In the previous two sections, we have learned what the objectives of arms control are, as well as what concepts and what kind of weapons exist. We will now take a look at the different forms that arms control can take once states parties have agreed on the course of action and the weapon system they would like to control.
Depending on the objective and the weapon system, various forms arms control are possible.
Quantitative and qualitative arms control
Quantitative limits
Firstly, if the objective is arms control, one common form is to place a quantitative limit on the overall number of weapon systems or their subcomponents. One example of this is the New START Treaty between the United States and the Russian Federation. The treaty will expire in February 2026, but until then, it will limit the two states’ nuclear arsenals as follows:
- Deployed delivery vehicles: 700
- Deployed warheads: 1,550
- Deployed and non-deployed launchers: 800
As you can see, New START limits delivery vehicles, warheads and launchers. Another example is the now defunct Conventional Forces in Europe (CFE) Treaty, which entered into force in 1992 and limited the conventional forces of NATO and the Warsaw Pact. Each side was limited to:
Limitations of NATO and the Warsaw Pact
Source: Grübelfabrik (CC BY NC)
Obviously, if the goal is the total elimination of a specific weapon system, this is essentially also a quantitative approach, with the limit set at zero.
Qualitative restrictions
The second option for arms control is qualitative restrictions, which focus on certain properties of weapon systems. For example, the Intermediate-Range Nuclear Forces (INF) Treaty banned US and Soviet nuclear and conventional ground-launched ballistic missiles and cruise missiles with a range between 500 and 5,500 kilometres.
The Intermediate-Range Nuclear Forces (INF) Treaty limits the range of conventional ground-launched ballistic missiles and cruise missiles
Source: Grübelfabrik (CC BY NC)
The property that was controlled in this case was missile range. Qualitative restrictions also play an important role when it comes to the regulation of emerging disruptive technologies. Autonomous functions in weapon systems, for example, are intangible and cannot be counted.
If the goal is non-proliferation, then the tool of choice is usually export controls. Export controls seek to prevent the spread of certain weapons or technologies around the globe by controlling the export of specific goods. Some examples of export control regimes are:
- Australia Group (chemical and biological weapons)
- Missile Technology Control Regime (missiles and missile technology)
- Nuclear Suppliers Group (nuclear materials and technology)
- Wassenaar Arrangement (conventional weapons and dual-use items)
- Zangger Committee (nuclear materials and technology)
You can learn more about these regimes in Learning Unit 12.
Actors involved
When we think of arms control, we usually think of two adversaries agreeing on common ceilings for weapon systems. This is the typical understanding of arms control from the Cold War. But it is not the only form. Arms control measures vary along three lines: 1. the actors involved, 2. the normative status of the agreements and 3. the point in the arms cycle at which the measures are taken. Arms control measures can be taken by one, two or more actors, i.e. they can be unilateral, bilateral or multilateral.
Unilateral arms control
Unilateral arms control measures are those a state takes independently, without consulting the opponent, to restrict its own armaments. The aim of such measures may be to signal peaceful intentions and the possibility of joint agreements to the opponent. They are a goodwill gesture and communicate, at least implicitly, the expectation that the opponent will reciprocate or is willing to cooperate.
However, it is often unclear whether unilateral arms control initiatives are motivated by genuine arms control concerns or by technological and financial difficulties. One aim of unilateral measures may be for a state to deter an opponent from engaging in arms efforts until their own capabilities have grown to such an extent that lifting the restrictions would give them significant advantages. However, ethical, political or economic reasons can also lead to unilateral arms control measures.
Examples of unilateral arms control
In the late 1980s, South Africa ended its nuclear weapons programme and became the first country to unilaterally eliminate all of its nuclear capabilities. After the end of the Cold War, the United States removed thousands of tactical nuclear weapons from Europe without demanding the same of the Soviet Union. And in the same year, Russia and the United States declared unilateral moratoria on nuclear testing, which were later incorporated into the provisions of the Comprehensive Nuclear Test-Ban Treaty (CTBT) in 1996.
Critics have objected to unilateral measures, claiming that they are dangerous because opponents could exploit them. However, many bilateral and multilateral arms control negotiations have only become possible because unilateral action paved the way.
Bilateral arms control
Bilateral arms control prevailed during the Cold War and also dominates arms control theory to this day. It is based on negotiations between two actors to regulate or completely prohibit the development, production, deployment or use of certain weapon systems. The aim is to establish a stable and predictable relationship between two adversaries. Two properties characterise bilateral arms control: reciprocity, i.e. the symmetry of the agreements entered into, and verification, i.e. the existence of mechanisms for monitoring compliance through inspections or similar procedures (for more on verification, see Section 4 below).
Examples of bilateral arms control
After the US lost its nuclear supremacy in the 1950s and the Cuban Missile Crisis almost resulted in a nuclear catastrophe, the US and the Soviet Union agreed to bilateral negotiations to reduce the risks of nuclear armament. In 1972, two important arms control treaties were concluded: the ABM Treaty to reduce anti-ballistic missiles and the SALT I Interim Agreement to limit strategic, i.e. intercontinental nuclear weapons. In the period that followed, bilateral arms control treaties were also concluded for other weapon systems (e.g. the 1987 Intermediate-Range Nuclear Forces Treaty, or INF Treaty) – you can find more information on these treaties in Learning Units 5 and 20. Regional powers such as India and Pakistan have also entered into bilateral agreements to stabilise their security relations.
The challenge of bilateral arms control is to overcome the dilemma of mistrust and fear that the opponent might cheat and gain a unilateral advantage from the agreement. To counter this risk, monitoring and verification measures must be agreed, although these in turn require each party to be transparent regarding their own capabilities and deployment plans, at least to a certain extent.
Multilateral arms control
Multilateral arms control refers to agreements, treaties or measures of three or more countries that regulate, reduce or eliminate certain weapon systems or military activities. Their goal is usually to increase global or regional security and stability, to prohibit or restrict the proliferation of dangerous weapon systems. The main challenge of multilateral arms control is that parties of different sizes and strengths, ideological orientations and military power must agree on joint measures. These problems plagued the ultimately unsuccessful Mutual and Balanced Force Reduction in Europe (MBFR) talks during the Cold War, in which the member states of NATO and the Warsaw Pact engaged for 16 years. It was only at the end of the Cold War that limits for the number of heavy weapon systems that could be stationed between the Atlantic and the Urals were agreed in the CFE Treaty of 1990. Similar difficulties were encountered by the UN Conference on Disarmament, which dates back to an agreement between the United States and the Soviet Union in 1962 and has not had any major successes since the ban on chemical weapons in 1997. The most important multilateral arms control agreement is undoubtedly the Nuclear Non-Proliferation Treaty (NPT), which, as mentioned above, restricts the possession of nuclear weapons and obliges the nuclear weapon states to negotiate nuclear disarmament in good faith.
The current crisis of the NPT is a prime example of how the issues of different state interests, the lack of universality due to unequal and incomplete participation, and difficulties of compliance and enforcement become particularly noticeable in multilateral arms control negotiations. Yet, the increasing multipolarity of the international system requires a turn towards precisely such multilateral arms control in the future.
Legal status
In terms of International Relations theory, arms control is a collaboration game. This means that even after an agreement has been reached, all parties have an incentive to exploit others’ willingness to cooperate by cheating or free-riding. To reduce this risk, arms control agreements need strong provisions for monitoring compliance and sanctioning misbehaviour. This is the reason why many arms control proponents favour strongly institutionalised arms control regimes based on international treaties duly ratified by national legislators. The expectation is that legally negotiated agreements reduce ambiguities, specify possible sanctions, increase domestic political commitment and thus ensure greater willingness to comply.1
Non-binding agreements
However, not all arms control agreements are based on international treaties. Some are informal or, as jurists say: non-binding agreements. They might still be politically binding, but have no legal basis on which states could demand or enforce compliance. There are a number of reasons why states might prefer informal to formal agreements:
- They might want to reach an agreement quickly, for example in the event of an impending crisis or where new technologies require swift action.
- They might be seeking to avoid subsequent renegotiation if a situation is volatile and complex.
- They might want to avoid a ratification process if the agreement is controversial domestically.
- They may want to avoid overly stringent requirements and keep the option of withdrawing from the agreement open in the event that conditions change.
But flexibility has its price. The downside of informal agreements is their lack of legal obligation.2
Behavioural arms control
In addition to informal arms control agreements that have been negotiated but never legally formalised, such as the CTBT (which has never been ratified), there is another type of arms control that is even less tangible because it does not even arise from negotiations or talks, but from political practice, tacit understandings and shared expectations. This so-called behavioural arms control consists of emergent customs and tacit norms that constrain presumably inappropriate military behaviour, such as naval operations conducted too close to another party’s shores, to reduce the risk of accidental escalation.
Lack of trust
While international law can play an important role in arms control, not all arms control agreements need to be legal in character. International law itself is based on an obligation to comply with international rules. Where trust between states has been so severely undermined that even the non-legal foundations of international law are not recognised, less formalised forms of cooperation must be used to ensure basic arms control.
Preventive arms control
Arms control can start at different points in time during the military acquisition process. Most arms control agreements were negotiated only after weapons had already been deployed. However, it is also possible to regulate weapons even before they enter the production and deployment phase. This is known as preventive arms control. 3
Source: Grübelfabrik (CC BY NC)
Because states are usually reluctant to agree to limitations on military technology that may provide them with an advantage, preventive arms control has been rare. Since the United States withdrew from the Anti-Ballistic Missile (ABM) Treaty in 2002, there is only one arms control agreement left that could be reasonably considered preventive: the Outer Space Treaty, which prohibits the deployment of weapons of mass destruction in space (for more details on this see Learning Unit 8).
Cooperation vs coercion
Arms control is usually seen as a form of cooperation, where actors reach some form of compromise or agree on joint action regarding their military programmes. However, power and pressure have always played a role in arms control negotiations and subsequent regimes. What is more, since the end of the Cold War, non-cooperative or coercive arms control has emerged as a distinct field of global governance.4
Coercive arms control is the exercise of political, economic or military power by states, groups of states or international organisations in order to limit or prohibit another state or group of states or non-state actors to acquire, develop or use certain weapon systems. Coercive arms control can be applied with a broad mandate from an international organisation, as was the case with the UN’s economic sanctions against North Korea used to pressure the country to abandon its nuclear weapons programme. However, so-called ‘coalitions of the willing’ have also used military force without such a mandate, e.g. in Libya and Iraq (2003) to compel them to dismantle their WMD capabilities after sanctions were deemed ineffective. Even Israel’s air strikes against nuclear facilities in Iraq (1981) and Syria (2007) have been justified as coercive arms control measures.
If carried out without proper legal justification, coercive arms control measures violate the principles of sovereignty and the non-use of force and can undermine regional and global stability. Their effectiveness has also been questioned, since coercion tends to provoke resistance. However, when states systematically violate international treaties or humanitarian norms, some form of coercive arms control may be necessary to maintain the international order.
Factors for success
Whether arms control is successful or not depends on a variety of factors, and there is no agreement on the conditions under which arms control will automatically lead to certain success. However, there are factors that influence the chances of successful arms control in one direction or another. Some of the most important are:
International politics
Succesful arms control between major powers usually requires a shared understanding about their position in the international order. Moreover, it is important that they are able to manage key regional questions underpinning their geopolitical competition, such as the division of Europe into two blocs during the Cold War.5
Domestic politics
Besides the international political environment, the domestic political landscape also needs to be conducive to arms control. This often means that there must be a willingness to limit military spending as a means to reduce pressure on the overall budget. In democratic societies such as the United States, this pressure has primarily come from U.S. Congress, but also from civil society. In the autocratic systems of Russia and China, however, there are no counterparts to these entities.6
Leadership
Individual leaders and their conceptions about the world can also play an important role for the success of arms control. American president Ronald Reagan and Soviet leader Mikhail Gorbachev, for example, shared a common understanding about the dangers of nuclear war, paving the way for significant reductions in the two states’ nuclear arsenals at the end of the Cold War. If Gorbachev, who was open to reforming the USSR and rethinking its role in the international system, had not become leader of the Soviet Union in 1985, the Soviet Union might never have negotiated the INF Treaty with the United States. In a similar vein, Gorbachev needed a partner in the White House who was also open to negotiating nuclear reductions and found him in the form of US president Ronald Reagan.7 The INF Treaty is therefore a good example of the importance of leadership in arms control.
Technology
Technology is another important factor that impacts the prospects of arms control. It is widely believed that arms control is most challenging when offensive technologies have the upper hand, while defensive technologies are conducive to arms control. Yet, it is extremely difficult to categorise weapons as either offensive or defensive because most of them can be used for both purposes. Nevertheless, it is probably fair to say that the prospects of successful arms control hinge on the perceived military utility of a technology, regardless of whether it may be used offensively or defensively. The substantial reductions in US tactical nuclear weapons after the Cold War, for instance, were driven to a not insignificant extent by the realisation of military leaders that these weapons would be an obstacle to conventional military dominance on the battlefield.8
The nature of the weapon
Certain weapons being considered particularly inhumane or morally repugnant can also help to spur arms control initiatives. Anti-personnel mines, for example, were long considered to be militarily useful. Yet, NGOs succeeded in bringing about a change in thinking by focusing on the human suffering these weapons cause, particularly for a country’s civilian population. The result was the Ottawa Treaty, also known as the Mine Ban Treaty. Only a few countries – including major military powers – still refuse to sign this treaty. Cluster munitions were banned under the Oslo Convention for similar reasons. However, this framing does not always succeed. Despite strong campaigns against armed drones in the 2010s, for instance, states considered the military benefit of these weapons to be so great that no restrictions on their use, let alone a ban, could be enforced internationally.
Moreover, the increased likelihood of a high-intensity military conflict on NATO’s eastern flank after Russia’s full-scale invasion of Ukraine has prompted some governments to reconsider their position regarding the Mine Ban Treaty and the Convention on Cluster Munitions. In 2024, Lithuania decided to withdraw from the Convention on Cluster Munitions while also contemplating a withdrawal from the Mine Ban Treaty – and Finland, too, with its long border to Russia, is considering the same.
Another factor that is often referred to as a prerequisite for successful arms control is trust. But is it really as important as is often asserted? In the following section, you will learn more about the role of trust in arms control.
Footnotes
-
Weber, Steve. 1991. Cooperation and Discord in U.S.-Soviet Arms Control, vol. 166. Princeton University Press, https://doi.org/10.2307/j.ctt7zv7m4. ↩
-
Lipson, Charles. 1991. “Why Are Some International Agreements Informal?”, in: International Organization 45 (4): 495–538. ↩
-
Altmann, Jürgen et al. 1998. “Preventive Arms Control as a Prerequisite for Conversion of Military-Related R&D”, in: Reppy, Judith (ed.), Conversion of Military R & D. London: Palgrave Macmillan UK, 255–71, https://doi.org/10.1007/978-1-349-14886-8_17. ↩
-
Daase, Christopher/Meier, Oliver. 2012. “The Changing Nature of Arms Control and the Role of Coercion”, in: Arms Control in the 21st Century. Routledge, 233–41. ↩
-
Barrie, Douglas/Wright, Timothy (eds). 2022. MDI Missile Technology: Accelerating Challenges. London: The International Institute for Strategic Studies, https://www.iiss.org/publications/strategic-dossiers/mdi-missile-technology-accelerating-challenges. ↩
-
Barrie and Wright. ↩
-
Colbourn, Susan. 2023. “Arms Control and Deterrence: The Euromissiles, Then and Now”, HCSS Programme on Strategic Stability: Deterrence and Arm Control. The Hague: The Hague Centre for Strategic Studies, March, 4, https://hcss.nl/wp-content/uploads/2023/03/03-Colbourn-Arms-Control-and-Deterrence-Euromissiles.pdf. ↩
-
Koch, Susan J. 2012. The Presidential Nuclear Initiatives of 1991-1992, Center for the Study of Weapons of Mass Destruction Case Study ↩