small, modest bridges to peace, such as providing safe passage to participate in peace talks, bringing detainees home, sharing information about missing people, accompanying members of separated families across front lines and reuniting them with their relatives, escorting and enabling the work of humanitarian demining missions through combat zones, or conveying messages to organize ceasefires, simultaneous releases of detainees or evacuations from besieged areas.Footnote 58
Thirdly, IHL supports peacebuilding by providing a framework for transitional justice and accountability. On the one hand, IHL operates on the basis that combatants in international armed conflicts are immune from prosecution for merely participating in hostilities. It encourages clemency and forgiveness at the end of non-international armed conflicts by including an obligation of the authorities in power to endeavour to grant the broadest possible amnesties to persons who have taken a direct part in the hostilities (without having committed war crimes).Footnote 59 Such amnesties, where lawful, are a facet of transitional justice which would go a long way in facilitating post-war reconciliation. On the other hand, IHL also seeks to support sustainable and lasting peace by providing accountability for war crimes and requiring States to investigate and prosecute them.Footnote 60 This too is an important part of the transition to peace, restoring a measure of justice to the victims, acknowledging their suffering, contributing to trust in legal institutions, and sending a strong signal against impunity and repetition of such violations. Such actions should make it easier for all levels of society to take steps toward peace.
Lastly, several IHL rules continue to apply in the aftermath of armed conflict, protecting people in the transition from conflict to peace. For example, even (years) after the end of an international armed conflict, the treatment of prisoners of war and civilian internees in detention continues to be regulated by IHL until their final release and repatriation.Footnote 61 Similar protections are also available to persons deprived of their liberty in connection with a non-international armed conflict.Footnote 62 Belligerent parties remain bound by obligations related to the restoration of family links, accounting for the missing and the dead, the prosecution and punishment of those responsible for war crimes and serious violations of IHL, and the clearance of unexploded ordnance and explosive remnants of war, even after the end of an armed conflict.Footnote 63
Conclusion
As experience has demonstrated, no legal framework has so far been capable of entirely stopping wars – the factors leading to armed conflicts are too complex. The urgency to pursue peace and counter the discourse of the inevitability of war must therefore continue, and the trend of multiplying conflicts must be reversed. No amount of IHL and no amount of humanitarian assistance could ever make wars free of suffering – which makes it difficult to maintain the notion that the mere existence of a legal framework designed to regulate what has otherwise been outlawed plays any role in decisions to engage in armed conflicts.
In the meantime, even though IHL does not prevent wars, it does provide a measure of humanity when they break out, and is a crucial piece of the puzzle in modern international law's quest for international peace and security. In the absence of the restraints imposed by IHL, however, armed conflicts would likely become more barbaric, destructive and inhumane. Without IHL's enabling framework, humanitarian actors would struggle even more to perform their essential work, such as delivering relief and assistance to civilian populationsFootnote 64 and engaging with parties to protect those deprived of liberty.Footnote 65 IHL provides many rules and incentives which, when respected, may eventually facilitate a way out of conflict. Humanitarian restraint in war and the quest for peace are not mutually exclusive, they are complementary endeavours.
Open access
