Conclusion

If the fear of nuclear war has faded as the Cold War recedes into the misty past, we may need to remind ourselves of what these weapons can do. At least five of the nine countries that currently possess nuclear weapons can deliver thermonuclear warheads, each with the explosive equivalent of several hundred thousand tons of TNT, nearly halfway around the Earth.1 The intercontinental ballistic missiles (ICBMs) and submarine-launched ballistic missiles (SLBMs) that would deliver them at this range are called “strategic” because they can reach into an adversary's homeland to destroy leadership, military, infrastructure, or civilian targets. Warheads on different missiles are characterized by their yield (explosive energy) and their accuracy. Estimates in the open literature suggest that the United States, for example, can deliver a 455 kiloton warhead launched from a Trident ballistic missile submarine over six thousand miles to detonate within the length of a football field of its target.2 The yield of 455 kilotons means that the energy released would equal the explosive energy of 455,000 kilograms (about one million pounds) of high explosive (TNT), which would be more than thirty times the energy released by the nuclear weapon detonated by the United States over Hiroshima during World War II. Depending on the relative location of the submarine launching the SLBM and its intended target, the time between the launch and the detonation of the warhead could be as short as six to ten minutes.3 An adversary might have only that much warning time to recognize that an attack was underway and react.Some Russian and Chinese strategic missiles are thought to carry warheads of even larger explosive yields. For example, the Russian SS-19 Mod 3 ICBM carries six independently targetable warheads (MIRVs) that reportedly have a yield as high as 750 kilotons.4Figure 1 shows the effects of one such 750-kiloton warhead exploding 1 mile (1.6 kilometers) above New York City, centered on Midtown Manhattan.5 The four concentric rings in the figure illustrate the effects of the explosion. Moving outward from the point of detonation: Within the first ring (radius 2.5 kilometers) the blast is so strong that even heavily built concrete buildings are demolished. Virtually every person within this area is killed in the blast. This ring extends entirely across the island of Manhattan from the East River to the Hudson. The second ring (radius 5.7 kilometers) reaches into New Jersey and the boroughs of Brooklyn and Queens. It marks the distance out to which residential buildings collapse. At this distance, “injuries are universal and fatalities are widespread.” The third ring (radius 11 kilometers) shows the effects of the immediate thermal radiation (high intensity ultraviolet, visible, and infrared light emitted by the explosion). Out to this distance, anyone with a line of sight to the detonation suffers third-degree burns to exposed skin. Finally, the fourth ring (radius 15 kilometers) marks the distance out to which windows shatter, with resulting injuries from flying glass. Overall, more than 1.8 million people would be killed nearly instantly, and over 2 million more immediately wounded. These numbers ignore the effects of frestorms–massive urban fires driven by hurricane-force winds that may result from the nuclear detonation6–as well as longer-term radiation and fallout. Of course, many hospitals and firehouses would be destroyed, and many medical personnel immediately killed, limiting the life-saving potential of first-responders.These results are for a single large strategic warhead. Under the 2011 New START arms control treaty, Russia and the United States agreed to reduce their numbers of deployed strategic warheads to 1,550 on each side.7 China, France, and the United Kingdom have smaller numbers of warheads on missiles, estimated at about 290, 300, and 225 warheads, respectively.8 In a nuclear war, or a conventional war that escalated to the use of strategic nuclear weapons, many–perhaps hundreds or more–such detonations might take place.This must never be allowed to happen. One way to try to ensure that it never does is to threaten nuclear-armed adversaries with nuclear retaliation from forces that would credibly survive an initial attack (the “first strike”). Potential attackers would then presumably be deterred from launching a first strike because they would feel certain to suffer devastating nuclear retaliation.9 Yet this deterrent posture carries with it an inescapable, perhaps small but difficult to quantify, possibility of inadvertent or mistaken nuclear war.10Another way to try to ensure that the worst never happens is to eliminate all nuclear weapons worldwide. But this approach raises its own challenges. One is how to reduce and then eliminate nuclear weapons with sufficient verification that all countries could feel confident that no weapons were hidden in violation of the disarmament agreements. A second is that weapons know-how cannot be unlearned and relevant capabilities fully undone, so that in a major war or political crisis, there could be pressure to recreate rapidly and perhaps preemptively use nuclear weapons. That is, a world of zero nuclear weapons could prove dangerously unstable. Experts have dedicated much attention to these challenges, but they are far from solved.11 At the same time, as this volume of Dædalus has highlighted, a future world in which stability is preserved through nuclear deterrence also faces considerable known and unknown challenges.But there are other possible security catastrophes that states also wish to prevent: for example, full-scale conventional war among the major powers. World War II resulted in the deaths of over sixty million people.12 The major powers have not waged total war against one another since 1945, even if many other smaller conflicts have been fought. There is more than one reason for this “Long Peace,” but it is likely that the existence of nuclear weapons has induced caution on the part of the major powers over being drawn into major war.13 The successful mating of fusion warheads to ICBMs or SLBMs has for this reason been termed the “nuclear revolution,” because the likelihood of major war among states equipped with these weapons has been, some argue, greatly reduced by removing any doubt in the minds of national leaders about the horrific outcome of such a war.14 Ballistic missile defense systems remain all but useless against more than a small number of incoming strategic warheads, so there is no reliable defense.15 Therefore, in a face-off among nuclear-armed states, rational leaders provided with competent technical information must recognize that their country lies open to destruction. There is no denying the devastating consequences of thermonuclear war. Since full-scale conventional war could escalate to nuclear war, rational leaders would not risk waging full-scale war on another ICBM- or SLBM-wielding thermonuclear power.16 And so, as some have argued, peace at this level has endured.Various countries at various times have claimed other vital uses for nuclear weapons. Before it gave up its small, indigenous nuclear weapons arsenal, apartheid South Africa imagined that threatening the use of its weapons would force the great powers to negotiate an end to any conflict that menaced it.17 Pakistan's senior generals have been clear that Pakistan would use nuclear weapons first if needed to repel a purely conventional Indian invasion.18 It seems likely that North Korea's Kim Jong-un views the threat to use his country's nuclear weapons as his ultimate guarantor of regime and personal survival.19 Finally, some countries, at least under certain leaders, may have pursued nuclear superiority (more nuclear missiles, with more nuclear warheads, say, than one's adversary) under the belief that this putative superiority in itself would confer other advantages or intimidate adversaries away from certain courses of action.20 Not unrelatedly, some countries may pursue nuclear weapons to protect themselves against the possibility of nuclear blackmail or coercion.21And so, we find ourselves in our current dilemma. Countries desire the security afforded by their own or their allies' nuclear weapons, but as long as these weapons exist, there remains a chance that they could be used in limited or even vast numbers. This could result from escalation in the context of an ongoing conventional war, with one side concluding it had no choice but to strike first; or it might result from an erroneous conclusion made under time pressure that another state has launched a nuclear attack; or from a miscalculation by a leader who is not realistically informed or who has rebuffed efforts to be so informed; or even via an irrational leader coming to power and making heinous decisions. It is sobering that since the end of World War II, nuclear adversaries have considered the use of nuclear weapons in preventive war, have explicitly or implicitly threatened the use of nuclear weapons, and, in the Cuban missile crisis, have come close to misjudgments that would have led to nuclear war.22 Concerns over escalation to the use of nuclear weapons are therefore justified by the historical record. At the same time, there has been no wartime use of nuclear weapons and no full-scale war between major powers since 1945.Nuclear-armed states have aimed to reduce the likelihood of the various pathways to nuclear weapons use by seeking to create conditions of strategic stability. Strategic stability is usually taken to include both crisis stability and arms race stability. Crisis stability means that even in a conventional war or faced with a possible nuclear attack, states would not use nuclear weapons for fear that such escalation would bring certain disaster. Crisis stability must be robust even against inadvertent or mistaken nuclear escalation. Arms race stability means that nuclear powers do not have incentives to pursue weapons or weapon deployments resulting in action-reaction cycles that undermine crisis stability.The goal of this volume has been to examine whether current directions in international affairs and a concomitant technological evolution are eroding strategic stability and placing the world at greater risk of nuclear weapons use–and if so, what might be done about it. In particular, this volume had its genesis in three particular concerns that appear to threaten strategic stability: the increasing complexity of nuclear relationships in a world of multiple and increasingly capable nuclear powers; the near-collapse of bilateral strategic arms control between the United States and Russia; and the development and possible deployment of new technologies whose characteristics overall seem likely to be destabilizing. Separately or combined, each of these trends could make escalation to nuclear weapons use more likely. These are wide-ranging multilateral challenges, but this volume has focused primarily on the triangular relationship among China, Russia, and the United States, with only occasional discussion of other nuclear powers. This reflects a practical decision to begin with these core relationships, not a belief that only those relationships matter. Subsequent work will expand this focus.23During the Cold War, countries looked to a variety of means to prevent escalation to nuclear war, without forsaking what they perceived as the security benefits of their nuclear arsenals. The dream of a successful defense against a large-scale nuclear attack never ended, but the technical reality remained that warheads launched from ICBMs and SLBMs were extremely difficult to intercept, and that an attacker's countermeasures were technically simpler and less expensive than a defender's interceptors.24 Absent a credible defense against strategic missiles, other approaches came to the fore.The least subtle of these was deterrence. In broad terms, deterrence in the nuclear context seeks to alter an adversary's cost-benefit calculation with respect to the use of nuclear weapons.25 Its most stark realization was in the condition of mutual assured destruction (MAD) between the United States and the Soviet Union. Once secure second-strike systems were in place, each side understood that full-scale nuclear war would mean mutual annihilation, regardless of who struck first. Each country was deterred, they hoped, from reaching for the nuclear trigger by a recognition that no conceivable benefit was worth this level of “assured destruction.”In less stark manifestations of deterrence, countries sought to supplement the threat of punishment with steps that would deny an adversary's efforts to achieve their goals in launching an attack: so-called deterrence by denial. For example, an adversary might imagine that small-scale nuclear weapons could be employed in limited fashion to secure a desired objective without leading to unacceptable further escalation. by capabilities that would an adversary from a to even greater nuclear weapons If nuclear weapons were used in a limited some that faced with an whose were might be deterred from to of nuclear deterrence, the United States and the Soviet and then Russia, in a variety of arms control that were intended to reduce the incentives side might have for to nuclear weapons Arms control sought to the of one both through technical into each capabilities and by in escalation through or would be less likely. in his for this several major arms control that these The sought to strategic missile defense deployments to each side a arms race that at its the that launching a first nuclear strike was credible to an defense against an adversary's The the Russian nuclear relationship by the range nuclear missiles in and and from the fear of nuclear destruction from a missile because of the could eliminate leadership, and or other with warning times much than those of The second Strategic Arms by the United States and the Russian in the of warheads from This would have reduced incentives for a first strike against missiles multiple treaty, never into these a of arms control by the desire to strategic than the to reduce the of nuclear as Yet there were also arms control that more with of than with the we are that the in the countries to to arms control were as political as they were an to nuclear in his in this this larger context for arms this be since such a might be to many in to survive over many in particular that arms the on the of was used by the United States and the Soviet their of at the of their allies' as and other have under the of its nuclear was a way to nuclear among those In particular, both the United States and the Soviet the as a to a nuclear The between deterrent and arms control in the of not with the end of the Cold if nuclear arms control is to have a future not only between the United States and Russia but among the other major nuclear it will only be if leaders it as a way to achieve larger as well as a nuclear of the nuclear one whose reach to some of the who the first was that such as deterrence and arms control could not strategic stability in and that international security would the of nuclear The recognition that nuclear weapons bring as well as stability was one of the which for their ultimate the Cold War, there was an and of efforts by of or on the part of states to pursue international security nuclear The in this volume on among and strategic approaches of the three leading United States, Russia, and attention to the views of states who find the strategic face-off for the of deterrence or to be and in their the on the of the in which the of attention on the part of the states to their and their on have to not bring into to nuclear weapons these approaches to strategic stability have been by the from the bilateral nuclear of the Cold War to more nuclear the trends we among increasingly capable nuclear-armed states, the of arms technological not in but may one another in in his for this that the effects of the from a nuclear weapons relationship to a nuclear can be in that of were the of from the strategic the more relationship this because of the bilateral treaty, Russia the United States could missile capabilities in the A bilateral was no well for a a second of increasing complexity to multilateral nuclear In the of ballistic missile steps taken by the United States to itself against small numbers of North ICBMs or ICBMs are by and Russia as the for a more and to their own strategic nuclear the has them for this taken in by will about its own nuclear at an of nuclear one with the United States and Russia, the other with and At a as stability increasingly a multilateral and is that bilateral arms a for strategic is less and less for the world in which we is multilateral arms control likely to the arms control is but seems in any arms control seems but so far remains multilateral arms control is and arms control is but is as successful will on the United States, Russia, and some of If the in this volume by and and make one that will not be the of Russia, China, and the United States, the each a of concerns at with those of at least one of the other For to pursue an approach to nuclear deterrence that the risk of nuclear war remains for the United States, but the context in which the United States must this is Russia, is no a potential in seeking to reduce nuclear but a adversary to create a nuclear posture its The risk to be is first and that deterrence will and Russia, in the in nuclear forces are to the threat by the United its in a the United States on its by nuclear weapons, to threaten and It seeks nuclear superiority and on new technologies and weapons systems intended to the Russian nuclear deterrent and make nuclear weapons more only have and Russian views on what strategic stability making the nuclear arms control a but the way each side both the threat that it in the other weapons and and to them seems likely to the chance of inadvertent escalation across the nuclear In the the between the of the and Russian nuclear and those of all other countries means that the of arms control to In other multilateral arms control is, as not currently an the United States to as a threat and its nuclear forces as a of of the of the nuclear and the it to the all of mutual and potential escalation is the in the of any arms control a of new technologies that overall will make nuclear forces and their and control appear more The most immediate of these is In his the in which weapons from weapons and, in particular, those of that seem that credible approaches to this threat are to the in his a range of new and a to through a on strategic stability. The of his is to ensure that any of new technologies the variety of in which effects may so that possible steps can at least be are we to work within this world to the of escalation to the use of nuclear of our of a but and in their take this as their There is that the United States and Russia take of New that the to the by five its that the and in New START benefit the United States more than Russia because the United States is the more open of the much of the information between the could be by national this would the of these away from other And some of the information provided by New be in any other with other in this that a is is clear about further arms control of any between Russia and the United States seem taken the that further must missile and conventional But it is that will to a and the United States is to negotiate limiting missile one might the of the current to of nearly any and arms control in the end of New bilateral arms control between the United States and Russia in the of to an that it is to what the consequences of this of information and will and to what steps may be taken to for at least some of what will be this an of and on that could be agreed as than agreements. would of be than with New but perhaps some limited verification could be in This would the even if the are more more by incoming and less well the Russian concerns that it is how these may But at the they be the of arms control among the for all nuclear-armed states to a of nuclear and in take the of and to an arms race and reduce nuclear And means to which not only strategic stability and the immediate goal of nuclear war but the ultimate goal of disarmament is, a that the United States it the as of the states, are of the the of the United States to this has greatly from to and in the current state of this goal may seem In the a of that could be pursued some by all nuclear-armed states, some by the United States, Russia, and China, and some by the United One is to ensure that would be the United States, France, and the United as the by and for the of the on the of and the of deterrence to work to find to prevent the worst from coming to of this volume bring a of views to the of strategic stability in this new there is not on several we certain that were made by or a world has with nuclear weapons for the number of states with nuclear weapons has the weapons being used for many have not been detonated in war since the end of World War II. But the new we have is more both and and seems likely to be less by treaty, and therefore less and less than any time in the remains possible that New START can be and to as one for bilateral stability between the United States and In this there would remain many and the United States, Russia, and would need to in to and Absent New the would prove much This volume has to what this coming world may and, to that may a to the worst in these possible

Adversary · Aeronautics · Ballistic missile · Computer security · Explosive material · Homeland security · Marine engineering · Missile · Nuclear physics · Nuclear weapon · Physics · Political science · Submarine · Terrorism · Thermonuclear Fusion · Warhead · Aerospace Engineering · Computer Science · Engineering · History · Law · Nuclear Issues and Defense

• The Rise and Fall of the South African Bomb

  Peter Liberman•International Security•2001

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• On Escalation. Metaphors and Scenarios

  Brian Crane, Brian R Crane et al.•International Journal Canada s…•1965

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• Inadvertent Escalation

  Gregory F Treverton, Barry R Posen•Foreign Affairs•1992

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• A Nuclear World Transformed

  Open Access•Steven E Miller•Daedalus•2020

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• The Revival of Nuclear Competition in an Altered Geopolitical Context

  Open Access•Li Bin, Xibin Li•Daedalus•2020

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• Nuclear Disarmament without the Nuclear-Weapon States

  Harald Müller, Carmen Wunderlich•Daedalus•2020

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• On Adapting Nuclear Deterrence to Reduce Nuclear Risk

  Open Access•Brad Roberts•Daedalus•2020

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• Nuclear Superiority and the Balance of Resolve

  Open Access•Matthew Kroenig•International Organization•2013

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• What Went Wrong with Arms Control

  Thomas C Schelling•Foreign Affairs•1985

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