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Means and Methods of Warfare

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The parties to an armed conflict are limited in their choice of weapons and means and methods of warfare under the rules of international humanitarian law (IHL).1Article 22 of the 1907 Hague Regulations Respecting the Laws and Customs of War on Land and Article 35(1) of Additional Protocol I to the Geneva Conventions of 1949 The principle of humanity dictates that it is prohibited to employ weapons and tactics which can cause superfluous injuries and unnecessary suffering. 2Article 35 (1) and (2) of the 1977 Additional Protocol I The military must also not use a weapon or method of warfare when humanitarian considerations outweigh its military necessity. Furthermore, as per the Martens Clause, particularly abhorrent weapons, according to the dictates of established custom, humanity and public conscience, cannot be used, even if no specific prohibition exists.3The Preamble to Hague Convention (IV) Respecting the Laws and Customs of War on Land contains the provisions of the Martens Clause

Treaties and customary rules have developed over time which prohibit the use of certain weapons, including biological and chemical weapons, anti-personnel mines, and blinding laser weapons. These have been significant milestones in regulating the conduct of hostilities. However, whilst there has been much development in this area of law, key difficulties remain particularly with regards to the language used in these norms, national reviews of the legality of weapons, and the application of these norms to non-international armed conflicts. The ways in which these rules and prohibitions would apply to emerging new weapons technologies is not always clear. This clarity is particularly necessary given the potential future military use of weapons such as directed energy, incapacitants, behaviour change agents, and nanotechnology.4Lawand, Kathleen. “Reviewing the legality of new weapons, means and methods of warfare.” International Review of the Red Cross, vol. 88, no. 864, December 2006, p. 925-930, page 925

These issues are discussed in this editorial as an introduction to this month’s articles on means and methods of warfare. The other articles on the Diplomacy, Law, and Policy Forum relating to this theme focus on prohibited means and methods, the regulation of cyberwarfare, and autonomous weapons systems. The underlying question being whether IHL can keep up with rapid advances in technology.

Defining Superfluous Injury or Unnecessary Suffering

In the Nuclear Weapons Advisory Opinion, the International Court of Justice held that the prohibition on weapons and methods of warfare which caused superfluous injury or unnecessary suffering was one of the “intransgressible principles of international customary law”.5Nuclear Weapons Advisory Opinion, 1996 I.C.J. 226, 179. 39. The Court established a two-part test in order to determine the legality of weapons; namely, whether there was a specific prohibition in international law as to the threat or use of the weapon; and failing that whether there was a general prohibition of the threat or use of the weapon.6Ibid at 52-57 and 58-63 The meaning of the terms themselves though remains unclear and undefined and for that reason, it is difficult to decide whether a weapon is to be deemed unlawful owing to its ability to cause superfluous injury or unnecessary suffering where no specific or general prohibition exists. Indeed, the fact that unnecessary suffering is prohibited in the laws of war indicates that there is such a thing as lawful, necessary suffering.7Parks, W. Hays. “Means and Methods of Warfare.” George Washington International Law Review, vol. 38, no. 3, 2006, p. 511-542. Page 534

In 1997, the International Committee for the Red Cross (ICRC) began a project known as the Superfluous Injury or Unnecessary Suffering (SIrUS) Project which aimed to establish objective criteria to determine whether a weapon causes these effects.8Library of Congress, Military Legal Resources, The SIrUS Project: Towards a determination of which weapons cause “superfluous injury or unnecessary suffering” Robin M. Coupland, Editor, Geneva, International Committee of the Red Cross, 1997 It collected data on the war-wounded from ICRC’s field hospital database to quantify mortality rates and permanent injury rates.9Fry, James D. “Contextualized Legal Reviews for the Methods and Means of Warfare: Cave Combat and International Humanitarian Law.” Columbia Journal of Transnational Law, vol. 44, no. 2, 2006, p. 453-519. page 484 The methodology was called ‘well-intentioned, but flawed’ in that it actually measures what are normal or routine wounds from battle – i.e. not superfluous injury or unnecessary suffering.10Supra n.8 and n.9 Growing opposition led to the withdrawal of the project in 2001.11Ibid As a result, there is still little by way of clarity in how these terms are to be defined. Drawing the line between necessary and unnecessary is difficult and an endeavour for which IHL offers little by way of clarity.

Article 36 of Additional Protocol I

States party to Additional Protocol I are obliged to determine whether the use of a weapon, means, or method of warfare that it studies, develops, acquires or adopts would, in some or all circumstances, be prohibited by international law applicable to the State. This provision was rather revolutionary in that it affirmed and countered the traditional view that determinations on the legality of weapons was to be left to the prerogative of states.12Supra n.7, page 514 Whilst it was still a matter for States, they were now obligated to undertake such a review and ensure the legality of the weapon.

Article 36 seeks to ensure that the development and use of cruel and indiscriminate weapons is prevented in order to respect the principle of humanity.13Supra n.4, page 929 and Supra n.9, page 468 It requires states to incorporate national mechanisms and procedures to review the legality of new weapons and reassess the use of existing weapons they possess in their stockpile as new norms of international law are established.14Supra n.4 page 925 This mechanism should involve both a permanent procedure which is activated when a state is developing or acquiring a new weapon and also an obligation by law or administrative directive that it be mandatory for the authority responsible for this development or acquisition to follow this procedure.15Ibid The provision is complemented by Article 82 of Additional Protocol I which requires legal advisers to be available at all times to advise commanders on the appropriate instructions to be given to the armed forces on the subject.
In the 28th International Conference of the Red Cross and Red Crescent in 2003 it was declared that “[i]n light of the rapid development of weapons technology and in order to protect civilians from the indiscriminate effects of weapons and combatants from unnecessary suffering and prohibited weapons, all new weapons, means and methods of warfare should be subject to rigorous and multidisciplinary review.”16Final Goal 2.5 of the Agenda for Humanitarian Action adopted by the 28th International Conference of the Red Cross and Red Crescent (2003) However, despite this obligation, not enough states party to Additional Protocol I have adopted formal weapons review procedures.17Supra n.4 page 926 In 2006, the ICRC formulated ‘A Guide to the Legal Review of New Weapons, Means and Methods of Warfare’ in order to assist states in adopting a review mechanism.18“A Guide to the Legal Review of New Weapons, Means and Methods of Warfare: Measures to Implement Article 36 of Additional Protocol I of 1977 International Committee of the Red Cross Geneva, January 2006.” International Review of the Red Cross, vol. 88, no. 864, December 2006, p. 931-956. It emphasises that a new weapon (i.e. a means of warfare) cannot be isolated from the way it is to be used (i.e. the method of warfare).
Lawand argues that the wording of Article 36 (particularly the use of “in some or all circumstances) obliges the reviewing authority to not only consider the proposed or intended effects of the weapon but also other foreseeable uses and effects.19Supra n.4 The Commentary on the Additional Protocols however does clarify that the state is “not required to foresee or analyse all possible misuses of a weapon”.20Y. Sandoz, C. Swinarski, B. Zimmerman (eds.), Commentary on the Additional Protocols o f8 June 1977 to the Geneva Conventions of 12 August 1949, ICRC, Geneva, 1987, paragraph 1469 This would make sense as even a handgun could be misused to murder an innocent civilian, however, its misuse would not render an otherwise lawful weapon, illegal.21Supra n.7 footnote 25 If some expected ways of using the weapon are found to be unlawful then restrictions ought to be placed on the weapon’s use and incorporated into its operating procedures.22Supra n.4 page 929 Furthermore, all cardinal principles of IHL are to be considered when determining the legality of a weapon, for instance, with the principle of precaution, it is necessary to ascertain whether the weapon allows for cancellation of an attack in the event that the target is not a military objective.23Ibid
The issue with national reviews under Article 36 is that as there remains little guidance as to the type of review that States should conduct, determinations across national systems are inconsistent. For instance, Germany considers shotguns and tear gas to be unlawful means of warfare whereas the United States deems these to be legal.24Supra n.9, page 488 This inconsistency has led to calls for an independent body or for the ICRC to step in and facilitate such reviews.

The Role of the ICRC

The International Committee of the Red Cross obtained a mandate at the 22nd International Conference of the Red Cross in 1973 to consider the question of conventional weapons.25Supra n.7, page 514 However, some states have argued that the legality of weapons is an issue of arms control and therefore better handled by the United Nations’ Committee on Disarmament.26Ibid The ICRC’s role was questioned within and outside the organisation; those within believed that it possessed neither the expertise nor experience with weapons and pursuing issues regarding their legality would detract from its humanitarian role.27Ibid Others believed that the ICRC should not be seen as challenging any weapons as it may be considered as a ‘seal of approval’ on weapons that were not so challenged.28Ibid Others still believed the ICRC was well suited to such a role. During the negotiations of the Additional Protocols, Pakistan supported an amendment which would put weapon review under the mandate of the ICRC, despite some states seeing this as the organisation straying too far into disarmament.29Supra n.9 490 Nonetheless, the negotiations to prohibit certain conventional weapons were fruitful, culminating in treaties which banned the use of certain weapons such as mines and even non-existent weapons such as blinding lasers which would have had untold effects on civilians and caused human suffering. Furthermore, the ICRC reportedly does play a consultative role for states when they are conducting Article 36 reviews though it is not clear what form these consultations take.30Ibid

Non-International Armed Conflicts

There are very few treaties in IHL which are applicable to non-international armed conflicts (NIACs) and most that do are concerned more with the protection of victims than the means and methods of warfare.31Turns, David. “At the Vanishing Point of International Humanitarian Law: Methods and Means of Warfare in Non-International Armed Conflicts.” German Yearbook of International Law, 45, 2002, p. 115-148. Page 120 This may become increasingly problematic as, Turns notes, “in modern times the frequency, ferocity, cruelty, and intensity of internal armed conflicts have been remarkable”.32Ibid Moreover, even the customary norms applicable to NIACs may not always apply to non-state actors which are typically one of the parties to civil strife.33Ibid Some attempts were made to rectify this in 2001 during the Second Review Conference for the 1980 UN 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 (CCW).34United Nations, 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 (and Protocols) (As Amended on 21 December 2001), 10 October 1980, 1342 UNTS 137 The application of the Convention and its Protocols were extended to non-international armed conflicts. However, it does not extend to all future Protocols which will have to be negotiated afresh to determine whether they apply to internal conflict.35Supra n.31, page 130
Despite this extension in application, there remain some gaps in enforcement of such norms in international criminal law to NIACs.36Ibid. page 147 Under the Rome Statute three categories of weapons are criminalised in both IACs and NIACs; namely, poison or poisoned weapons, chemical weapons, and dumdum bullets. However, only in IACs are “weapons, projectiles and material and methods of warfare which are of a nature to cause superfluous injury or unnecessary suffering or which are inherently indiscriminate” prohibited.37See Article 8(2)(b)(xvii-xx) and compare with Article 8(2)(e)(xiii-xv), UN General Assembly, Rome Statute of the International Criminal Court (last amended 2010), 17 July 1998 There is no similar criminalisation for NIACs. Whilst it is clear that the process of assimilation between IAC and NIAC law is ongoing, it is hoped that these gaps are filled in order to ensure that accountability is not escaped merely as a result of classification.38Supra n.31, page 147


IHL contains restrictions and prohibitions on means and methods of warfare in accordance with the principles of limitation and humanity. Given technological advances, it is likely that more rules and norms will be required in the future as States hasten to incorporate ever-improving weapons into their military arsenal. As a result, it is necessary that such means and methods of warfare be deemed lawful or unlawful through precise legal language and through national mechanisms which are rigorous, transparent, and consistent across jurisdictions. Moreover, any emerging norms should also apply to non-international armed conflicts; as their frequency and ferocity increases, so does the need to protect civilians caught up in civil strife. It is important to remember the words of Henry Dunant when he stated that “[i]f the new and frightful weapons of destruction which are now at the disposal of the nations seem destined to abridge the duration of future wars, it appears likely, on the other hand, that future battles will only become more and more murderous”, and ensure that this does not happen.39Henry Dunant, Memory of Solferino, 1862