The prospect of the use of nuclear weapons in Ukraine has focused attention on the potential military, humanitarian and environmental impact, as well as raising the possibility of escalation into a much larger nuclear conflagration. It has been argued, for instance, that Russian use of ‘battlefield’ nuclear weapons would not lead to a military victory for Moscow. Ukraine would continue fighting and Russia would remain in a quagmire. Other scenarios, such as nuclear use on Ukrainian population centres, or the targeting of nuclear power plants, are much grimmer. The default reaction of nuclear policy analysts has been to examine these different scenarios in the narrow context of the war. Little attention, if any, however, has been given to thinking about the context of global nuclear policymaking in the aftermath of nuclear use. Important questions remain unaddressed. What would the international reaction consist of? How would nuclear policies around the world be affected? Would Russian nuclear use in Ukraine lead to the collapse of existing nuclear arms control and non-proliferation agreements? Would it result in a massive spur to nuclear disarmament? Or would its impact be negligible?

The problem with avoiding serious contemplation of the post-nuclear use context and the preparation of policy options is that if nuclear use happens it may be more difficult to stop further nuclear use or proliferation, in the absence of a meaningful policy intervention. If the unthinkable occurs and the post-1945 nuclear taboo is broken, would it not be worse if the taboo is not immediately re-established? Could it, in fact, be re-established, or once broken is it broken forever? Whatever else nuclear use entails, it will constitute a political shock. Despite this, its broader policy impact may be more subdued than otherwise appreciated. Indeed, the effect of limited nuclear use on the international system generally, and on the nuclear field specifically, can vary significantly depending on the scenario.

Apart from technical calculations about nuclear effects, many of our ideas about a nuclear aftermath come from films and fiction. The most disturbing images are those that appear in such films as The Day After (1983) and Threads (1984). In both films a conventional war in Europe quickly escalates from local battlefield nuclear use to large-scale nuclear war. When presented with the apocalyptic images portrayed in these films there seems little point in considering the aftermath from a policy perspective. Why bother to think about nuclear disarmament after such a cataclysm when all that matters is survival? Surely the important thing is to make sure it never happens. This reaction is hard to fault. In the scenarios illustrated by those films there isn’t much of an international system left. At best, only a handful of shocked survivors suffering from radiation sickness remain.

By contrast, there are also many fictional works that present a very different image. For example, at the end of the novel Fail Safe (1962), with Moscow and New York about to be destroyed by nuclear bombs, the nuclear strategist Professor Groeteschele looks to the aftermath of the destruction of both cities, and contemplates his own future career prospects in a world where the Americans and Soviets reduce their nuclear arsenals to a low level. Implicit in Groeteschele’s reasoning is the idea that such an accident involving nuclear weapons would create sufficient political momentum for the two superpowers to significantly reduce, if not potentially eliminate, their nuclear arsenals. The arguments of defence intellectuals in favour of retaining large nuclear arsenals would be drowned out by the public outrage.

General Sir John Hackett’s The Untold Story (1982), a sequel to the original The Third World War (1978), in which Birmingham and Minsk are destroyed by nuclear weapons, presents a somewhat different perspective. Hackett’s version of nuclear use occurs as part of an escalation arising from a conventional NATO-Soviet war in Europe. After losing the war, the Soviet Union breaks apart, is occupied by an international force, and surrenders its nuclear arsenal to the Americans. At this point, although the United States and China, the two superpowers emerging from the war, retain their nuclear weapons, Hackett refers to ‘a small window of opportunity’, whereby every other country with nuclear weapons or nuclear programmes would give them up. Britain and France agree to a ten-year phase out of their nuclear arsenals, provided other countries do the same. Any country that refuses to give up their nuclear programmes is told that their facilities will be destroyed.

H.G. Wells’s A World Set Free, which came out just before the First World War, was the first book not only to describe a devastating war waged with atomic weapons, but also the first to describe a post-war world government that comes to power and immediately implements atomic disarmament. Harold Nicolson’s Public Faces (1932) describes a nuclear accident caused by the British that destroys a large part of the American east coast. After this accident, the British blackmail the rest of the world into disarmament. In exchange for abandoning all forms of aerial and submarine warfare, the British agree to destroy their stocks of atomic weapons after a period of six months.

Each of these fictional works describes some type of nuclear shock followed by some level of disarmament. The international system changes, in some ways more substantially than in others, but life goes on. Only in Wells’s novel does the war last for an extended duration, with most societies destroyed in the process. The other three are notable in that the shock following limited nuclear use creates a window for policy change.

Such a perspective about the prospects for change may be overly optimistic. Declassified scenarios developed by the CIA during the 1950s through to the early 1970s, that attempted to gauge international reactions to US and Soviet limited nuclear use in Asia, tended to downplay or ignore the prospect of any significant political change. The immediate consequence of limited nuclear use tends to be a propaganda fiasco and political sanctioning of the nuclear user, rather than the risk of further nuclear escalation or the prospect of nuclear disarmament.

During the 1958 Quemoy-Matsu crisis, the CIA speculated about reactions to US nuclear use against China in defence of the offshore islands. One memo from September 1958 noted that the reaction from US allies would be ‘highly adverse’, and in most of Asia the American use of nuclear weapons ‘would tend to be looked upon as callous white indifference to the lives of Asians’, albeit the Taiwanese and South Korean governments ‘would be encouraged by the vigour of US actions’. If the nuclear use killed large numbers of Chinese civilians, then the US might be forced to withdraw from its bases in Japan and Okinawa due to public outrage. It was also anticipated that western European governments, fearing the risk of escalation to general nuclear war, would apply pressure to terminate the hostilities.

A March 1966 CIA memorandum, on ‘Use of Nuclear Weapons in the Vietnam War’, stated the prospect of nuclear use would be ‘one of the most important events of modern history’ and there would be a ‘widespread and fundamental revulsion that the US had broken the 20-year taboo on the use of nuclear weapons’. And yet, despite its historical significance, the actual international consequences would be relatively limited. The list included: a souring of US-Japan relations; ‘some accelerated momentum toward nuclear proliferation’ that is simultaneously accompanied by ‘international pressure for disarmament … with scant patience for the technicalities of verification’; ‘a probable resolution of condemnation in the UN’; ‘NATO would be badly shaken’; and a loss of allied support for US policy in Vietnam. It was expected that the Soviet Union would refrain from entering the war or from using nuclear weapons, preferring instead to take advantage of the situation to make political and propaganda gains. Meantime, the war on the ground in Vietnam would continue. The March 1967 JASON advisory group report on ‘Tactical Nuclear Weapons in Southeast Asia’ similarly noted the ‘military advantages of unilateral use are not overwhelming enough to ensure termination of the war’.

Several years later, the CIA speculated about a Soviet invasion of China. In one January 1971 estimate it was observed that Moscow would avoid using nuclear weapons because ‘they might pay a very heavy price … if they were the first to violate the nuclear truce of the past quarter century’. Moreover, the Soviet image around the world would be undermined, the US would be more inclined to use nuclear weapons in Vietnam, and countries such as India, West Germany and Japan might be encouraged to acquire their own nuclear arsenals.

As the CIA scenarios of ‘limited’ nuclear use suggest, several international reactions are conceivable. The most immediate is condemnation. It is assumed that the image of the nuclear user will be tarnished, and that country’s foreign policy and political leadership are likely to receive some amount of backlash, though, depending on the circumstances of the nuclear use, the user’s allies may actually be supportive rather than critical. Importantly, there is no sense there will be any imminent arms control or disarmament breakthroughs, either at a national, regional or global level. As some of these scenarios suggest, limited nuclear use in these conflicts is probably insufficient even to stop the fighting, and may result in further nuclear proliferation. Although these and similar scenarios have been used by political scientists to make the case about the existence of a nuclear taboo (consisting of moral and ethical concerns, an abstract fear of opening Pandora’s Box) and its importance in deterring policymakers from nuclear use in various crises, the assumptions about the consequences underpinning the taboo have not been sufficiently studied from the perspective of their wider impact, or lack thereof. Put another way, the type of nuclear use discussed in these scenarios does not automatically lead to any revolutionary changes in the international system, or in the nuclear status quo.

This raises the question, what is the relationship between nuclear use and nuclear policy change? Before attempting to shed light on this question it is necessary to distinguish between two labels: ‘nuclear war’ and ‘nuclear use in war’. When political statements are made to the effect that a ‘nuclear war cannot be won and must never be fought’, the term ‘nuclear war’ is normally associated with massive nuclear use resulting in millions of civilian casualties, possibly tens or hundreds of millions. These are the images of Armageddon portrayed in The Day After and Threads. But they are not the images one necessarily has when thinking about a handful of ‘battlefield nuclear weapons’ being used against military targets, or some type of nuclear demonstration in a relatively isolated area. To describe the latter scenario, I prefer ‘nuclear use in war’ because nuclear weapons are being used alongside other weapons, or at least in a much more limited way than is otherwise implied by ‘nuclear war’. Notably, the boundaries between ‘nuclear war’ and ‘nuclear use in war’ are far from clear. How should we think of the atomic bombing of Hiroshima and Nagasaki? Because of these two nuclear attacks, should we think of the Second World War as a ‘nuclear war’? If a nuclear power plant is deliberately targeted, does this constitute ‘nuclear use in war’? Moreover, with limited nuclear use the prospect of ‘victory’ should not be written off entirely. It is not inconceivable that political and military objectives in a conflict may be attained by nuclear use. Nevertheless, any such ‘victory’ may very well be a pyrrhic one as it would likely be achieved at the expense of international sanctions, imposed for breaking the nuclear taboo. It is crucial, though, to distinguish here between limited nuclear use to defend oneself or one’s allies against attack versus use by an aggressor for coercive purposes.

While these distinctions may be dismissed as an irrelevant semantic debate, the distorting effects of imprecise terminology for thinking about the prospects of nuclear policy change are quite significant. Consider two inter-related issues. The first is the relative probability of alternative types of policy change. The type of ‘nuclear war’ described in terms of one that ‘cannot be fought’ is one in which policy change is essentially irrelevant. Either the war doesn’t occur and the nuclear taboo holds, in which case the natural evolution of nuclear policy is likely to remain relatively undisturbed, or large-scale nuclear use occurs, destroying the international system and society as we know it, in which case policy change would be dictated by circumstances, rather than by policy arguments, new international agreements, and so forth.

In contrast, nuclear use in war, which is to say breaking the nuclear taboo to some limited degree, can offer multiple points where a positive policy intervention may occur (for example, in the immediate period after the limited nuclear use but before it potentially escalates into larger scale nuclear use, or in the period prior to other wars breaking out in which nuclear use becomes ‘acceptable’).  Apart from the immediate priority of helping the victims, is it not likely, as with the case of other shocking events and disasters, such as 9/11 or the Covid pandemic, that the resulting public fear or outrage would open a policy window in which policy changes at the national, regional or international levels, previously viewed as unthinkable, instantly become thinkable? The contours of such a post-nuclear use policy window are impossible to define, particularly the duration that the window remains open and the uneven political effect of the shock on different governments. Nevertheless, the existence of some type of policy window can probably be assumed. For instance, despite the lack of nuclear use during the Cuban Missile Crisis, such was the shock resulting from the prospect of nuclear escalation that a policy window briefly opened, allowing for US, Soviet and British agreement on the Limited Test Ban Treaty.

As with the post-1945 nuclear debate, policy formulation following future nuclear use is almost certain to be highly contested. Advocates for arms control, disarmament, as well as building more nuclear weapons or maintaining the status quo, will each present their case set against the backdrop of the nuclear use shock. At a minimum, some alteration to the existing arms control and non-proliferation regimes would be inevitable. However, as far as one can tell, within the nuclear policy community today there is a lack of interest, much less any attempt at preparedness, for thinking about how nuclear use might seriously affect longstanding efforts to influence or change policy in one direction or another. The reasons are obvious. Either the utility of contingency planning for a hypothetical situation is deemed insufficient, or perhaps it is considered immoral to do so. After all, how can one even think about taking advantage of a tragedy to advance a policy agenda? Does thinking about it somehow risk making it more acceptable and, therefore, likely? On the other hand, history is rarely kind to those who could have prepared for disasters but chose not to.

In the aftermath of nuclear use, one can easily imagine strong arguments to retain the nuclear status quo. Maintaining one’s nuclear arsenal or building a new nuclear deterrent capability may be viewed as the only way not to be attacked in the future. It is entirely plausible that were Russia to use nuclear weapons in Ukraine, feelings of disgust would be mixed with a desire to seek shelter under a nuclear umbrella. What is the likelihood of states falling back on nuclear deterrence as opposed to quickly pressing forward with a new nuclear arms control agreement, a new Nuclear Weapons Free Zone, or signing up en masse to the Treaty on the Prohibition of Nuclear Weapons? Would the two nuclear powers be any more likely to sign up to and implement a Global Zero Action Plan, or would they remain unwilling to budge from their longstanding opposition? Would the international reaction be any different if the nuclear user was North Korea, Pakistan, Israel, Iran or the US, rather than Russia?

The degree to which policy change is possible will, in the first instance, be linked to the sense of shock, which, in turn, will be determined by the type of nuclear use. Isolated nuclear use that is intended for demonstrative purposes, such as at sea or in space, or is targeted against frontline military forces, will evoke a very different level of outrage than if one or more population centres are targeted. The most pressing question is whether the outcry triggered by nuclear use will be sufficient to motivate meaningful policy change, or might it merely result in short term anger and half-hearted protest, followed by a return to the status quo within a few weeks or months? The answer to this question will relate to the extent different nuclear policy constituencies recognise the immediate aftermath of nuclear use as constituting a ‘policy window’ and are able to move quickly to seize the moment by putting forward credible policy proposals and mobilising mass public support.

Assuming it passes without incident, the ongoing nuclear crisis with Russia will hopefully generate renewed interest in, and new approaches to, dealing with nuclear policy problems. For the moment, the main priority is clear: do everything possible to prevent nuclear use. Analysts and activists have a role to play, albeit that their contribution typically involves restating long-held views and providing an informed perspective in the public policy debate rather than developing novel concepts. Nevertheless, as argued here, there is still much space for conceptual innovation. That the world is now faced with a significant risk of nuclear use is a shocking development in its own right and should, ideally, provoke critical self-reflection within the nuclear policy community. What does it mean to be living in a period of history in which the risks of nuclear use are greater than they have been for a generation?  How should we think differently about those risks, and ways to mitigate or eliminate them? With luck, this crisis will pass without nuclear use. On the other hand, would not the nuclear policy community, and particularly arms control and disarmament advocates, be rightly accused of negligence if they didn’t pay at least some attention to formulating options should nuclear use occur in the current crisis with Russia, or for some future one, perhaps in South Asia, the Korean Peninsula or the Middle East? Surely, if there is one thing worse than nuclear use, it is nuclear use followed by more nuclear use or a nuclear arms race. Even if the former cannot be prevented, perhaps the latter still can.