6.4: Means and Methods of Warfare

Apart from providing protection for civilians and other categories of protected persons during armed conflict, IHL also regulates the means used to conduct hostilities (means of warfare) and the way in which hostilities are conducted (methods of warfare). These matters are now subjected to three basic rules codified in Article 35 of Protocol I. This provision determines that (a) the right of the parties to an armed conflict to choose the means or methods of warfare is not unlimited; (b) it is prohibited to employ weapons and methods of warfare that would cause superfluous injury or unnecessary suffering; and (c) it is prohibited to employ means and methods of warfare which are intended, or may be expected, to cause widespread, long-term and severe damage to the natural environment. In view of these restrictions states parties are under an obligation, when developing, acquiring or adopting new weapons, to determine whether such weapons will be prohibited by this Protocol (Article 36).

Under these rules the use of certain weapons will be prohibited in all circumstances because of their inherent characteristics and indiscriminate effects, in other instances the use of a certain weapon could be merely limited or restricted. To the first category belongs the use of expanding bullets, blinding laser weapons, poisonous gases, biological and chemical weapons, anti-personnel mines and cluster munitions.^[3] Viewed as being contrary to considerations of humanity the use of these weapons has over time become outlawed by means of specific multilateral treaty arrangements with the result that their use will constitute a war crime under current international criminal law. To the second category belong restrictions on the use of certain conventional weapons now governed by a series of Protocols annexed to the 1980 Convention on Prohibitions and Restrictions on the Use of Certain Conventional Weapons.

A case of a special kind is presented by nuclear weapons. That this is by definition a kind of weapon that would certainly fall foul of the object and purpose of Article 35 should not be in dispute. In 1996, the International Court of Justice rendered an advisory opinion in the famous Nuclear Weapons case on the question—submitted to the Court by the General Assembly of the United Nations—whether the threat or use of nuclear weapons can in any circumstances be permitted under international law. In its analysis of international humanitarian law and principles the Court concluded that the “principles and rules applicable in armed conflict—at the heart of which is the overriding consideration of humanity—make the conduct of armed hostilities subject to a number of strict requirements.” Following this logic, the Court then reasoned that “methods and means of warfare, which would preclude any distinction between civilian and military targets, or which would result in unnecessary suffering to combatants, are prohibited.” Consequently, because of the “unique characteristics of nuclear weapons … the use of such weapons in fact seems scarcely reconcilable with respect for such requirements” (ICJ Reports 226, 1996, para. 95). However, in the final analysis, the Court, having considered what it called the “present state of international law,” reached the conclusion (by the casting vote of the President of the Court!) that it could not reach a definitive conclusion as to the legality or not of the use of nuclear weapons by a state “in an extreme circumstance of self-defence, in which its very survival would be at stake” (para. 97). In instances not involving this extreme position the Court was unanimous in its opinion that the threat or use of nuclear weapons should also be compatible with the requirements of international law applicable in armed conflict, particularly “those of the principles and rules of international humanitarian law …” (para. 97D).

Another issue under this theme is the increasing development and potential use by a growing number of states of ‘lethal autonomous weapon systems,’ which refers to weapon systems that function without meaningful human control over the critical functions of selecting and detecting individual targets. Because of the human rights and international humanitarian law implications of the use of such weapon systems, among others, the matter has featured for some time on the agenda of the UN Human Rights Council and other UN Bodies (see for instance UN Human Rights Council Documents A/HRC/23/47 of 9 April 2013 and A/HRC/26/36 of 1 April 2014) and has attracted volumes of scholarly contributions in recent times on the legal, moral and ethical implications of the use of such weapons with some calling for an outright international ban on such weapon systems.

On 12 September 2018, the European Parliament adopted a resolution (2018/27529RSP) calling on member states and the European Council to adopt as a matter of urgency a common position on lethal autonomous weapon systems that ensures meaningful human control over the critical functions of such systems. The resolution also raised concerns that the development of these weapon systems could prompt an unprecedented and uncontrolled arms race and about the implications of their use for key questions of international human rights and international humanitarian law. In response to this resolution a report was published in November 2018 indicating that there is an emerging consensus between European states that meaningful human control over the use of force should be retained, especially with regard to critical functions such as selecting and attacking targets, that human control is a prerequisite for compliance with international humanitarian law and as a way of ensuring accountability. ^[4]

When we speak about methods of warfare we have in mind certain tactical or strategic considerations meant to outweigh or weaken the enemy. In this case too, the methods of warfare are not unlimited and methods causing unnecessary suffering or superfluous injury will be prohibited. It is now well established that the following are forbidden: giving or ordering no quarter, pillaging, perfidious conduct (misuse of a flag of truce or other protected emblem) and starvation of civilians.