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Joint Air & Space Power Conference 2017

Conventional Arms and Nuclear Peace

By Christine Leah and Adam B. Lowther, Former Chauncey Postdoctoral Fellow in Director, School of Grand Strategy, Yale University Advanced Nuclear Deterrence Studies

What many in the arms control community fail to appreciate, understand, or adequately analyze is how conventional force imbalances play into a state’s security dilemma. Conventional arms imbalances generally – and US conventional military superiority specifically – are as much potential drivers of nuclear proliferation and geostrategic instability as nuclear weapons are. American preponderance in power-projection capabilities has in the past influenced some countries to acquire nuclear weapons as a deterrent against US intervention. There has been far less effort expended on exploring the relationship between conventional arms and nuclear proliferation than on nuclear arms and nuclear proliferation. In part, this may be because the spread of conventional weapons is viewed as a serious problem in its own right, possessing its own dynamics and its own bureaucratic and academic constituencies. However, conventional imbalances are just as important in understanding the threat perceptions that lead states to acquire nuclear weapons.

Why Conventional Military Balances Are Important

The relationship between the size of a state’s arsenal and the resultant proliferation consequences is complex and, at best, only one part of the proliferation puzzle. For the past quarter-century, the US military’s mastery of precision warfare has provided it with a significant advantage over its prospective rivals. Both China and Russia are working to offset this advantage, in part by developing their own competing capabilities. However, according to recent research by national security analyst Matthew Kroenig, there is no clear relationship between US nuclear force posture and proliferation decisions by other states.1 Indeed, the connection may even be an odd proposition to make in the first place. That national leaders (aside from a Russian president) would stop to assess US nuclear policy or the size of the US nuclear arsenal before making decisions about nuclear proliferation is a tenuous assertion. Kroenig’s research addresses an important question, but it does not analyze the role that the geographical deployment of US military forces has on a country’s threat perceptions. In fact, states are more likely to confront, and therefore fear, America’s conventional capabilities.

In the interim, the Russians in particular are seeking to offset the American advantage in precision-guided munitions by modernizing their nuclear arsenal and changing nuclear doctrine – even stressing nuclear escalation as a de-escalation mechanism. What appears clear is that both nuclear and nonnuclear nations see the prospects for conventional conflict with the United States as a losing proposition. For Russia and China, threatening to escalate their way out of a conventional loss is clearly an attractive option that Russian nuclear doctrine suggests is at the forefront of Pres. Vladimir Putin’s strategic planning.2 For nonnuclear states, acquiring nuclear weapons may be perceived as the only viable deterrent against American aggression. In general, nuclear weapons are largely seen as an offset to superior conventional capabilities possessed by an adversary. With Iraq’s weapons of mass destruction (WMD) ambitions, for instance, evidence suggests that Saddam Hussein, from the mid and late 1970s onward, was interested in nuclear weapons for two reasons: deterrence vis-à-vis enemies like Israel and Iran and considerations of national prestige.3 However, Hussein also wanted nuclear weapons as a means of enabling conventional attacks on Israel:

When the Arabs start the deployment, Israel is going to say, ‘We will hit you with the atomic bomb.’ So should the Arabs stop or not? If they do not have the atom, they will stop. For that reason they should have the atom. If we were to have the atom, we would make the conventional armies fight without using the atom. If the international conditions were not prepared and they said, ‘We will hit you with the atom’, we would say, ‘We will hit you with the atom too. The Arab atom will finish you off, but the Israeli atom will not end the Arabs.’4

The acquisition of nuclear weapons by a weaker state significantly complicates the decision-making calculus of a militarily superior state. For these reasons, power-projecting states fear nuclear proliferation to both allied and enemy states.5 This is a point worth underscoring and one that is often overlooked when nonproliferation is discussed and its rationale and purposes debated. These factors demonstrate that the ‘more may be better’ view of nuclear weapons proffered by political scientist Kenneth Waltz is entirely relevant and accurate.6 Waltz famously argued that more nuclear weapons in the world would tend to increase deterrence among states. That logic is turned on its head in a world with far fewer nuclear weapons and a greater reliance on conventional systems, which may actually be destabilizing. This was true even before the advent of the atomic bomb. The awesome destructive power of nuclear weapons tended to overshadow the failure of conventional deterrence in the decades and centuries preceding the first use of nuclear weapons.7 Thomas Schelling, an economist and foreign policy scholar, also argued very specifically that more nuclear weapons might enhance strategic stability by increasing the survivability of a nation’s nuclear forces.8 Because states might be more risk acceptant with conventional forces and concepts of first and second strikes are much less well defined in the conventional realm, stability was much more fragile in the pre-nuclear age and would likely prove fragile in a world with fewer, or zero, nuclear weapons. Advocates of a world free of nuclear weapons often overlook this point. A world with fewer nuclear, but more conventional, forces is likely to bring forth new dynamics for arms races, which increase the likelihood of disputes and wars.9 Reducing or eliminating nuclear weapons does not remove proliferation problems from the agenda. Might we fear arms races in the second conventional age less because of the sub consequences of an advanced conventional missile system, or should we fear it more because of the lower threshold to the use of armed force that might be involved? A world not anxious about nuclear proliferation is more likely to be anxious about the proliferation of advanced conventional systems. In that world, the knowledge that war might escalate to the use of an immediate and devastating nuclear strike is gone. This also raises new issues influencing the extent to which a conventional war may be more controllable than a nuclear one. As Lawrence Freedman, the doyen of British strategic studies, writes, ‘In principle, denial is a more reliable strategy than punishment because, if the threats have to be implemented, it offers control rather than continuing coercion. With punishment, the [adversary] is left to decide how much more to take. With denial, the choice is removed.’10

Nuclear Reductions, Nonproliferation, and Disarmament

Nuclear abolitionists have very different views on the nature of deterrence. Their efforts are based largely on a fundamental ideological dislike of nuclear weapons rather than a deep understanding or appreciation of them. Global nuclear disarmament, if considered in a vacuum, would make the world safer for US conventional power projection but would not necessarily promote strategic stability. This observation is made repeatedly by Russian and Chinese analysts, who clearly understand American conventional superiority. On this basis an argument can indeed be made that global disarmament disproportionately benefits the United States, not regional or global competitors like Russia and China. The effects of conventional capabilities are certainly a neglected topic when compared to the focus on nuclear arms control over the past seven years. They are generally said to bear, or lack, significance in comparison to WMDs. But does this argument still hold in a world with no nuclear weapons? A great deal of analysis is still needed to assess whether and how reductions could be managed to the point that no nuclear-armed state has more than a minimum deterrent. For even further reductions to occur, the process would necessarily have to be multilateral, including China, India, and Pakistan. While China and other states have indicated that they would potentially be willing to enter into negotiations once the United States and Russia reduce their arsenals, they have not specified at what level of forces this might conceivably take place. In any case, the process would involve complex calculations of deterrence equations involving changing sets of multiple actors as well as conventional imbalances that are, again, a major source of concern for many countries that may find themselves at odds with the United States. For the ‘P5’ nuclear weapons states (those with permanent seats on the United Nations’ Security Council) such as Russia and China who are members of the Nuclear Nonproliferation Treaty (NPT), the issue of conventional imbalance compounds the difficulty they face in shaping the perception of some states who suggest that the P5 failed to take significant steps toward nuclear disarmament. Pakistan, for instance, has recently accused the United States and other countries of nuclear hypocrisy, with the Pakistani ambassador to the United Nations saying that a handful of nuclear-weapon states advocate abstinence for others but are unwilling to give up their large inventories of nuclear weapons or cease modernization efforts. The ambassador also stressed that double standards were not only evident on nuclear issues but also in the area of conventional arms: ‘While professing strict adherence to responsible arms transfers, some powerful states continue to supply increasing numbers of conventional weapons in our region, thereby aggravating instability in South Asia.’11 Indeed, from the Pakistani perspective, the international community does not give enough attention to the issue of vertical proliferation (arms buildup). Certainly, it should come as no surprise that Pakistan continues to stress the importance of nuclear weapons in acting as a deterrent to perceived Indian conventional military superiority.12

Pakistan has made efforts at addressing issues of conventional force imbalances with India in the past, but New Delhi has traditionally dismissed these efforts, instead focusing on its larger regional competitor, China.13 The problem in South Asia is therefore at least a trilateral one. However, the issue speaks to a much larger problem, and that is multilateral conventional arms control. If the India-Pakistan strategic situation offers any lesson, it is that weaker states (such as Pakistan) may desire to develop a ‘great equalizer’ to achieve the security that they cannot find through traditional (conventional) means.

With the United States and Russia undertaking a 90 percent reduction in their nuclear arsenals since the end of the Cold War, it is fair to say that these efforts have promoted neither goodwill nor a peaceful posture in countries like China or North Korea. We are not suggesting that American nuclear force reductions have pushed Beijing to expand its antiship ballistic missile inventory, place multiple warheads on its DF-41 ballistic missiles, build artificial islands with deployed military capabilities, or build bases in northern Africa. Nevertheless, it does show that there is little evidence to suggest that nuclear cuts necessarily lead to a more peaceful security environment. If anything, regional and global security evolve independently of the size and shape of one country’s nuclear arsenal. North Korea, in particular, has pursued a nuclear weapons program as a means of countering American conventional superiority, paying little or no attention to the United States’ declining nuclear arsenal.

Conventional Arsenals, Crisis Stability, and Arms Race Stability

Nuclear reductions have important consequences for both crisis stability and arms race stability. Conventional forces differ tremendously from nuclear forces in the way they are organized and operate and in their destructiveness. These distinctions influence the way in which arms-control arrangements aimed at conventional arms-race stability and crisis stability must be conceptualized in a world free of nuclear weapons but safe for conventional conflict. To be highly destructive, conventional forces need to be used en masse. Their successful application requires well-organized cooperation between many military units, often between different types of military forces (land, air, naval, cyber, and space), and, due to the globalization of conflict, also the participation of several allied states granting military support and access. Conventional forces most often seek military victory, which requires they first defeat adversarial forces before the political objectives of the conflict can be achieved. Also, to be militarily effective, conventional forces need up to date technology and well-trained troops that are capable of effectively employing weapons of war.

Crisis stability is a term that was perfected in its use during the nuclear age. Crisis stability aims at developing incentives for using the lowest level of military force possible – all while seeking to prevent escalation. It also seeks to control the emotions that are prevalent in conflict, providing procedures to cope with a crisis. Nuclear reductions and disarmament may make a paradoxical and undesired contribution; reducing expected levels of death and destruction if war comes might actually increase the probability of the onset of war. Even if two states went to war, one would expect the nuclear sword of Damocles to incentivize them to end the conflict as soon as possible. In addition, the historical record clearly shows there is not the same taboo or norm against using conventional missiles and bombers as there is against using an atomic version.14 Not a single nuclear warhead has been delivered by any delivery system since 1945. By contrast, over the past 45 years, ballistic missiles were employed in at least six different conflicts: the Egyptian and Syrian missile attacks on Israel in the 1973 Yom Kippur War, the 1980–88 war between Iraq and Iran, the Afghan civil war of 1988–91, the 1991 Persian Gulf War, the Yemen civil war of 1994, and the 2003 US-led invasion of Iraq. Indeed the duration and controllability of a war becomes important here. As antinuclear advocate Randall Forsberg admits,

‘The main role of nuclear weapons has always been to deter conventional war among the world’s “big powers” (the USA, the USSR, the UK, France, West Germany, China, and Japan) by posing a clear risk that such a war would escalate to nuclear war. If ballistic missiles were abolished, raising again the prime strategic question of the 1950s – could a conventional war be fought without going nuclear, and if it went nuclear, could it be won? – it would diminish nuclear deterrence of conventional war.’15 (emphasis in original)

The fog of war could become much thicker. Even if lower-yield nuclear weapons were used, they could still significantly disrupt command, control, communication, and intelligence. In the conventional world this would be less of an issue because of the smaller level of destruction, over a much more protracted amount of time, thus enabling more time to react. In the nuclear age, time becomes much more compressed. Moreover, assuming that deterrence was still desirable, states would have to rethink how to reorient their forces toward achieving a conventional second-strike capability. This might lead to a different type of arms race. This concept was already present before the advent of the bomb, in discussions about the importance of airpower and having enough aircraft to deter aggression among European states.16 All these issues raise the importance of focusing on conventional arms control as much as nuclear reductions, especially in the Asia-Pacific.

Arms race stability aims at lowering incentives to further build up military forces. Thus we might conceivably ask: if the United States and Russia reduce their nuclear arsenals to a few hundred warheads each – and other nations to a few dozen – might we see a nonnuclear arms race to fill a nuclear void?17 As the 2010 Nuclear Posture Review states, ‘fundamental changes in the international security environment in recent years – including the growth of unrivaled US conventional military capabilities [and] major improvements in missile defenses … enable us to fulfill … objectives at significantly lower nuclear force levels and with reduced reliance on nuclear weapons … without jeopardizing our traditional deterrence and reassurance goals.’18 If one accepts this statement, and if opponents of nuclear modernization are truly concerned about reducing global instability, they should be urging the administration to cancel and eliminate a number of conventional capabilities that are far more concerning to our adversaries. Granted, such a position is irrational, but if stability is the key then this is the logical position to hold. Indeed, even with successful elimination of nuclear weapons, the tasks of strategic deterrence, extended deterrence, and arms control do not go away. Instead, they become more difficult to manage. This is especially true for conventional arms control, because nuclear weapons tend to make deterrence much easier, or so the historical record would seem to indicate. If one argues for further nuclear reductions and nuclear disarmament, then one needs to be responsible and also think seriously about conventional arms control. Conventional imbalances and any remaining system of deterrence would increasingly become the focus of deterrence and would serve as the source of instability.19 This is especially true because, in many instances, the imbalance and insecurity of a conventional-only world have remained obscured during the nuclear age.20

With Article VI of the NPT obliging nuclear-weapon states to work toward general and complete disarmament of nuclear weapons, would such a treaty be required or feasible in a conventional world? This possibility raises an important question: to what extent should nuclearweapon states focus on reducing their arsenals as a precondition for conventional disarmament? We have tended to think that it would first be a good idea to reduce nuclear weapons before reducing conventional forces. However, nuclear weapons are but one component of the overall military balance among states. In an age without nuclear weapons, it is also conceivable that deterrence relationships will simply not work without boosting some aspects of conventional arsenals. The more – maybe – better logic that Schelling (and others) applied to nuclear weapons may also carry into an entirely conventional era. That is, fewer nuclear weapons in the world would likely entail more conventional forces to compensate, which would not necessarily be a stabilizing development. For advocates of ‘global zero’, the implications of a world free of nuclear weapons are assumed to be inherently positive. However, the reality of such a world may be far less positive because the psychological effect achieved by the understood destructive power of nuclear weapons will no longer push risk-acceptant national leaders to allow caution to prevail. Given that no current leader of a nuclear-weapon state was even alive prior to the development of the atomic bomb, the security and stability of a nuclear-free world should not be taken for granted. Instead, much more work is required to understand the implications of such a fundamental change to a proven and stable approach to constraining great-power conflict.


If the past offers any lessons for the future, it is not unreasonable to believe that a world free of nuclear weapons is a world in which standing armies grow larger, defence expenditures (as a percentage of gross domestic product) increase, and conflict becomes more frequent as the perceived risks to a nation and its leaders decline. National leaders are not always rational, because they do not effectively weigh costs and benefits or risks and rewards, which would lead them to overvalue the prospect of a loss and undervalue the prospect of a gain. The certain loss caused by any prospective use of nuclear weapons has caused decision makers to exercise great restraint when contemplating the prospective use of force.21 History appears to suggest that, to some degree, nuclear weapons do cause decision makers to see the use of nuclear weapons as ensuring losses, with few gains – causing restraint. Thus, eliminating nuclear weapons may well reduce perceived risks and increase perceived gains from fighting – making the world safe for conventional conflict. Such a state of affairs would not have the same absolute risk associated with it that nuclear warfare poses (that of total annihilation), but it would increase the risks of proliferating conflict, which may lead to a dramatic increase in conflict-related casualties. Efforts to bring nuclear abolition to fruition may have an unintended consequence that has been given too little consideration by those who have made it their goal to rid the world of nuclear weapons. Too often, opponents of the nuclear arsenal fail to go beyond their desired end state to understand the consequences of such a world. Would America and the rest of the world really be better off without nuclear weapons holding great-power conflict in check? Such a discussion is strikingly absent from the debate. Perhaps it is time for advocates of nuclear abolition to provide a compelling description of the world that is to come should they succeed in further reducing or eliminating the nuclear arsenals of the great powers.

1. Matthew Kroenig, ‘US Nuclear Weapons and Non-Proliferation: Is There a Link?’, Journal of Peace Research 53, no. 2 (Mar. 2016): 166–79,
2. ‘Russian General Calls for Preemptive Nuclear Strike Doctrine against NATO’, Moscow Times, 3 Sep. 2014,
3. Scott D. Sagan, ‘Why Do States Build Nuclear Weapons? Three Models in Search of a Bomb’, International Security 21, no. 3 (Winter 1997): 54–86,
4. Quoted in Hal Brands and David Palkki, ‘Saddam, Israel, and the Bomb: Nuclear Alarmism Justified?’, International Security 36, no. 1 (Summer 2011): 133–66,
5. Matthew Kroenig, Exporting the Bomb: Technology Transfer and the Spread of Nuclear Weapons (Ithaca, NY: Cornell University Press, 2010), 3.
6. Kenneth Waltz, ‘The Spread of Nuclear Weapons: More May Be Better’, Adelphi Papers, no. 171 (London: International Institute for Strategic Studies, 1981),
7. ‘Conventional Strike on Russia May Prompt Nuclear Response’, Nuclear Threat Initiative (website), 12 Dec. 2013,; TV-Novosti, ‘“Deterrence Not Arms Race”: Russia Hints it May Develop Rival to US Prompt Global Strike’, RT News, 11 Sep. 2014,; and Andrew Futter and Benjamin Zala, ‘Advanced US Conventional Weapons and Nuclear Disarmament: Why the Obama Plan Won’t Work’, Nonproliferation Review 20, no. 1 (Mar. 2013): 107–22,
8. Thomas Schelling, Arms and Influence (New Haven, CT: Yale University Press, 1996), 145–51.
9. Douglas M. Gibler, Toby J. Rider, and Marc L. Hutchison, ‘Taking Arms against a Sea of Troubles: Conventional Arms Races during Periods of Rivalry’, Journal of Peace Research 42, no. 2 (Mar. 2005): 131–47,; Toby J. Rider, ‘Understanding Arms Race Onset: Rivalry, Threat, and Territorial Competition,’ Journal of Politics 71, no. 2 (Apr. 2009): 693–703,; and George W. Downs, David M. Rocke, and Randolph M. Siverson, ‘Arms Races and Cooperation’, World Politics 38, no.1 (Oct. 1985): 118–46,
10. Lawrence Freedman, Deterrence (Cambridge, UK: Polity Press, 2004), 39.
11. ‘At UN, Pakistan Slams “Nuclear Doublespeak”’, Pakistan Today, 6 Apr. 2016,
12. See also, for instance, Russian concerns over US high-precision conventional weaponry. Sharon Squassoni, Andrew C. Kuchins, Steven Pifer, and Guy B. Roberts, ‘CSIS Track-II Dialogue on Limiting Non-Strategic Nuclear Weapons’ (panel, Center for Strategic and International Studies, Washington, DC, 4 Sep. 2015),
13. Feroz H. Khan, Eating Grass: The Making of the Pakistani Nuclear Bomb (Stanford, CA: Stanford University Press, 2012).
14. See, for example, George Ball, ‘The Cosmic Bluff’, New York Review of Books, 21 Jul. 1983; John Lewis Gaddis, The Long Peace: Inquiries into the History of the Cold War (Oxford: Oxford University Press, 1987), chapter 5; T. V. Paul, ‘Nuclear Taboo and War Initiation in Regional Conflicts’, Journal of Conflict Resolution 39, no. 4 (Dec. 1995): 696–717,; and Nina Tannenwald, ‘The Nuclear Taboo: The United States and the Normative Basis of Nuclear Non-Use’, International Organization 53, no. 3 (Summer 1999): 433–68,
15. Randall Forsberg, ‘Abolishing Ballistic Missiles: Pros and Cons’, International Security 12, no. 1 (Summer 1987): 194,
16. See George H. Quester, Deterrence Before Hiroshima: The Airpower Background of Modern Strategy (New York: John Wiley & Sons, 1966), 62–64.
17. This refers not just to a sustained buildup of defence capabilities by two states but also to a situation where there is substantial evidence of action-reaction dynamics. Desmond Ball, ‘Arms Modernization in Asia: An Emerging Complex Arms Race’, in The Global Arms Trade: A Handbook, ed. Andrew T. H. Tan (London: Routledge, 2010), 30–51; Theresa Clair Smith, ‘Arms Race Instability and War’, Journal of Conflict Resolution 24, no. 2 (Jun. 1980): 253–84,; Desmond Ball, Politics and Force Levels: The Strategic Missile Program of the Kennedy Administration (Berkeley: University of California Press, 1980); Harvey M. Sapolsky, US Defense Politics: The Origins of Security Policy (New York: Routledge, 2008); Harvey M. Sapolsky, The Polaris System Development: Bureaucratic and Programmatic Success in Government (Cambridge, MA: Harvard University Press, 1972); Richard A. Bitzinger and J. D. Kenneth Boutin, ‘China’s Defence Industries: Change and Continuity’, in Rising China: Power and Reassurance, ed. Ron Huisken (Canberra: Australian National University Press, 2009), chapter 10; and Richard A. Bitzinger, ‘A New Arms Race? Explaining Recent Southeast Asian Military Acquisitions’, Contemporary Southeast Asia 32, no. 1 (Apr. 2010): 50–69,
18. US Department of Defense, Nuclear Posture Review (Washington, DC: Department of Defense, 2010), v,
19. See also Christopher Ford, ‘A New Paradigm: Shattering Obsolete Thinking on Arms Control and Nonproliferation’, Arms Control Association (website), 3 Nov. 2008,; and ‘NORAD Commander: Our Missile Defense Strategy Won’t Work’, Sputnik News, 12 Aug. 2015,
20. Christine M. Leah, ‘Deterrence and Arms Control in a Second Conventional Age’, Comparative Strategy 34, no. 5 (2015): 401–21,
21. Amos Tversky and Daniel Kahneman, ‘Advances in Prospect Theory: Cumulative Representation of Uncertainty’, Journal of Risk and Uncertainty 5, no. 4 (1992): 297–323,


The views and opinions expressed or implied in SSQ are those of the authors and are not officially sanctioned by any agency or department of the US government. We encourage you to send comments to:

Christine M. Leah is a former Chauncey Postdoctoral Associate at Yale University, USA. She was previously a Stanton Postdoctoral Fellow in Nuclear Security at MIT, USA. She completed her PhD at the Strategic and Defence Studies Centre of the Australian National University. She is the author of Australia and the Bomb (2014).

Adam Lowther is a research professor and director of the Center for Academic and Professional Journals at the Air Force Research Institute (AFRI) at Maxwell Air Force Base in Alabama. He has published in the New York Times, Boston Globe, Joint Forces Quarterly, Strategic Studies Quarterly, and a variety of other journals and outlets.