The Trench

Biological Chemical Nuclear

A Middle East Zone Free from Non-conventional Weapons (4)

Share this article

Part 4: Clear legal definitions at the core of the future treaty


This article is the fourth in a series of blog postings exploring the opportunities and challenges facing a new series of conferences at the United Nations in New York to eliminate non-conventional arms – essentially nuclear weapons, and to a lesser extent chemical and biological weapons (CBW) – from the military arsenals in the Middle East.

Why legal definitions matter

By adopting Decision 73/546 on 22 December 2018, the UN General Assembly tasked the newly established conference with ‘elaborating a legally binding treaty establishing a Middle East zone free of nuclear weapons and other weapons of mass destruction, on the basis of arrangements freely arrived at by the States of the region’ (emphasis added).

Any international agreement concluded between states in written form and governed by international law must necessarily include definitions. Multiple terms eventually ending up in the treaty binding the Middle Eastern States will have their legal explanation in the 1969 Vienna Convention on the Law of Treaties.

Other definitions, however, will be unique to the Middle East zone free of non-conventional weapons. The previous blog posting in this series addressed how the negotiators presently circumscribe the ‘Middle East region’. They rely on a country list used by the International Atomic Energy Agency (IAEA) – essentially the members of the League of Arab States plus Iran and Israel – to invite participants to the talks. Whether these countries will actually make up the zone is but one question awaiting an answer.

Certain types of definitions will affect the implementation of the future agreement. According to Decision 73/546 the conference ‘shall take as its terms of reference the resolution on the Middle East adopted by the 1995 Review and Extension Conference’ (pp. 13-14). The conference participants must therefore strive for a zone that is ‘effectively verifiable’. This ambition entails defining the objects of verification, the types of information required from parties to the agreement, and the mechanisms that will enable collecting and processing of such information, as well as responding to detected anomalies or alleged violations.

Officials from Middle Eastern states refuse at this early stage to engage on the nature of that verification regime. Many functional definitions will emerge and garner consensus as the negotiations advance. In contrast, terms that aim to define purpose and object of a future treaty require early consideration because they set central negotiation parameters. They will eventually determine the future agreement’s scope. Initially, some of these definitions too will necessarily be broad. Step by step diplomats will refine them once they turn their focus to the future treaty’s functioning.

The weapon spectrum

The 1995 Resolution also expanded the idea of a Nuclear Weapon Free Zone to a ‘zone free of nuclear weapons as well as other weapons of mass destruction’. In this debate diplomats and experts generally take the ‘other weapons of mass destruction’ (WMD) to comprise chemical, biological and radiological arms. The expression, however, lacks an international legal definition. Its outline is fluid. Especially in its popular conception WMD may also cover explosives, missiles, cyber weapons, or use of any type of weapon that leads to large-scale (indiscriminate) human casualties, damage to infrastructure or environmental devastation. Consequently, just like people have ended up with listing the countries that make up the Middle East, they incline to itemise the weapon classes. Absent a specific understanding of each category, this simply shifts the definitional problem.

For legal delineation of individual arms categories diplomats and experts may point to existing weapon control treaties. This raises separate challenges because the agreements approach the governance of a given weapon category from fundamentally different angles. A disarmament treaty (going to zero) differs from an arms control agreement (managing levels of weaponry) and both have goals that are quite distinct from or exceed those in non-proliferation arrangements. In reality the substantive components making up a weapon definition vary in accordance with a treaty’s verification ambitions. Importing those disparate definitions into a single legal instrument – formally or by way of understanding – would inevitably affect the wholeness of the zone’s verification regime.

In addition, while the principal classes of non-conventional weaponry may seem discrete entities, they actually share fuzzy boundaries with several intermediate categories in between. These pose less of an issue in treaties covering a single arms category. Two or more instruments may partially overlap to foreclose legal loopholes. In contrast, an intermediary category may also escape legal regulation. The figure below illustrates how relationships connect the three principal categories of biological, chemical and nuclear arms.

Non-conventional weapons - The spectrum
Non-conventional weapons – The spectrum

The linkage between biological and chemical weapons is straightforward and widely recognised. Biological weapons (BW) refer to self-replicating microbial organisms that cause infection. Chemical agents comprise toxic substances that through chemical action interfere with life processes, thereby harming or killing living organisms (humans, animals, plants). Toxins are poisons produced by living organisms – animals, plants or microbes. Unsurprisingly, both the Biological and Toxin Weapons Convention and the Chemical Weapons Convention cover toxins, thereby precluding a legal loophole.

Nuclear weapons (NW) rely primarily on blast and thermal radiation producing heat for their destructive effects. The release of ionising radiation is a third major consequence that has long-lasting, even trans-generational health consequences for survivors and impacts the environment.

Radiological weapons (RW) exploit radiation for military purposes. This places them between chemical and nuclear weapons. Radiation is a form of poisoning, but in contrast to a CW’s chemical action on the life processes, a radioactive source emits the poisoning rays. On the one hand, enhanced radiation weapons or so-called neutron bombs sought to limit the destruction of property and infrastructure from blast and heat to make them more useful in limited nuclear wars. On the other hand, highly radioactive materials can be disseminated by means of a conventional detonation or some mechanical dispersal device and thus contaminate the environment like CW. No specific treaty limits the development, production, possession or use of RW.

Incendiary weapons represent another link between chemical and nuclear weapons. As noted earlier, heat and fire are one the three main effects of a nuclear detonation. Like CW incendiary weapons rely on chemical reactions, but harm to living organisms and damage to property result from heat generation. Certain types of incendiary weapons may also generate toxic fumes, but unless someone deploys these munitions to exploit such poisonous properties, they would not be classified as CW.

Finally, smoke links CW with incendiary weapons. Some incendiary weapons generate smoke, which the military may use for target marking or masking operations. Smoke results from a chemical reaction and may in some instances produce poisonous fumes. As with incendiary weapons, smoke would not count as a CW unless intentionally generated as a toxic cloud.

Each arms class can conceivably be sharply defined, but in all likelihood the distinctions will conflict with historical or common understandings of the weaponry and their use. Meanings may also vary according to country or past national organisation of special military units responsible for their employment in combat. Widespread assumptions that white phosphorus or depleted uranium munitions are CW are but two examples.

What kind of legal definition for weapons?

The most straightforward way of defining chemical, biological, radiological and nuclear weapons seems drawing on existing international agreements. However, the governance models for the four arms categories differ considerably and definition quality consequently ranges from the complex (CW) to the virtually non-existent (RW). Furthermore, some definitions (CBW) enjoy universal acceptance, whereas other ones (RW and NW) have limited regional application at best. By universal acceptance I mean being part of a global treaty in force.

The character of a weapon definition – in terms of its complexity and the nature of defined objects – correlates with an agreement’s verification machinery. For instance, international instruments without verification requirements do not define the arms they govern. Furthermore, a qualitative difference emerges depending on whether a treaty addresses technologies with dual-use potential and therefore requires intrusion into civilian, non-military technology production and consumption processes, or limits itself exclusively to military equipment and materials.

In the former case, the all-encompassing definition will take ‘purpose’ for which a technology with dual-use potential might be applied as its central pillar (CBW). The definition of any other concept will depart from that central notion of ‘purpose’.

In the latter case, the tendency will be towards long lists with terms that each require a shared understanding among treaty parties. A good example is the Annex – Terms And Their Definitions to the 1991 Treaty Between the United States of America and the Union of Soviet Socialist Republics on the Reduction and Limitation of Strategic Offensive Arms, and its Annexes, Protocols, and Memorandum of Understanding (START II Treaty), which totals no less than 124 defined words and concepts.

A third broad option consists of referral to another international legal instrument or institution for either verification or definitions. Both the 1968 Non-Proliferation Treaty (NPT) and the 2017 Treaty on the Prohibition of Nuclear Weapons (TPNW, has not yet entered into force) rely on IAEA comprehensive safeguards arrangements for their verification requirements. The TPNW (Article 4, para. 6) also foresees ‘the competent international authority or authorities to negotiate and verify the irreversible elimination of nuclear-weapon programmes, including the elimination or irreversible conversion of all nuclear-weapon-related facilities’. Negotiators deferred the verification of destruction requirement to some unspecified future point when a nuclear weapon state (as defined under the NPT) or a nuclear armed state (not recognised under the NPT) may join the TPNW. The text also seems to leave open the possibility of different arrangements for each NW possessor rather than foreseeing a single mechanism applicable to all.

UN Security Council (UNSC) Resolution 1540 (2004) takes a hybrid approach. It does not define the arms classes it governs. Yet, it presents its own definitions for ‘means of delivery’ and ‘non-state actor’ (albeit in footnote only) and refers to outside legal sources for ‘related materials’, which comprise multilateral treaties, plurilateral (e.g. export control) arrangements, as well national control lists. It is clear that the scope of the latter concept may vary from UN member to UN member.

In summary, the negotiators of the treaty eliminating all non-conventional weapons from the Middle East face a most profound choice between designing definitions for the various weapons classes and associated technologies, on the one hand, and relying on previously agreed definitions, thereby importing the scope, depth and purposes of external treaties. From this summary overview it also follows that if zone is to be verifiable, then not having any weapon definitions is not an option.

How to approach defining an arms category?

Treaty definitions of weaponry tend to fall into one of two types:

  • all-embracing definitions that focus on purpose for which a technology may be applied; and
  • technical descriptions of particular technological items that circumscribe particular features, functions or capacities (e.g. size, payload capacity, throw weight, radius of action, etc.).

An all-embracing definition may be supplemented with more technical ones for underlying or ancillary technologies.

Furthermore, treaty definitions can also mark three subcomponents of the weapon system:

  • Payload (the agent or explosive device) as well as their ways of obtainment or production;
  • Delivery systems; and
  • Other special equipment related to weapon use.

For each one of those groups, the definition must establish boundaries (what is included; what is excluded), identify any precursor or underlying technologies, cover different possible production methods, and so on. Furthermore, it must characterise any additional treaty term to remove any ambiguity from the core definition.

The next two instalments of this series discuss how international law defines CW and BW (Part 5) and NW and RW (Part 6) taking the above considerations into account. Besides the core treaties, the analysis also looks at other instruments such as UNSC resolutions, export control arrangements and multinational transfer regulations as possible sources of inspiration for weapon definitions.



Part 1: A new process for the Middle East
Part 2: Treaties governing chemical and biological weapons
Part 3: Defining the Middle East, a loaded question
Part 4: Clear legal definitions at the core of the future treaty
Part 5: Regional security and the Chemical Weapons Convention: Insights for the Middle East (Part 1)
Part 6: Regional security and the Chemical Weapons Convention: Insights for the Middle East (Part 2)

Write a Comment

Your email address will not be published. Required fields are marked *

Subscribe to The Trench blog by filling in the form below.