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Max Planck Encyclopedia of Public International Law [MPEPIL]

Arms Control

Adrian Loets

From: Oxford Public International Law (http://opil.ouplaw.com). (c) Oxford University Press, 2015. All Rights Reserved.date: 20 February 2019

Arms control — Weapons control — Weapons, chemical — Weapons, nuclear — Armed conflict

Published under the auspices of the Max Planck Foundation for International Peace and the Rule of Law under the direction of Rüdiger Wolfrum.

A. Concept and Definition

There is no uniform definition of arms control. According to a recent definition by Den Dekker, the concept can be broadly described as ‘unilateral measures, bilateral and multilateral agreements as well as informal regimes (‘politically binding’ documents, ‘soft’ law) between States to limit or reduce certain categories of weapons or military operations in order to achieve stable military balances and thus diminish tensions and the possibility of large-scale armed conflict’. Arms control law consequently refers to ‘that part of public international law that deals with the restrictions internationally placed upon the freedom of behaviour of States in regard to their national armaments, and with the applicable supervisory mechanisms’ (den Dekker 316–317; similarly Morgan 17).

The distinction between disarmament and arms control is unclear. Both terms relate to armament and can comprise quantitative and qualitative restrictions on weapons in general or on certain types of weapons. The difference lies in the aim: whereas disarmament seeks to reduce military capacity of all States—eventually to zero—arms control is primarily concerned with curbing the build-up of arms by introducing quantitative or qualitative ceilings for weapon systems, arms, and man power (Ipsen 1133–1134). Arms control attempts to stabilize the security environment but does not necessarily entail reduction of military capability. It can also include preventive prohibitions of the development, testing, or build-up of certain armaments or of technologies threatening to upset the strategic balance, such as anti-ballistic missiles (‘ABMs’). Non-proliferation (Weapons of Mass Destruction) represents another important pillar. In addition, the temporal scope of an instrument can provide an indication for its classification: arms control agreements are sometimes concluded for a limited time frame (although they would be extendable) whereas disarmament commitments, in accordance with their aim for perpetual peace, are usually of indefinite duration (Venturini 347).

Frequently, arms control is complemented by other stabilizing instruments, for example, voluntary confidence-building measures. It can be distinguished between mutually agreed arms control conventions and unilaterally applicable limitations.

B. Evolution of Arms Control

1. Origins before 1945

Efforts to limit armament and certain weapon types date back to old times. There is evidence of an armament conference in ancient China of 546 BC. In 1139, the use of the crossbow (against Christians) was banned by the Second Lateran Council (Dupuy and Hammerman 3–11). One of the first modern examples is the Rush–Bagot Agreement of 1817 between the US and Britain, restricting the number of naval forces on the Great Lakes. With the advent of humanitarian law in the late 19th century, restrictions on particular weapons, as well as methods and means of warfare emerged (Warfare, Methods and Means; Weapons, Prohibited). Notably the 1868 St Petersburg Declaration and the Conventions resulting from the Hague Peace Conferences (1899 and 1907) are to be cited in this context. The Versailles Peace Treaty (1919) subjected the German armed forces to quantitative restrictions and established a verification regime. Further limitations of naval armament (Naval Warfare) were adopted in a series of conferences in London and Washington in 1922 and throughout the 1930s.

This brief overview demonstrates the ambiguous motivation behind armament restrictions. The Treaty of Versailles clearly pursued the objective of containing Germany’s military power but also States that this was done ‘in order to render possible the initiation of a general limitation of the armaments of all nations’. The humanitarian initiative by the Russian Tsar Nicholas II leading to the St. Petersburg Declaration, as well as the Rush–Bagot treaty were at least partially induced by soaring armament costs (Keefer 7–9).

2. Development of Nuclear Arms Control after 1945

In the period after World War II, the arms control debate centred on the new and destructive nuclear weapons (Nuclear Weapons and Warfare). The Soviet Union’s first nuclear test in 1949 triggered a nuclear arms race that was defining for the Cold War (1947–91). Efforts to place nuclear weapons under international control within the UN framework failed due to increasing mistrust between the superpowers (Superpowers and Great Powers). Yet, in 1963, a Partial Test Ban Treaty was adopted by the USSR, the US, and the UK, prohibiting testing in the atmosphere, under water, or in space. The original ambition of reaching a Comprehensive Nuclear Test Ban Treaty (‘CTBT’) was thwarted by disagreement on the supervision. Nevertheless, another partial restriction was introduced by the Threshold Test Ban Treaty of 1974, limiting underground testing of nuclear warheads above a certain size. A CTBT was finally agreed upon in 1996, but is still awaiting sufficient ratification.

On another track, the US and the USSR began to discuss reducing the number of nuclear weapons in the Strategic Arms Limitation Talks (SALT). The first SALT agreement (‘SALT I’) 1972 stipulated a moratorium on land- and submarine-based intercontinental ballistic missiles. A reduction of ABM launching facilities was agreed upon in the ABM Treaty of 1972 and the ABM Protocol of 1974, from which the US withdrew in 2001. Negotiations for further reductions (‘SALT II’) were only concluded in 1979. Due to the Soviet invasion of Afghanistan that year, the US halted the ratification process. Still, both sides tacitly complied with the agreement in the years that followed on the basis of reciprocity. Continued talks finally led to the Treaty between the United States of America and the Union of Soviet Socialist Republics on the Elimination of their Intermediate-Range and Shorter-Range Missiles (‘INF Treaty’) in 1987, in which the elimination of short- and medium-range missiles was pledged

The SALT negotiations aimed at limiting the number of weapons owned by the nuclear powers, in other words, at vertical proliferation. Faced with the prospect of a growing number of countries pursuing nuclear weapons programmes in the early 1960s, another dimension of arms control, notably horizontal non-proliferation, was tackled. The outcome, the Non-Proliferation Treaty (1968), rests on three pillars. First, it obliges States that had not exploded a nuclear weapon before 1967 (Non-Nuclear Weapons States, ‘NNWS’) to refrain from obtaining such weapons. This obligation is supervised by the International Atomic Energy Agency (IAEA) (non-proliferation pillar). Second, the right of States to peaceful use (Nuclear Energy, Peaceful Uses) is reiterated (peaceful use pillar). Third, in exchange for the abstinence of NNWS, the nuclear weapons States (‘NWS’) pledge to pursue nuclear disarmament in good faith (bona fide) (disarmament pillar). Although the treaty enjoys wide ratification and is mostly considered a success, its compliance and verification record are equivocal, and it has not stopped signatory States from (successfully) engaging in military nuclear programmes. In addition—while representing a relative success compared to the failed 2005 NPT Review Conference—the 2010 conference again could neither agree on specific disarmament time frames nor a global verification standard, joint responses on default by signatory States, nor multilateral fuel supply schemes. An important outcome of the 2010 conference was the call for a Nuclear Weapons Free Zone (‘NWFZ’) in the Middle East under UN auspices, even though the conference on the issue planned for December 2012 has been indefinitely postponed

3. From START and SORT to a New START

On the bilateral track, it was not until 1991, immediately before the dissolution of the USSR, that the round of talks labelled ‘Strategic Arms Reduction Talks’ (‘START’), was concluded with a treaty between the US and the USSR (‘START I’) introducing fixed caps for warheads and missiles. A second treaty (‘START II’) was adopted in January 1993, but never ratified by Russia. However, further reductions were agreed upon in the 2002 Strategic Offensive Reduction (‘SORT’) treaty. On 2 April 2010, Presidents Obama and Medvedev signed the latest nuclear reduction agreement (‘New START’) in Prague, so as to replace the expired START I along with SORT, which was bound to run out in 2012 (for details on the commitments see Woolf 3–14). New START does not, however, address the particularly contentious issue of American ABM systems, and is limited to strategic weapons (Kerry 112–115). As the latest step, the US adopted a revised Nuclear Posture Review Report in late 2010, unilaterally declaring that nuclear weapons would not be used against non-nuclear weapons States (paras vii–viii) (Moxley 755–773). Unofficial remarks by the US and Russian Presidents at the side of the Seoul Nuclear Security Summit in March 2012 indicated their willingness for further reductions in the future.

C. Arms Control under the UN Charter

10 Within the United Nations framework, both the General Assembly (‘UNGA’) and the Security Council (‘UNSC’) play a role in arms control. The UNGA’s role lies mainly in the preparation of multilateral conventions. Pursuant to Art. 11 United Nations Charter, it can make recommendations on the ‘principles governing disarmament and the regulation of armaments’ to the Member States and the UNSC. The Assembly’s First Committee mainly administers this function. With the gridlock in the UN Conference on Disarmament, it has become an important arms control forum in the UN system and has passed several significant arms control resolutions at its 2012 session. The UNSC is ‘responsible for formulating … plans to be submitted to the Members of the [UN] for the establishment of a system for the regulation of armaments’, assisted by the Military Staff Committee (Arts 26, 47). In practice, however, the Council has been relying on its far more effective Chapter VII powers to impose unilateral obligations on certain States. UNSC Resolutions 687 and 1441, for instance, prescribed highly detailed arms control obligations for Iraq (Iraq–Kuwait War [1990–91]).

D. Control of Biological and Chemical Weapons

11 Unlike in the case of nuclear weapons, biological and chemical weapons have been outlawed for some time. The Geneva Protocol 1925 on gas warfare represents an early example. The Biological Weapons Convention (‘BWC’) was already adopted in 1972, and entered into force in 1975 (Biological Weapons and Warfare). The Chemical Weapons Convention (‘CWC’) became effective in 1997 (Chemical Weapons and Warfare). Both the BWC and the CWC establish absolute prohibitions of biological or chemical weapons agents, and require the destruction of previously produced stocks (Arts II BWC and I (2) CWC), although the USSR pursued a clandestine biological weapons programme after its ratification. Significant differences exist between the two agreements’ verification and compliance regimes. There is also an absolute prohibition of the use of biological and chemical weapons, including gas weapons, under customary international law.

E. International Humanitarian Law and Arms Control

12 It is now recognized that international humanitarian law, although not directly concerned with arms control, imposes prohibitions as well as limitations on the use and development of certain weapons. Notably the principle of distinction and the prohibition of inflicting superfluous injury or unnecessary suffering, which are considered customary law by the International Committee of the Red Cross (ICRC) (ICRC Customary Humanitarian Law Study, Rules 1–6, 11–12, 71), are of ‘considerable contextual importance’ to the law of arms control (Boothby 41).

13  Art. 51 (4) (b) and (c) AP1 (Geneva Conventions Additional Protocol I [1977]) provide that ‘a method or means of combat which cannot be directed at a specific military objective’ or ‘the effects of which cannot be limited as required by [the] Protocol’ are prohibited. The International Court of Justice has affirmed in its Nuclear Weapons Advisory Opinion of 1996 that ‘weapons which are incapable of distinguishing between civilian and military targets’, in other words intrinsically indiscriminate weapons, are prohibited under customary international law (at para 257; Nuclear Weapons Advisory Opinions) (Indiscriminate Attack). The difficulty is to determine whether a particular weapon is incapable of distinction by design and not merely used in an indiscriminate way (Dinstein 62).

14  Art. 35 (2) AP1 expressly prohibits ‘weapons, projectiles and material and methods of warfare of a nature to cause superfluous injury or unnecessary suffering’. This is commonly understood to prohibit the use of weapons that (objectively) do greater harm than that inevitable to achieve legitimate military objectives (Dinstein 65). Again, the difficulty is to identify the specific arms in contradiction of the principle (see Pilloud and others paras 1419–1425).

15 There are established customary law prohibitions of certain weapon types with regards to these two principals, for instance poison, biological and chemical agents, gas warfare and expanding or exploding bullets (ICRC Customary Humanitarian Law Study, Rules 73–80). For other weapons, for instance land mines and incendiary weapons, customary law stipulates at least limitations of their use. Frequently, the two principles will overlap but some weapons, such as blinding laser beams, are expressly prohibited under the consideration of causing superfluous injury (Dinstein 79).

16 Beyond these general rules, the Convention on Certain Conventional Weapons of 1980 and its five Protocols specifically prohibit a number of conventional weapons considered to have indiscriminate effect. Although the Protocols prohibit some particularly contentious weapons such as booby traps (Protocol II) and non-detectable fragments (Protocol I), they do not stipulate an outright ban on land mines (Protocol II) and unexploded remnants of war (Protocol V). In addition, Protocol V only covers defective unexploded ordnances, and consequently not unexploded but functional cluster munitions (Docherty 944).

17 The 1997 Ottawa Convention stipulates a comprehensive ban of anti-personnel mines. The similarly phrased Convention on Cluster Munitions entered into force in August 2010 and has so far attracted 82 State parties. Due to its strong preventive and remedial obligations, it has been considered as one of the most extensive arms control treaties (Docherty 949–962). The most important owners and manufacturers of these weapons have, however, not ratified the conventions at the time of writing.

F. Regional Arms Control Arrangements

18 Given the overarching aim of enhancing stability, some arms control treaties specifically regulate strategic balance on a regional level. In the 1974 Ayacucho Declaration, eight Latin American States generally pledged ‘effective limitation of armaments’. On the European level, the Conventional Armed Forces in Europe (‘CFE’) Treaty (Conventional Armed Forces in Europe [CFE] Regime) entered into force in 1992 under the auspices of the Organization for Security and Co-operation in Europe (OSCE). Its initial purpose to ensure parity between the forces of the Warsaw Treaty Organization and the North Atlantic Treaty Organization (NATO) by capping the deployment of certain weapon systems, a notification, and an on-site inspection system, was outrun by the dissolution of the Eastern bloc in 1991. The treaty was accordingly revised at the 1999 review conference and the verification mechanism strengthened. Since 2007, however, Russia has suspended its participation in the CFE regime due to the ABM dispute with the US. Regional treaties on NWFZ, on the other hand, belong to the realm of disarmament law.

G. Problems and Criticism

1. Constant Need for Adjustment

19 One issue is that even the most detailed and sophisticated arms control regimes remain vulnerable to changing external circumstances. Firstly, technological progress can have a destabilizing effect on the carefully balanced equilibrium. The present ABM dispute between the US and Russia demonstrates this problem quite aptly. Another example is the development of small tactical nuclear weapons (so-called ‘mini nukes’) or unmanned war drones. Secondly, internal political considerations could also cause governments to ignore their treaty obligations and increase armament (Schmalzgruber 214–248), for example in the case of North Korea.

2. Implementation and Supervision

20 The intensity of supervision between the different arms control treaties varies significantly. As a rule, however, where international (and not merely unilateral) supervision is provided for, there is usually a focus on mere monitoring. Some treaties also provide for verification, that is the assessment of compliance regarding a particular finding, normally by an international organization, and requires a complaint by a State party to trigger the mechanism. Where conventions charge international organizations with the supervision, these tend not to be competent to take sanctions for the enforcement (International Organizations or Institutions, Supervision and Sanctions). Rather, they represent mere forums for debate between the State parties.

21 Generally, the instruments range from mere reporting duties and routine inspections (monitoring) to more invasive ad hoc inspections, sometimes so-called ‘challenge inspections’ at the request of a Member State (verification), up to compulsive methods in case of a determined breach (enforcement).

22 One example of supervision of an arms control treaty by an international organization is the IAEA’s supervision of the NPT. Here, supervision encompasses all three elements, monitoring, verification, and enforcement. Supervision is organized through bilateral Comprehensive Safeguards Agreements, providing for reporting duties, routine inspections, as well as unannounced inspections, and remote supervision of facilities. Most States have also ratified an Additional Protocol with the organization (Model Additional Protocol), providing for further monitoring measures (Venturini 363). In case of determined non-compliance, the IAEA can request remedial action, and, failing that, the Board of Governors can relate the matter to the UNSC or the UNGA.

23 The CWC is supervised by the independent Organization for the Prohibition of Chemical Weapons (‘OPCW’), inter alia through reporting duties and inspections. It also provides for a challenge inspection procedure which is considered one of the most extensive verification procedures in the law of arms control, but has never been used, mainly due to political constraints (Asada 88–92).

24 By contrast, the BWC’s supervisory mechanism mainly consists of review conferences in five year intervals. The State parties have the option of initiating a complaint procedure about a suspected breach to the UNSC which has, however, never been triggered. Negotiations to install an independent supervisory organization have been stalled since 2001.

25 Weak verification and enforcement mechanisms represent a main challenge for the effectiveness of arms control law. A stabilizing effect, it has been argued, required that the State parties could rely on the compliance of the other side, excluding any possibility of deception. Other scholars have acknowledged the benefits of the more ‘managerial’ supervision in arms control law with a focus on confidence building and informal exchange of information. They have pointed out that breaches of arms control law are difficult to prove for third States and that a confrontational and enforcement-oriented supervision might lead to increased tensions instead of stability (den Dekker 323–329).

26 The track record of arms control supervision supports both views. Despite the relatively strong supervision, CWC has produced mixed results regarding the obligation to destroy weapon stocks (Venturini 375). But also the more informal BWC scheme has had only modest success. It did not prevent the USSR from pursuing a secret biological weapons programme despite its being party to the Convention. In the case of Iraq, the referral to the UNSC could not resolve the issue and the conflict ended in a US armed intervention. The procedure also did not dissuade North Korea from testing three nuclear devices and several missile systems. To date, it remains unclear whether the sanctions against Iran will be able to stabilize the conflict about its nuclear programme.

H. Conclusions and Outlook

27 With the end of the Cold War, arms control has entered into a new phase. Yet, although the rivalry between the blocs has diminished, the idea of agreeing on mutually binding armament limitations and subjecting them to international supervision remains topical for the maintenance of a stable security environment. The ongoing tensions between the US and Russia over the ABM Treaty adequately demonstrate the need for such agreements as well as their fragility in the face of conflicting geostrategic interests. Even if the superpowers can agree on further reductions of nuclear weapons, neither of them is yet willing to relinquish them entirely, as the staggering maintenance and overhaul investments by NWS demonstrate. Their failure to determinedly pursue disarmament also upsets the bargain at the heart of the NPT regime, certainly contributing to its inability to halt proliferation. Nuclear arms control is likely to become more complicated with the rise of new powers and the ensuing struggle for a new strategic balance. Implementation and supervision of the existing arms control treaties are also still in want of improvement. A major challenge is the frequent occurrence of non-international armed conflict and the risk of weapons of mass destruction, not only nuclear devices, falling in the hands of non-State actors. Ideas to overcome the political deadlock in present arms control negotiations are on the table: in order to prepare the ground for the (currently stalled) negotiations on a Fissile Material Cut-Off Treaty, a uni- or bilateral moratorium on the production of fissile materials could be declared. The ABM dispute could be assuaged by a cooperative NATO–Russian missile defence arrangement for a trial period (Pifer and O’Hanlon 11–14). The CTBT ratification could be revitalized by unilateral moratoria or the dismantling of testing facilities (like France did, Danon 150–151). Establishing a reliable and impartial multilateral fuel supply could strike a compromise between the need for verification and the right to peaceful use. Although general and complete disarmament may be politically unattainable in the foreseeable future, the approach of realistic and small steps that characterizes arms control stays as relevant as ever in paving the way to an eventual ‘global zero’.

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