On Law, Cake and Booby-Traps: A Reply to Dr Lucas Roorda

[Dr Aurel Sari is a Professor of Public International Law at the University of Exeter and Fellow at Supreme Headquarters Allied Powers Europe]

Last week, Dr Lucas Roorda published a thoughtful post on this site about the interpretation of Article 7(2) of Amended Protocol II to the Convention on Certain Conventional Weapons (APII CCW). Amended Protocol II imposes certain restrictions on the use of mines, booby-traps and certain other devices in the context of international and non-international armed conflicts. The scope of these restrictions has become the subject of debate in the wake of the pager attack carried out against Hezbollah on 17 September 2024. The attack saw the explosion of approximately 3,000 old-school communication devices, pagers, used by Hezbollah. The incident has widely been attributed to Israel, although it has not been officially acknowledged as an Israeli operation. A similar attack took place on 18 September 2024, this time involving walkie-talkies. 

Israel is a party to APII CCW and as such is bound by its provisions. Provided that the Convention applies to the conflict between Israel and Hezbollah, and assuming that the pager attack was carried out by Israel, the question arises whether it was compatible with the provisions of APII CCW. These include Article 7(2) APII CCW, which reads as follows: 

It is prohibited to use booby-traps or other devices in the form of apparently harmless portable objects which are specifically designed and constructed to contain explosive material.

In an exchange on social media, I have taken the position that Article 7(2) APII CCW applies to the pagers only if they were objects specifically created to contain explosive material, in other words only if they were custom-made, but not if they were pre-existing objects adapted to explode as a result of subsequent modifications.

Dr Roorda has dismissed this interpretation as unpersuasive, arguing that it runs counter to other provisions of APII CCW, distorts the practice of using booby-traps and is at odds with the underlying principles of the law of armed conflict. In this reply, I attempt to explain why this is not the case. 

Splitting Hairs and Playing Games?

Before turning to the law, some preliminary remarks are in order. I agree with Dr Roorda that a disagreement over the interpretation of Article 7(2) APII CCW may not be the most pressing problem when seen against the background of the horrors unfolding in the Middle East. Indeed, compared to the scale of human suffering and destruction, bickering over some obscure rule may seem not just trivial, but obscene: how can we split legal hairs when countless lives and elementary considerations of morality are at stake? On one level, the frustration may be justified. But there is more involved.

First, if we are serious about subjecting warfare to legal assessment and accountability, we must apply the law with care. This may not sound like a profound insight, but the point is that without respecting the formal strictures of the law, including its technicalities, it is all too easy to take liberties and shortcuts that bend the rules out of shape. Invoking the language of the law then becomes yet another exercise in point-scoring, for whichever side, as we see on a daily basis. This is deeply corrosive.

Second, while a legal assessment of the pager attack is about the here and now, Article 7(2) APII CCW and other rules of the law of armed conflict have relevance beyond Gaza and Lebanon. How we apply the rules in the present context, how we resolve our disagreements and what interpretations and understandings of the law emerge as a result have consequences down the line. An interest in the rules as seen in the abstract, divorced from what is happening on the ground, should not be mistaken for scholarly aloofness or a lack of sensitivity towards the victims of the bloodshed in Gaza, Lebanon, Israel and elsewhere. 

Third, law is not ethics, but in this area, it raises ethical questions that cannot be ignored. We should not assume, however, that the answers to these questions point in the same direction. It is fashionable to portray humanitarian principles and military necessity as opposites and to indulge in the image of humanitarians valiantly defending the constraining function of the law of armed conflict against an onslaught of operational lawyers and worse who are hell-bent on enlarging its permissive dimension. These are caricatures. Like most caricatures, they bear some semblance to reality, but overstate the point. Yes, humanitarian concerns and operational requirements may pull in different directions. However, military might can also serve humanitarian imperatives. Defeating an evil such as ISIS requires the application of combat power. Inaction may not be morally cost free. The constraints imposed by the law must limit the adverse effects of war, otherwise they would betray their humanitarian intentions, yet they cannot jeopardize a belligerent’s chances of victory without also creating an overwhelming incentive to ignore the rules in the interest of survival. Accepting military necessity creates space for humanitarian considerations. The point to take away is that a single-minded focus on the humanitarian aspects of the law of armed conflict may do those principles a disservice. We need to accept some compromises and strive for some form of balance. 

So, yes, we should not overlook ethics, as Dr Roorda reminds us, when applying the law to war. Where compliance with the rules does not save a belligerent from acting inhumanely, ethics has a role to play. But, no, being mindful of the ethical dimension of the law of armed conflict cannot be reduced to an unyielding effort to maximize its constraining function, at least not without ignoring the moral complexity of war and risk weakening the very values this is meant to uphold. And, no, fidelity to technicalities against a backdrop of mass human suffering is not mistaking legal analysis for a game of ‘Is it Cake?’ or some other game-show; far from it. 

Article 7(2) APII CCW

The more formal disagreement with Dr Roorda revolves around the meaning of Article 7(2) APII CCW, particularly the phrase ‘specifically designed and constructed’. As these words form part of a treaty, our efforts to make sense of them need to be guided by the customary rules of treaty interpretation reflected in the Vienna Convention on the Law of Treaties (VCLT).

Ordinary Meaning

Let’s start with the ordinary meaning of the verbs ‘design’ and ‘construct’. Consulting a leading dictionary suggests that ‘design’ carries several meanings. The one most relevant in the present context is to ‘produce a design for something’, that is ‘[t]o make drawings for the construction or creation of (something, as a building, object, garment, etc.) according to certain aesthetic criteria’ or ‘to make plans for the production of (a device, product, etc.) according to structural or functional criteria (sometimes without the implication of aesthetic requirements)’. The relevant dictionary definition of ‘construct’ is ‘[t]o make or form by fitting the parts together; to frame, build, erect’.

Designing, that is making plans for the construction, creation or production of an object, implies a process whereby plans are made for working with different materials or parts to craft, build or assemble a new object. Construction too refers to a process whereby pre-existing materials or parts are fitted together to create something new. 

In this context, it is useful to consider the French language version of APII CCW, which is equally authentic pursuant to Article 11 of the Convention. The French text of Article 2(4) APII CCW defines booby-traps as devices or materials ‘conçu, construit ou adapté’, but Article 7(2) APII CCW refers to objects ‘conçus et fabriqués’. Consulting another dictionary suggest that the French verb fabriqué means ‘[d]oing something, making it from a raw material by manual, handicraft work’, in other words that it refers to constructing or assembling new objects. 

Context

Turning to context, it is notable that Article 2(4) APII CCW defines a booby-trap to mean ‘any device or material which is designed, constructed or adapted to kill or injure, and which functions unexpectedly when a person disturbs or approaches an apparently harmless object or performs an apparently safe act.’ Here, design and construct is distinguished from adapt, a verb which our earlier dictionary tells us means ‘[t]o alter or amend so as to make suitable for a new use or purpose; to modify’. 

The fact that Article 7(2) APII CCW applies to objects ‘specifically designed and constructed’ (emphasis added), but fails to mention ‘adapted’, seems intended to underline that the rule applies only to objects that are newly created or assembled to contain explosive material, to the exclusion of pre-existing objects that are adapted or modified to such an end. This conclusion is reinforced by the fact that Article 7(2) uses the conjunctive ‘and’, rather than ‘or’, meaning that an object has to be both designed and constructed, that is originally planned and subsequently manufactured, to contain explosive materials in order to fall within the scope of this provision.

Object and Purpose

Turning to the object and purpose of APII CCW, it is instructive to consult the preamble of the Convention. Humanitarian considerations feature prominently in the preamble, such as the protection of the civilian population or the prohibition of means and methods of warfare of a nature to cause superfluous injury or unnecessary suffering, together with broader goals, such as a desire to contribute to international détente, to end the arms race and to build confidence. As noted in the preamble, and reflected in the very title of the Convention, the treaty pursues these goals by prohibiting certain conventional weapons or by restricting their use. 

Accordingly, some parts of the Convention put in place complete prohibitions. Protocol I, for example, prohibits the use of any weapon the primary effect of which is to injure by fragments which in the human body escape detection by X-rays. By contrast, booby-traps and other devices are not prohibited per se, as underlined for instance in France’s Manuel de droit des operations militaires. Rather, APII CCW prohibits only certain types and certain uses, meaning that those types and uses that are not prohibited remain lawful, subject to compliance with any other applicable rules.

This means, first, that we must distinguish prohibited uses of booby-traps and other devices from permissible ones under APII CCW. Second, such a distinction is not incompatible with the object and purpose of the Convention. Third, we cannot simply assume that types and usages which have not been prohibited by APII CCW are regulatory gaps or oversights.

Dr Roorda suggests that a reading of Article 7(2) APII CCW which excludes adapted or modified devices is unpersuasive because it is at odds with the definition of booby-traps in Article 2(4) APII CCW, arguing that it seems unlikely that adapted or modified devices were intended to be covered by Article 2(4), only to then be excluded by Article 7(2).

This argument misunderstands the logic of APII CCW. The instrument defines booby-traps and other devices broadly in Article 2, but since neither booby-traps nor other devices are subject to a complete ban, subsequent provisions necessarily are more restrictive as they prohibit only certain, more limited types or usages. Protocol III on incendiary weapons follows a similar logic. 

It also overlooks the actual wording of Article 2(4) and Article 7(2) APII CCW. Article 2(4) defines a booby-trap as ‘any device or material’ that functions unexpectedly when a person disturbs or approaches another, apparently harmless object or performs an apparently safe act. To give an example, this includes a situation where a person opens a door which activates an explosive charge connected to the door by a hidden wire. By contrast, Article 7(2) applies to booby-traps or other devices ‘in the form of apparently harmless portable objects’. Here, the booby-trap is the harmless portable object, rather than a device or material that is activated by another, portable or non-portable, object. In any case, the prohibition in Article 7(2) applies only to devices containing explosives, whereas booby-traps as defined in Article 2(4) are not limited to explosive devices and materials, but may injure or kill through other mechanisms. Evidently, the prohibition in Article 7(2) is narrower than the general definition of booby-traps under Article 2(4). To declare this contrary to the humanitarian object and purpose of the Convention, which in any event is not the sole goal it pursues, rides roughshod over the express wording of APII CCW.

Preparatory Work

Still, Dr Roorda submits that a reading of Article 7(2) APII CCW that excludes adapted or modified devices would border on the ‘absurd’. Let us therefore turn to the travaux préparatoires, in accordance with the rule contained in Article 32 VCLT, whether it is to confirm the meaning we have arrived at above or to determine the meaning of Article 7(2) because it is, according to Dr Roorda, absurd. 

The original text of the Convention was negotiated in 1979 and 1980. The available preparatory work relating to the predecessor of Article 7(2) APII CCW does not appear to be extensive, but a Report of the Working Group on Landmines and Booby-Traps is on point. This states that what is now Article 7(2) was drafted to include ‘booby-traps that are otherwise sometimes known as “prefabricated” booby-traps and that could be mass-produced.’ This appears to confirm our interpretation: ‘prefabricated’ implies the construction or assembly of new objects, rather than the adaptation or modification of pre-existing ones. That this was the intent of the drafters is borne out by the subsequent recollections of members of the British and United States delegation to the conference. As the British delegate explained: 

What the Conference had in mind to prohibit were booby-traps made to look like watches, cameras, pens or other attractive items. It did not prohibit the booby-trapping of existing attractive items.

The available travaux préparatoires thus fully confirms the meaning we arrived at as a result of applying the general rule of treaty interpretation. 

Subsequent Practice

Moving beyond the travaux préparatoires, several national manuals also clarify that Article 7(2) APII CCW applies to prefabricated objects. The Law of Armed Conflict Commanders’ Guide published by Australia states the following, as cited by the International Committee of the Red Cross:

941. The use of the following types of booby traps is prohibited:

a. any booby traps in the form of an apparently harmless portable object which is specifically designed and constructed (prefabricated) to contain explosive material and to detonate when it is disturbed or approached or

The Military Manual of the Netherlands, as cited by the International Committee of the Red Cross, says: 

The use of booby-traps in the form of an apparently harmless portable object, specially designed to contain explosives and to explode when touched or approached, is forbidden. This means prefabricated booby-traps.

Referring to Article 7(2) APII CCW, the United Kingdom’s Manual of the Law of Armed Conflict declares that the 

prohibition relates to booby-traps made to look like watches, personnel audio players, cameras and the like. This is to prevent the production of large quantities of dangerous objects that can be scattered around and picked up by civilians, especially children. It does not prohibit, subject to paragraph 6.7.5, the booby-trapping of existing items of that sort.

Echoing the United Kingdom Manual, the United States Department of Defense Law of War Manual declares as follows (footnotes omitted): 

This prohibition relates to booby-traps manufactured to resemble items, such as watches, personal audio players, cameras, toys, and the like. This prohibition is intended to prevent the production of large quantities of dangerous objects that can be scattered around and are likely to be attractive to civilians, especially children. This rule does not prohibit the use of booby-traps in connection with non-portable objects, such as a door or gate.

This rule does not prohibit field-expedient adaptation, or adaptation in advance, of objects for use as booby-traps or other devices that are not designed or constructed for such use. For example, it would not be prohibited to improvise a booby-trap using a trip-wired hand grenade in the form of an apparently harmless portable object. Such improvisation of booby-traps, for example, to retard an enemy advance, does not pose the same sort of danger to from the civilian population as the mass production of objects specifically designed as booby-traps.

This explanation given by the Law of War Manual should further ease concerns that a tension exists between Article 7(2) APII CCW and the humanitarian objectives of the Convention. Excluding adapted or modified devices from the scope of the rule does not hollow out its protective scope, as the prohibition still applies to a wide range of other objects. Also, devices that are not covered by Article 7(2) are subject to the limits set out in Article 7(1) APII CCW.

Conclusion

Considering the ordinary meaning and context of Article 7(2) APII CCW in the light of the object and purpose of the Convention, and comparing this against the preparatory work and subsequent practice, consistently leads to the same conclusion: the rule excludes adapted or modified devices. The text is not indeterminate or internally conflicting and the original intent of the drafters is not unclear or ambiguous, contrary to what Dr Roorda suggests.

In relation to the pager attack, this means that Article 7(2) APII CCW applies to the pagers only if they were prefabricated, that is specifically designed and constructed from component parts, rather than adapted or modified. I think it is reasonable to argue that prefabrication includes not only situations where a device is built from scratch, using basic component parts such as nuts and bolts, but also where the design and build incorporates more complex components, such as pre-existing circuit boards, batteries or assemblies. Where the pagers lie on this spectrum depends on how they were designed and constructed, which is not entirely clear, as reporting on the subject is not consistent (e.g. see here and here).

Finally, it should be underlined that even if Article 7(2) APII CCW is not applicable in the present case, either for the reasons set out in this post or because of different factors, the attack still had to comply with other rules of the law of armed conflict, including, in particular, the duty of distinction.