The Second Nuclear Age is pretty much what it says on the tin; the relevance of nuclear weapons in a post Cold War world. Nuclear weapons, vertical nuclear proliferation, and deterrence strategies undoubtedly had a significant role in the Cold War, and are perhaps one of the lasting images of that era. Since the development and use of the atom bomb by the United States in the Second World War on Hiroshima and Nagasaki, and the Soviet Union’s nuclear test in 1949, nuclear capability became a definite political reality in international relations, with nuclear deterrence, both directed at deterring nuclear and non nuclear actions, becoming a significant part of Cold War foreign policy, and

“every potential conflict was transformed into a potential US-Soviet nuclear war”

– Robert Chandler in Strategic Stability in the Post-Cold War World and the Future of Nuclear Disarmament.

However, the end of this bipolar dimension to international relations has by no means led to an end to the role of nuclear weapons in international relations; it could in fact be argued that nuclear weapons could be more important in the second nuclear age than they were in the first.

Deterrence in the Cold War

The role of deterrence in the Cold War era was a significant part of the role of nuclear weapons in general in this period; from the initial intention of nuclear deterrence, which was to counter the USSR’s vast numerical superiority, and to deter any attempts by the Soviet Union for a massive land invasion of Europe to Mutually Assured Destruction, and the principle of deterrence that it was possible to deter nuclear attacks from one country by, in theory, holding their cities to ransom, making an attack deeply unattractive for either side, especially after the United States’ ability for ‘massive retaliation’ became almost suicidal as the Soviet arsenal increased in size. The very fact that the sheer amounts of nuclear weapons increased on a massive scale, and the fear of nuclear war was always present, but yet it never occurred, shows the massive importance of deterrence during the Cold War.

How does deterrence work in a multipolar world?

However, this model of deterrence is difficult to apply to a post-Cold War world, because it is based around the assumption that two rational superpowers are in control of the high majority of nuclear weapons, and since the break up of the Soviet Union, this has simply not been the case. The number of nuclear weapons may be decreasing, but the powers holding them are increasing in number, and fewer states have the capacity of ‘massive retaliation’; the world has become multipolar in the aftermath of the Cold War, and thus, deterrence is still important, but must be looked at from a multipolar dimension.

Horizontal proliferation –

This, and the importance of new methods of using deterrence, was recognised post-Cold War by all nuclear weapons states, and despite the Non Proliferation Treaty, the uncertainties of the post cold war world have made nuclear deterrence still a viable option for many states; for example, Israel still considers nuclear weapons, and the uncertainty over the size of its arsenal, a real option in maintaining its security in a region which is hostile to its existence, and is still severely concerned about other nations within the region acquiring weapons. For states that consider themselves under a real, and possibly imminent, threat from states which have a sizable advantage in conventional warfare, nuclear deterrence is an acceptable policy. North Korea, which considered a nuclear deterrent a definite option in deterring both American and South Korean aggression, which has allowed them several times to achieve diplomatic and political objectives; for example, the decision by the United States government to diplomatically recognise and talk to the government of North Korea for the first time in 1991.

India and Pakistan are very similar in how they see nuclear weapons as essential for their security, and demonstrate how proliferation has become an issue of regional security, and the conflict over Kashmir is perhaps one of the few where a limited nuclear war appears to be a possibility.

The continuing presence of Nuclear Weapons amongst Permanent Five States-

This does not mean that the original nuclear states; USA, Russia, China, UK and France, do not consider nuclear deterrence a viable option as well, very few of them have actually dismantled their nuclear weapons, and some have even renewed their nuclear capacity. Britain renewed its Trident weapons system, justifying it by claiming that,

“It is not possible accurately to predict the global security environment over the next 20 to 50 years… we cannot rule out the risk either that a major direct nuclear threat to the UK’s vital interests will re-emerge or that new states will emerge that possess a more limited nuclear capability, but one that could pose a grave threat to our vital interests…Conventional capabilities cannot have the same deterrent effect. We therefore see an enduring role for the UK’s nuclear forces… for deterring blackmail and acts of aggression against our vital interests by nuclear-armed opponents.” Ministry of Defence and Foreign and Commonwealth Office, 2005

So, there was a definite sense amongst current nuclear power states that deterrence would remain important as long as other states looked to proliferate nuclear weapons, or there was at least a chance of weapons being proliferated, which as long as nuclear technology exists, there will be a chance of.

Is it really that important any more?

Indeed, after the end of the Cold War, there was also a sense that nuclear deterrence would not have such a huge role, and instead, advanced conventional weapons would play a larger role, especially considering that the feasibility of nuclear deterrence is reduced by the new actors in the post war world; non state actors are very difficult to deter with nuclear weapons, and smaller states with nuclear weapons are still perhaps better deterred by conventional methods than nuclear weapons.

However, both established nuclear states and nuclear capable states consider nuclear weapons important to their security, either to deter aggression from states which have a massive advantage in conventional warfare, or in an attempt to deter further proliferation of nuclear weapons and their use, so deterrence is still a viable political tool in the post cold war era, even if it is a different approach to deterrence than during the Cold War.

Umbrellas and virtual deterrence

During the Cold War, after China acquired nuclear capacity in 1964, there were very few states openly proliferating nuclear weapons until the end of the cold war. Proliferation was mainly vertical, and mainly focused around arms races between the Soviet Union and United States, rather than the acquisition of weapons by new states. Most states considered themselves protected either under the United States’ or Soviet Union’s nuclear umbrella, and saw very little need to develop their own nuclear weapons, which to some extent still stands in the post-Cold War world, with countries like Japan, Germany and South Korea all still relying on American nuclear protection.

However, even some of these states, especially Japan and South Korea have not entirely abandoned the idea, and Japan perhaps relies on its virtual capacity to build a nuclear weapon for security, with large stockpiles of plutonium, and a strong nuclear power industry, rather than American promises of protection, and with North Korean nuclear ambitions, it doesn’t consider nuclear weapons a political impossibility, unlike it did during the Cold War. South Korea, similarly, does not have nuclear weapons, but doesn’t consider itself sufficiently protected by the United States not to have its own ballistic missiles and chemical weapons program, albeit one which is soon to be destroyed.

Rationality of actors

An increase in the amount of states with nuclear capability in turn leads to more uncertainties about when and how they will be used, as Cold War strategies relied on understanding the reasoning of only two, relatively rational, powers; the United States and Soviet Union, but since the end of the cold war, it is increasingly difficult to predict the actions of nuclear actors, as there are more of them, and several of these have a different sense of rationality to the US and USSR had during the Cold War. None of these states have the capability to use Mutually Assured Destruction, apart from America and Russia, and thus increases the chance of a limited nuclear war, as several actors have different senses of rationality, more nuclear actors leads to more uncertainty, and actors, in theory, have less to lose by using a nuclear weapon than they did during the Cold War period.

However, perhaps the most important aspect of post Cold War horizontal proliferation is that ‘rogue states’ now consider nuclear weapons a viable way of deterring US adventurism. Many states, such as North Korea, see nuclear weapons as a legitimate way of countering the massive conventional superiority of the United States, and often use the language and motives of Western nuclear weapons states to justify their acquisition of such weapons, claiming that it would deter American or South Korean attacks, or using it as a political weapon during negotiations. They may have attempted to acquire nuclear capacity during the Cold War, but even after it, nuclear weapons are still seen as a definite realistic prospect for states like North Korea and possibly Iran.

This has made nuclear weapons even more relevant in the post Cold War world, as these states certainly have a different, and more ambiguous rationality to the Soviet Union and United States, as they all have more regional concerns, and are more likely to have one or two nuclear weapons than a whole arsenal, which in turn makes the established nuclear powers’ nuclear strategy more ambiguous, as there would be some uncertainty as to how deterrence would work against states with a different sense of rationality. Rationality is also a serious concern in the post Cold War era, as there is now, for the first time, a possibility that terrorists could get their hands on nuclear material, with the collapse of the Soviet Union and consequent military surplus, and create a dirty bomb, if not a full nuclear missile. The possibility of terrorists acquiring nuclear weapons gives them a new role in international politics, as terrorists, especially religious fundamentalists, have an entirely different set of rationalities and fears to state actors, meaning their actions would be much more unpredictable and dangerous than those of a state. It is also significantly more difficult to act against a terrorist organisation or dissuade them from using a nuclear weapon than a state, and this adds even more uncertainty to the post Cold War era.

However, in some respects, Third World nuclear states could prove much easier to dissuade from developing or using nuclear weapons than other nuclear actors, for example, North Korea was persuaded to have IAEA inspections several times in return for food, oil and other aid, as well as being persuaded to sign a Nuclear-Free Korean Peninsula Agreement with South Korea in return for a stepping down of American military activity in the South. This perhaps shows the role of non-nuclear and diplomatic efforts in dealing with Third World nuclear states, meaning nuclear weapons are not as relevant as it appears. However, many of these states have ignored treaties and agreements they have signed, or withdrawn from the Non Proliferation Treaty, or hindered IAEA inspectors, so it cannot be said such measures have been particularly effective, as to both the Third World states and the other nuclear states dealing with them, nuclear weapons are still vitally important to security.

How important are nuclear weapons in the Second Nuclear Age?

The role of nuclear weapons has altered significantly in the post Cold War world, as they became no longer the preserve of a bipolar world, but an increasingly multipolar political and military weapon, as more states acquired them horizontally and there was increasing uncertainty about who had nuclear capacity and how actors would react. The end of a bipolar world did not necessarily mean the end of nuclear weapons, as even though they are not as symbolic of the post Cold War era as they had been of the Cold War, they are still a vitally important part of security for many states, both established nuclear weapons states and states such as Israel, North Korea, India and Pakistan, and as long as states consider nuclear weapons vital to their security or geopolitical power, they will continue to have a large role, if less direct, in international politics.


Barnabie, F. and Burnie, S. (2005) ‘The Unthinkable: A Nuclear Armed Japan’ Asia Times (Hong Kong) (online) ( 9th of September (accessed 18/03/08)

Becker, J. (2005) Rogue Regime – Kim Jong Il and the Looming Threat of North Korea Oxford: Oxford University Press

Best, M.L et al, (1995) Strategic Stability in the Post-Cold War World and the Future of Nuclear Disarmament. London: Kluwer Academic Publishers.

Butfoy, A. (2008) ‘Nuclear Strategy’ in Contemporary Security and Strategy, edited by Snyder, C, Basingstoke: Palgrave Macmillian

Ministry of Defence and Foreign and Commonwealth Office (2006) The Future of the United Kingdom’s Nuclear Deterrent (online) ( (accessed on 18/03/08)

Nuclear Threat Initiative (2007) Country Overviews: South Korea, (online) ( (accessed 18/03/08)

Walton, C and Grey, C, ‘The Second Nuclear Age: Nuclear Weapons in the Twenty-First Century’ in Strategy in the Contemporary World, edited by Baylis, J. et al, Oxford: Oxford University Press.

Lectures of Professor Colin McInnes, Aberystwyth University

Log in or register to write something here or to contact authors.