Law of Armed Conflict

Author: Anne Dienelt and Imdad Ullah

BOX 14.1

Required knowledge: Public International Law/Sources of International Law, Public International Law/Human Rights Law, Public International Law/Use of Force, Public International Law/Subjects and Actors in International Law

Learning objectives: Understanding the law of armed conflict (jus in bello) considering its historical roots, evolutions over the period of various centuries, core principles and norms of the law of armed conflict, and some current challenges.

BOX 14.2. Interactive Exercises Access interactive exercises for this chapter[1] by positioning your smartphone camera at the dot-flled box, also known as a QR code.

A. Introduction edit

The persistence of violence and conflicts gave way to efforts to regulate it, first in terms of regulating weapons as in the (Eurocentric) 1868 St. Petersburg Declaration, and later on by specifically protecting civilians and the civilian population from the conduct of hostilities in the four universal Geneva Conventions and their additional protocols (often described as 'international humanitarian law' or 'IHL'). Rules and principles to limit the harm to civilian objects and the civilian population were present as early as the recorded human history. The content of these rules and principles was (and is) not purely humanitarian. There is a constant struggle with balancing military necessities with humanitarian aims. This also explains why not all rules and principles follow humanitarian motives; as warfare has always been cruel and brutal.[2] The jus in bello (Latin: 'right in war') should not be mixed with the jus ad bellum (Latin: 'right to war')[3] (or jus contra bellum [Latin: 'right against war']), which refers to the prohibition of the use of force and its exceptions. Even though aggression is prohibited (see Art. 2(4) UN Charter[4]), and its exceptions (e.g., see article 51 of the UN Charter). Even though aggression is prohibited, the law of armed conflict includes rules and principles regulating how an armed conflict can be conducted lawfully.

BOX 14.3 Advanced: Separation of jus ad bellum and jus in bello In the jus ad bellum, the current situation in Ukraine is phrased as an unlawful aggression by Russia against Ukraine. In the jus in bello, Russia and Ukraine are bound by the same legal standards, namely the law of armed confict, even though Russia started the war with an unlawful invasion.

This chapter explores how civilians and the civilian population are protected in war. How is the tension between military necessity and humanitarian aims resolved? What is lawful conduct in war? It begins with a historical overview to better understand the origins of the law of armed conflict. It then turns to the classification of a conflict (non-international or international), which determines the specific legal framework in the law of armed conflict that regulates the specific conduct of hostilities. Afterwards, the relevance of customary international law is highlighted by reference to the core principles of the law armed conflict, such as distinction or proportionality. The various actors in the law of armed conflict are briefly described, leading to current challenge within the law of armed conflict, including the protection of specific groups and objects particularly vulnerable in war as well as new technologies of warfare. The chapter concludes with a brief description of how the law of armed conflict can interact with other fields of public international law.

B. Historical overview edit

The modern law of armed conflict emerged as a result of historical norms and traditions. The terrible harm witnessed by Henry Dunant[5] after the battle of Solferino in 1859 served as a catalyst for this development.[6] Parallel to States coming together to regulate a further warfare escalation with new weapons emerging in the 19th century, influential figures of the peace movement, such as Dunant or Bertha von Suttner,[7] campaign to adopt regulations to limit the suffering of the wounded. The creation of the International Committee of the Red Cross (ICRC) in 1863, the first Geneva Convention for the Amelioration of the Condition of the Wounded in Armies in the Field of 1864, and eventually also the 1899/1907 Hague Regulations aim at protecting the wounded in wars. In the beginning, 16 States from mainly Europe and Latin America participated in the first Geneva Conference, which resulted in an agreement on principles that emphasised the care for wounded individuals on the battlefield, regardless of their nationality. Later on, the Hague Peace Conferences further expanded the regulations and also includes rules governing naval warfare, which were subsequently confirmed and amended in the four 1949 Geneva Conventions and the two 1977 Additional Protocols (AP I and II).

The 19th-century regulations and the 1899/1907 Hague Regulations could not stop two world wars (and did not intend to do so), nor were they able to prevent all human suffering. However, the two world wars and their devastating consequences for the civilian population underscored the need for universally applicable rules and regulations to curtail the horrendous character of modern warfare. Consequently, diplomatic conferences are held to agree on rules to care for the sick, wounded, and prisoners of war. These conferences also intended to expand the scope of earlier conventions. The 1949 Geneva Conventions enshrine rules on protecting civilian populations during war and under foreign occupation and generally regulate international armed conflicts. Their common article 3 addresses non-international armed conflicts.[8] In the meantime, the Vietnam War, among others, highlighted the need for further warfare regulation. The two Additional Protocols (APs) from 1977 were also adopted in light of colonial wars. While AP II focuses on non-international armed conflicts and includes a set of rules applying to conflicts between States and non-State actors, AP I contains rules that extend the protection of the four Geneva Conventions.

C. Classification of an armed conflict edit

When analysing a specific armed conflict, first, one must determine the kind of armed conflict. This so-called classification[9] refers to two categories of conflict: an international armed conflict (IAC) and a non-international armed conflict (NIAC). IACs between two or more States are regulated by the four Geneva Conventions, AP I and custom,[10] while NIACs between a State and a non-State actor or between several non-State actors on the territory of a State[11] are governed by common article 3, AP II together with customary rules and principles

BOX 14.4 Example: NIACs Two examples of NIACs are the conflict in Colombia with the FARC guerrilla group fighting the government, and in the aftermath of 9/11, the US war with Al-Qaeda across several States.[12]

D. Core principles of the law of armed conflict edit

In many instances, parties to a conflict have treated prisoners humanely and exchanged prisoners of war in the aftermath of conflicts. Due to belligerent States' consistent practice and opinio juris, these practices gradually emerged as customary rules.[13] These customs[14] were also codified in treaties, such as the 1899/1907 Hague Regulations, the 1949 Geneva Conventions or the 1977 Additional Protocols.

All fundamental principles of the law of armed conflict, such as humanity, distinction, military necessity, proportionality, and the obligation to take all feasible precautions, enjoy the status of customary law,[15] and apply in IACs and NIACs. Their objective is to 'humanise' warfare without challenging the justifications for the initial aggression (important separation of the right to war from right in war). They assist in maintaining the balance between military necessity and humanitarian protection. To be a lawful attack, all principles as well as specific regulations have to be observed.

I. Humanity edit

Following the principle of humanity, States have adopted norms prohibiting cruel and inhuman treatments of opponents, especially regarding prisoners of war.[16] Today, the wounded, sick, shipwrecked, and non-combatants also enjoy protection. Regarding NIACs, the principle can be found today in common article 3, which prohibits the inhumane treatment of all those persons not participating in hostilities.[17] In IACs, article 75(1) AP I emphasises the humane treatment of individuals without discrimination.[18] The principle of humanity enjoys customary status,[19] applicable to States and non-States alike.

II. Distinction edit

The principle of distinction determines who and what can be targeted in the conduct of hostilities (see e.g. article 48 AP I). It has emerged as a cardinal principle in treaty as well as in customary law.[20] It underscores that civilians and civilian objects are never a lawful target, while military objects and combatants can generally be attacked lawfully. Until and unless civilians participate in hostilities directly, they are legally protected from belligerent attacks.[21] Nevertheless, under very limited conditions, and only if proportionate, collateral damage to civilians and civilian objects can be lawful. The 1899/1907 Hague Regulations (article 25) do not specifically use the word 'civilians', but they outlaw 'the attack or bombardment, by whatever means, of towns, villages, dwellings, or buildings which are undefended'.[22] Regarding IACs, article 57 (2)(b) AP I stresses that only direct armed attacks against combatants and military objects are lawful. In NIACs, article (13)2 AP II prohibits attacks on the civilian population, and treating civilians and civilian objects as an object of attack. It is also outlawed to cause terror among the civilians by indiscriminate attacks.[23] Parallel in IACs, Art. 57(1) AP I stipulates that 'in the conduct of military operations, constant care shall be taken to spare the civilian population, civilians and civilian objects'.

III. Military necessity edit

Furthermore, actions that are necessary to accomplish a legitimate military purpose and are not otherwise prohibited by IHL can be lawful. In treaty law and custom, the only lawful military purpose is to weaken the military capacity of the other belligerent parties.[24] Article 23(g) of the 1899/1907 Hague Regulations prohibits 'to destroy or seize the enemy's property, unless such destruction or seizure be imperatively demanded by the necessities of war'.[25]

IV. Proportionality edit

Proportionality is inter alia enshrined in article 51(5)(b) AP I which states that 'an attack which may be expected to cause incidental loss of civilian life, injury to civilians, damage to civilian objects, or a combination thereof, which would be excessive in relation to the concrete and direct military advantage anticipated'. It puts the damage caused by military activities into relation with the military advantage and requires that the effects of the means and methods of warfare cannot be disproportionate to the military advantage.[26] Hence this principle balances military necessity with humanitarian considerations. It is common understanding that 'direct military advantage' refers to the operation as a whole and not separate parts of the attack.[27] While military necessity speaks of the criteria to choose a military target, proportionality lays down the limits of a specific military action to neutralise a target.

V. To take all feasible precautions edit

The principle of precaution was initially set out in article 2 of the 1907 Hague Convention (IX). It provides that given the presence of a military target inside an undefended town or port, the military commander to 'take all due measures in order that the town may suffer as little harm as possible'.[28] Additionally, article 57 AP I states that it is incumbent upon the warring parties to 'do everything feasible to verify that the objectives to be attacked are neither civilians nor civilian objects and are not subject to special protection'.

E. Actors in the law of armed conflict edit

I. States edit

States as traditional subjects of international law[29] play an important role in the law of armed conflict: States start armed conflicts, they participate in hostilities, they occupy territory, and they negotiate armistices. In collective efforts, States assembled at international peace conferences, like the ones leading to the conclusion of the 1964 Geneva Convention, the 1899/1907 Hague Regulations, and the 1949 Geneva Conventions.

II. Non-State Actors edit

Over the past decades, many NIACs took place, with one State fighting an organised armed group or several ones within its territory, and vice versa. These situations are regulated by common article 3 to the Geneva Conventions and AP II. In NIACs, rebel and terrorist groups can be belligerent parties and lawfully participate in the hostilities as armed non-State actors under the law of armed conflict. They are directly addressed in common article 3 and in AP II.

BOX 14.5 Advanced: Non-State Actors The treatment of non-State actors under non-international armed conflicts does not grant them any legitimacy. This regulation only aims to safeguard innocent civilians in armed conflicts. Despite their active role in conflicts, non-State actors do not participate in the law-making procedure in the law of armed conflict. They are not a party to any treaty, since treaties are concluded between States exclusively. In peace negotiations, in contrast, non-State actors participate together with States. their actions are also indirectly considered when interpreting the law of armed confict,[30] and when identifying rules and principles of customary law.[31] Compliance of non-State actors with the law of armed conflict still represents a challenge.[32]

III. The International Committee of the Red Cross edit

The International Committee of the Red Cross (ICRC) is the "guardian"[33] of the law of armed conflict. It is mandated to protect people affected by armed conflicts. It is a subject of international law and has international legal personality. But the ICRC enjoys a special international legal status that is different than the one from NGOs, which are not subjects of international law, or international organisations, who mostly enjoy a derivated subjectivity in international law.[34] The ICRC is guided by seven principles: humanity, impartiality, neutrality, independence, voluntary service, unity & universality.[35]

F. Current challenges in the law of armed conflict edit

I. Protected Groups and Objects edit

States originally created the law of armed conflict to spare the civilians and the civilian population from the consequences of war. While the principle of distinction generally prohibits direct attacks against civilians, some provisions of the Geneva Conventions and their additional protocols address other specific groups or objects, such as medical personnel and infrastructure, cultural property, or the natural environment. Their protection is often linked to the protection of civilians and civilian objects, but the provisions install special protection for specific protected groups and objects that differs from the general protection of civilians and civilian objects.

1. Medical Personnel edit

The 1864 Geneva Convention was concluded to take care of the wounded and sick combatants of all belligerent States who were hors de combat (French: 'out of the battle'). Without medical personnel and medical care, their protection would have remained meaningless. Hence civilians and militaries officially assigned to medical purposes temporarily or permanently are of high value in war due to their essential role in medical care. Medical personnel, medical units, and medical establishments enjoy protection and cannot be targeted lawfully.[36] They are protected when fulfilling their medical duties in conformity with medical ethics.[37] But once they participate in the hostilities, they lose their protection.[38] But once they participate in hostilities, they lose their protection.[39] If they fall into the enemy's hands, they are not considered prisoners of war and must be set free.[40]Since they use the distinctive sign of the red cross, red crescent, or red crystal to guarantee their special protection, they were visible to the enemy's forces. Attacking them is a war crime under article 8(2) lit. b(xxiv) and 8(2) lit. e(ii) Rome Statute.[41]

2. Cultural Property edit

Cultural property enjoys special protection in armed conflicts.[42] The two additional protocols contain provisions specifically protecting for cultural property in IAC and NIAC. Additionally, the Hague Convention for the protection of cultural property in the event of armed conflict from 1954 and its two protocols complement the protection based on the Geneva law.[43] Cultural property is protected in armed conflcits because of its relevance for humanity and because everyone contributes to the world's culture.[44] Destruction of cultural heritage can amount to a war crime under the Rome Statute.[45]

3. Natural Environment edit

The environment has been called a "silent victim" of war.[46] Only since the aftermath of the Vietnam War and with the adoption of AP I, the "natural environment" enjoys direct protection from "widespread, long-term and severe damage" in IACs.[47] However, it is unclear whether ‘long-term’ is measured in years or decades; based on the travaux préparatoires (French: ‘preparatory work’) the latter seems to be the case.[48] Most scholars assume that this was not even reached in the cases of the Vietnam War and the deployment of Agent Orange, or when burning oil wells in Kuwait in 1991. Additionally, elements of the environment are protected as civilian objects.[49] They rarely serve military purposes and hence only rarely represent a military objective that can be attacked lawfully. Moreover, other provisions indirectly protect the environment, such as article 56 AP I on installations containing dangerous forces as nuclear power plants or dams.

II. New technologies edit

1. Semi-Autonomous Weapons edit

Warfare technologies have made unprecedented strides in the last few decades. Such a development provides a strategic and operational edge, while it also raises numerous legal questions concerning the principles of distinction, necessity, proportionality, and so forth. In theory, semi-autonomous weapons like combat drones are more precise and proportionate. This is why combat drones were presented as 'the weapon of choice' at the start of the 'War on Terror' .[50] Where the results on saving the lives of drone operators are certainly positive, the loss of lives when targeting the alleged terrorists are in many cases not proportionate to the actual security threat they pose. For instance, in case of the US drone attacks against terrorists in Pakistan, Yemen, and Somalia, various governmental and non-governmental studies point to the fact that in contrast to their technological reputation for precision, combat drones are not that much precise, operationally.[51] Nonetheless, the US remains adamant that the combat drones are precise and avoid losses to the innocent lives, despite the discrepancies surrounding the loss of innocent civilian lives. Undoubtedly, in some instances, combat drones pinpointed and eliminated the terrorists with more precision than conventional weapons, [52] complying with 'all feasible precautions' before striking down the intended target, and adequately fulfilling the principles of military necessity and proportionality. Notwithstanding the technological sophistication of combat drones and their ability to be precise and proportionate, their past deployment, specifically against the belligerent non-State actors, raises some serious questions about the fulfilment of humanitarian principles. The actual practices of the usage of combat drones seriously question their precision and proportionality, as often described in theory.[53]

2. Autonomous Weapons edit

Within the context of the weapons of warfare, autonomy is a relative term. It may range and encompass launching a weapon to the point of successfully selecting, engaging, and neutralising the target.[54] According to the United States Department of Defense, a weapons system is autonomous when 'once activated, (it) can select and engage targets without further intervention by a human operator'.[55] In contrast, humans remain in the loop with semi-autonomous weapons when deciding and targeting enemy combatants. In general, artificial intelligence and autonomous weapons challenges the cardinal principles, such as humanity and proportionality. For instance, Articles 51 and 57 of AP I stress the importance of avoiding excessive physical and material damages in warfare. [56] Avoidance of excessive damage in terms of the autonomous weapons depends upon the efficient decision-making. However, autonomous weapons based on data feeds reach decisions within moments, and thus might undermine the role of human judgement.[57] Moreover, since the algorithm is based on image classifications such as soldier uniforms, insignias, numerous types of rifles and ammunitions, it can be hacked and fed with different image classifications. In other cases, images can be misinterpreted by autonomous weapons.[58] Despite ethical, legal, and political questions[59] about the nature of and about certain characteristics of autonomous weapons challenging the cardinal principles, they may better protect a State's military personnel.[60]

3. Cyber Weapons edit

Cyber[61] weapons, such as spyware and malicious software codes, have already brought down down the governmental digital platforms in Estonia and destroyed certain nuclear reactors in Iran, raising questions of armed attacks in jus ad bellum, possibly triggering the right to self-defence under article 51 UN Charter, and State responsibility. With regard to the jus in bello, the cardinal principles of the law of armed conflict are challenged.[62] In one scenario, due to the easiness and less costly prospects, a military commander might decide to shut down an electricity grid by a cyber attack to disrupt the command and communication structures of a nearby military installation, possibly violating the principle of distinction and proportionality. In cyber warfare, like in conventional warfare, there are high chance of indirectly targeting civilian cyber infrastructure. [63]

G. Interplay with Other Fields of Public International Law edit

Decades ago, the law of war represented the lex specialis (Latin: 'special law') in war-related matters.[64] With the adoption of the 1949 Geneva Conventions and the 'humanisation' of the law of war, there is agreement today among States and scholars that human rights[65] can complement the law of war under certain conditions, particularly based on non-derogable human rights such as the right to life. In turn, regional and universal human rights systems as well as the International Court of Justice have clarified questions at the intersection of human rights law and the law of war in the past decade.[66] In 1996, the International Court of Justice in the advisory opinion on the Legality of the Threat or Use of Nuclear Weapons stated that

[. . .] the protection of the International Covenant of Civil and Political Rights does not cease in times of war, except by operation of Article 4 of the Covenant whereby certain provisions may be derogated from in a time of national emergency. Respect for the right to life is not, however, such a provision. In principle, the right not arbitrarily to be deprived of one’s life applies also in hostilities. The test of what is an arbitrary deprivation of life, however, then falls to be determined by the applicable lex specialis, namely, the law applicable in armed conflict which is designed to regulate the conduct of hostilities."[67]

In 2005, it specified the interplay in the Wall Advisory Opinion by stating that "[a]s regards the relationship between international humanitarian law and human rights law, there are thus three possible situations: some rights may be exclusively matters of international humanitarian law; others may be exclusively matters of human rights law; yet others may be matters of both these branches of international law."[68]

Other fields also co-exist or apply simultaneously to the law of war. The UN International Law Commission in its work on "The Effects of Armed Conflict on Treaties" in 2011 confirmed that certain treaties continue to "in operation" during an armed conflict.[69] In an annex, the Commission included a list of treaties[70] that presumingly continue to apply during armed conflict to the draft principles, these include treaties like international environmental law,[71] and are not suspended in case of an armed conflict.[72]

International criminal law is another field of public international law that complements the law of war. In the Rome Statute, States have codified and criminalised war crimes that are conducted during hostilities, thus relating to the law of war. However, the Office of the Prosecutor of the International Criminal Court can only investigate crimes as agreed upon in the Rome Statute, thus separating the law of war from international criminal law and resulting in differing legal standards.

H. Conclusion edit

The law of armed conflict is built around the tensions between military force on the one hand, and humanitarian considerations on the other. It regulates (and facilitates) the conduct of hostilities, while it also intends to spare civilians and the civilian population from the consequences of warfare, despite a prohibition of aggression under the jus ad bellum. The 1899/1907 Hague Regulations, the 1949 Geneva Conventions and their additional protocols, together with customary rules and the cardinal principles of the law of armed conflict determine the legality of today’s warfare. Only when the cardinal principles together with the specific regulations are complied with, then a belligerent party can launch a lawful attack against a target. These rules and principles apply to conventional warfare as well as to new technologies; they protect the civilian population, civilian objects, and protected groups and objects alike.

Further Readings edit

Further Resources edit

Summary edit

  • This chapter sums up the primary norms, rules, actors, and subjects of the law of armed conflict.
  • Also, it extrapolates the ways in which the modern tools of warfare like semi-autonomous and autonomous weapons, cyber weapons, potentially, challenge the existent rules governing the conduct of hostilities in armed conflicts. Moreover, it explains how specific protected groups and object are protected in war.

Table of Contents edit

Back to home page

Part I - History, Theory, and Methods

Part II - General International Law

Part III - Specialized Fields

Footnotes edit

  2. Marco Sassòli, Antoine Bouvier and Anne Quintin, How Does Law Protect in War? Cases, Documents and Teaching Materials on Contemporary Practice in International Humanitarian Law (Vol. I, 3rd ed, ICRC Publications 2011) 1.
  3. On jus ad bellum, see Svicevic, § 13, in this textbook. {{cite book}}: Missing or empty |title= (help)CS1 maint: multiple names: authors list (link)
  4. Charter of the United Nations (1945), XV UNCIO 335.
  5. Dunant, A Memory of Solferino, available at
  6. Fought between the French troops, allied to the Sardinians, and the Austrians troops on June 24, 1859, the battle of Solferino left 6,000 dead and 40,000 wounded on the very first day. The sufferings of unattended wounded as observed by Henry Dunant gave way to the formation of the Red Cross. For details, 'The battle of Solferino' (1859) <> accessed 23 June 2022
  7. Janne Elisabeth Nijman, "Bertha von Suttner: Locating International Law in Novel and Salon," in: Immi Tallgren, Portraits of Women in International Law - New Names and Forgotten Faces?, OUP 2022.
  8. Frits Kalshoven and Liesbeth Zegveld, Constraints on the Waging of War: An Introduction to International Humanitarian Law (ICRC Publications 2001) 27-29.
  9. See ICRC, Commentary GC I, pp 81–82 para. 224, available at; D. Akande, Classification of Armed Conflicts: Relevant Legal Concepts, in: E. Wilmshurst (ed.), International Law and the Classification of Conflicts (OUP, 2012), pp 32–79; J. K. Kleffner, Scope of Application of International Humanitarian Law, in: Fleck (ed.), Handbook of International Humanitarian Law, 4th ed., 2021, p. 52, para. 3
  10. On customary law, see Stoica, § 6, Section 2, in this textbook.
  11. On the variety of actors, see Engström, § 7, in this textbook.
  12. Geneva Academy, ‘Rule of Law in Armed Conficts (RULAC)’ accessed 26 June 2022.
  13. Kalshoven and Zegveld (n 7) 15.
  14. The ICRC has conducted a study on customary IHL in 2005 and since then regularly updates the analysis of state practice and opinio juris. It is available online at
  15. ICRC. "Fundamental principles of IHL". Retrieved 26 June 2022.
  16. 'Lieber Code: Instructions for the Government of Armies of the United States in the Field' (24 April 1863) <> accessed 24 June 2022
  17. 'Convention (I) for the Amelioration of the Condition of the Wounded and Sick in Armed Forces in the Field' (12 August 1949) <> accessed 25 June 2022
  18. 'Protocol Additional to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of International Armed Conflicts (Protocol I) (8 June 1977) <> accessed 26 June 2022
  19. For a detailed treatment of this principle as a customary norm, Jean-Marie Henckaerts and Louise Doswald-Beck, Customary International Humanitarian Law (Vol. I, CUP 2005) 306-343.
  20. Legality of the Threat or Use of Nuclear Weapons (n 10) para 78, 92.
  21. Henckaerts and Doswald-Beck (n 16) 3.
  22. 'Convention (IV) respecting the Laws and Customs of War on Land and its annex: Regulations concerning the Laws and Customs of War on Land' (18 October 1907) The Hague <> accessed 26 June 2022
  23. 'Protocol Additional to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of Non-International Armed Conflicts (Protocol II)' (8 June 1977) <> accessed 25 June 2022
  24. ICRC. "Military necessity". Retrieved 26 June 2022.
  25. 'Convention (IV) respecting the Laws and Customs of War on Land and its annex: Regulations concerning the Laws and Customs of War on Land' (18 October 1907) The Hague <> accessed 27 June 2022
  26. ICRC. "Proportionality". Retrieved 26 June 2022.
  27. Henckaerts and Doswald-Beck (n 16) 49-51.
  28. 'Convention (IX) concerning Bombardment by Naval Forces in Time of War' (18 October 1907) The Hague <> accessed 28 June 2022
  29. On States, see Green, § 7, Section 1, in this textbook.
  30. Cf. conclusion 7 and its commentary of the ILC’s draft conclusions on subsequent agreements and subsequent practice in relation to the interpretation of treaties with commentaries, available at (accessed 16 March 2024).
  31. Cf. conclusion 4, para 4 of the ILC’s draft conclusions on the identification of customary international law with commentaries, available at (last accessed 16 March 2024).
  32. Annyssa Bellal and Stuart Casey-Maslen, ‘Enhancing Compliance with International Law by Armed Non-State Actors’ (2011) 3(1) GoJIL 175–197.
  33. ICRC blog, What is the ICRC's role in developing and ensuring respect for IHL?, available at
  34. On the variety of actors, see Engström, § 7, in this textbook.
  35. See ICRC, Research Guide ‘The Fundamental Principles of the International Red Cross and Red Crescent Movement’, available at accessed 23 June 2022.
  36. For IACs, see articles 24-25 GC I, articles 36-27 GC II, and article 15 AP I; for NIAC, see article 9 AP II.
  37. See articles 24-25 GC I, articles 36-37 GC II, articles 15-16 AP I.
  38. See, e.g, The Practical Guide to Humanitarian Law 'Medical Personal' (Médécins Sans Frontiéres) < (last accessed 15 March 2022).
  39. See articles 24-25 GC I, articles 36-37 GC II, and article 15-16 AP I.
  40. See e.g. Articles 28-32 GC I.
  41. On international crimes, see Fiskatoris, § 22, Section 1, in this textbook.
  42. See generally, O'Keefe, Roger, The Protection of Cultural Property in Armed Conflict (CUP 2006).
  43. See article 53 AP I and article 16 AP II. Cultural property also enjoys protection under customary law, see ICRC, 'Study on Customary IHL,' Chapter 12, Rules 38-41, available at accessed 15 March 2022).
  44. Preamble of the 1954 Hague Convention.
  45. See e.g. the Al Mahdi Case by the ICC, The Prosecutor v. Ahmad Al Faqi Al Mahdi, ICC-01/12-01/15, more information available at (last accessed 15 March 2022).
  46. UN Environment Programme, 'Rooting for the Environment in Times of Conflict and War,' (UNEP Press release, 6 November 2019) available at (last accessed 15 March 2022)
  47. See articles 35(3) and 55(1) AP I; for custom, see rules 43–45 in ICRC, ‘Study on Customary IHL,’ Chapter 14 accessed 15 March 2022.
  48. See Anne Dienelt, Armed Conficts and the Environment: Complementing the Laws of Armed Confict with Human Rights Law and International Environmental Law (Springer 2022) 57 ff.
  49. See Cordula Droege and Marie-Louise Tougas, ‘The Protection of the Natural Environment in Armed Confict – Existing Rules and Need for Further Legal Protection’ (2013) 82(1) Nordic Journal of International Law 21, 23.
  50. Remarks of Director of Central Intelligence Agency, Leon E. Panetta, at the Pacific Council on International Policy (May 18, 2009) <> accessed 23 July 2022
  51. 'Living under Drones: Death, Injury and Trauma to Civilians from US Drone Practice in Pakistan (International Human Rights and Conflict Resolution Clinic, Stanford Law School and Global Justice Clinic, New York University School of Law 2012); Jo Becker and Scott Shane, 'Secret "Kill List" Proves a Test of Obama’s Principles and Will,' The New York Times (29 May 2012) A1; Letta Tayler, 'Between a Drone and Al-Qaeda: The Civilian Cost of US Targeted Killing in Yemen,' (New York, Human Rights Watch 2013); Jane Mayer, 'The Predator War: What are the Risks of the C.I.A.’s Covert Drone Program?' The New Yorker (26 October 2009); 'Daily Situation Report,' (FATA Secretariat, Ministry of Interior, Pakistan, 2007-2017; Ben Emmerson, 'Report of the Special Rapporteur on the Promotion and Protection of Human Rights and Fundamental Freedoms While Countering Terrorism,' UN Document A/68/389 (18 September 2013); Philip Alston, 'Report of the Special Rapporteur on extrajudicial, summary or arbitrary executions,' (presented to the Human Rights Council, 14th session, 28 May 2010).
  52. Imdad Ullah, Terrorism and the US Drone Attacks in Pakistan: Killing First (Routledge 2021) 131.
  53. Hugh Gusterson, Drone: Remote Control Warfare (The MIT Press 2016); 'Civilian Casualties & Collateral Damage,' (n 46); Letta Tayler, 'Between a Drone and Al-Qaeda: The Civilian Cost of US Targeted Killing in Yemen,' (Human Rights Watch 2013) <> accessed 23 July 2022; 'A Wedding That Became a Funeral,' (Human Rights Watch 2014); 'France's Shadow War in Mali: Airstrikes at the Bounti Wedding,' (Stoke White Investigations 2021) <> accessed 24 July 2022
  54. For a detailed treatment of autonomy in autonomous weapons systems and how may it operate in warfare, see Kenneth Payne, 'Artificial Intelligence: Artificial Intelligence: A Revolution in Strategic Affairs?' (2018) 60 Survival 7-32; Giovanni Sartor and Andrea Omicini, 'The autonomy of technological systems and responsibilities for their use' in Nehal Bhutta and others (eds), Autonomous Weapons Systems: Law, Ethics, Policy (CUP 2016) 40-65.
  55. 'Autonomy in Weapons Systems' U.S. Department of Defense, directive no. 3000.09 (21 November 2012)
  56. Dan Saxon, 'A Human Touch: Autonomous Weapons, Directive 3000.09, and the "Appropriate Levels of Human Judgment over the Use of Force" (Summer/Fall 2014) 15/2 Georgetown Journal of International Affairs 103. For further details, see Bill Boothby, 'How Far Will the Law Allow Unmanned Targeting to Go?' in Dan Saxon (ed), International Humanitarian Law and the Changing Technology of War (Mārtiņus Nijhoff/Brill 2013) 62-63; and David Akerson, 'The Illegality of Offensive Lethal Autonomy' in Dan Saxon (ed), International Humanitarian Law and the Changing Technology of War (Mārtiņus Nijhoff/Brill 2013) 7I.
  57. Michael T. Klare, 'Autonomous Weapons Systems and the Laws of War' (2019) 49 Arms Control Today 6-12.
  58. ibid.
  59. For details of such voices, Mary E. O’Connell, 'Banning Autonomous Killing—The Legal and Ethical Requirement That Humans Make Near- Time Lethal Decisions' in Matthew Evangelista and Henry Shue (eds), The American Way of Bombing: Changing Ethical and Legal Norms From Flying Fortresses to Drones (Cornell University Press 2014) 224-235; Rebecca Crootof, 'A Meaningful Floor For "Meaningful Human Control" (2016) 30 Temple International and Comparative Law Journal 53–62; Peter Asaro, 'Jus nascendi, Robotic Weapons and the Martens Clause' in Ryan Calo, Michael Froomkin and Ian Kerr (eds), Robot Law (Edward Elgar Publishing 2016) 367–386.
  60. Duncan Macintosh, 'Fire and Forget: A Moral Defense of the Use of Autonomous Weapons Systems in War and Peace' in Duncan Macintosh and Jens D. Ohlin (eds), Lethal Autonomous Weapons: Re- Examining the Law and Ethics of Robotic Warfare (OUP 2021) 9-23.
  61. On international law in cyberspace, see Hüsch, § 19, in this textbook.
  62. 'International Humanitarian Law and the Challenges of Contemporary Armed Conflicts' (October 2015) ICRC, 16.
  63. Michael N. Schmitt, Tallinn Manual 2.0 on the International Law Applicable to Cyber Operations (CUP 2017) 348-50.
  64. See e.g. Chapter 14 in: Fleck (ed.), The Handbook of International Humanitarian Law, 4th ed, CUP 2021.
  65. On international human rights law, see Ciampi, §21, in this textbook.
  66. See e.g. IACommHR, Coard et Al. v. United States; IACommHR, Victor Saldaño v. Argentina; Report of the Special Rapporteur on the Situation of Human Rights in Occupied Kuwait, 50–54, UN Doc. E/CN.4/1992/26 from 16 January 1992.
  67. ICJ, Advisory opinion on the Legality of the Threat or Use of Nuclear Weapons, §25.
  68. ICJ, Advisory opinion on the Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory, §106.
  69. See draft article 7, ILC, ‘Draft Articles on the Efects of Armed Conficts on Treaties’ (2011) UN Doc. A/66/10, paras 100–101.
  70. On international treaties, see Fiskatoris and Svicevic, § 6, Section 1, in this textbook.
  71. See, e.g., Dienelt (n 48) 234 f. On international environmental law, see Poorhashemi, § 16, in this textbook.
  72. On multilateral environmental treaties and armed conflict, see. e.g. Sjöstedt,"The role of multilateral environmental agreements in armed conflict: ‘Green-keeping’in Virunga Park. Applying the UNESCO World Heritage Convention in the armed conflict of the Democratic Republic of the Congo," Nordic Journal of International Law 82.1 (2013), pp 129-153.