Nuclear peace in the 21st century: is the deterrence theory still valid?

di Juline Lefevre Lancelot - 1 Aprile 2021

  from Paris, France


“It is the presence of nuclear weapons that threatens our existence”, declared Paul Nitze, President Ronald Reagan’s Special Advisor on Arms Control, eight years after the Cold War, meaning that he changed his opinion on the use of nuclear weapons to maintain peace in the world. 

This change is significant, as the experts on international relations knew this fact for decades, and tried to stress awareness on the danger of the detention of nuclear weapons after the fall of the bipolar international system. It is quite paradoxical that the world was in fact more alert to a nuclear crisis during the Cold War than today when nuclear risks are actually growing day by day for 30 years. 

In 2021, nearly 76 years after the horrific use of nuclear bombs by the USA on Hiroshima and Nagasaki, the nuclear war seems to have become an abstract idea, when multiple states threatened each other with nuclear weapon use. While nuclear-armed states parade their weapons to intimidate their opponents, just like North Korea and the United States who threaten each other with annihilation (Gilinski, 2020),  is it still even relevant nowadays to talk about nuclear peace?  

It is generally ignored that there have been a lot of close calls (Moniz, 2020). As we are losing the last generation that remembers Hiroshima & Nagasaki nuclear bombings, we must face the truth: the risk of a nuclear weapon’s being used is almost higher today than during the Cuban Missile Crisis of 1962.


The poisonous gift

On December 2, 1942, Enrico Fermi and his team succeeded in making the first nuclear chain reaction, which allowed the creation of not only atomic bombs but also nuclear medicine and clean energy. This huge breakthrough led to the death of an estimated number from 150,000 to 280,000 Japanese noncombatants (Campaign for Nuclear Disarmament, 2017). This bombing is generally described as the event that was responsible for the end of WW2.

Still, the end of the Second World War had an enormous price, regarding humanity. As  the Argentine daily Critica of August 8, 1945, can testify, by sharing a Japanese reaction broadcast on Radio-Tokyo: “The use of the atomic bomb against Hiroshima is yet another example of the evil nature of the enemy, which has no scruples in massacring civilians ” (Critica’s first page, 1945). 

These two atomic bombs were the only ones used, and it may be because of the attached atrocity of this action or because of the exceptional diligence and diplomacy that rule in international relations since the end of the Second World War. But it could also because of luck (Moniz, 2020)

Meanwhile, aside from nuclear peace, the number of countries possessing nuclear weapons, nuclear materials, and technology has increased. About 13,410 nuclear weapons exist today, and most of them are more powerful, some are even three times more devastating than those which erased the two Japanese cities (Future of Life Institute, 2019). 

Yet nuclear-armed states plan to upgrade their nuclear arsenals, even though experts consider it as increasing the risk of nuclear war (Future of Life Institute, 2019).

The daunt so-called “known consequences” of the use of nuclear power …  

Everyone has heard about the impact of an atomic bomb, based on the experience of Japan. But most of us don’t really know what to expect if ever a nuclear weapon was to be used. Even the International Committee of the Red Cross (ICRC) and the International Federation of Red Cross and Red Crescent Societies (IFRC), who conduct revealing scientific studies, are only sure about one thing: the use and even the testing of nuclear weapons harm human health and the environment in the long-time period. Otherwise, there are some aspects of these impacts that are not fully understood (ICRC, 2020).

Scientists keep discovering new fatal effects of nuclear weapons. Thus, the list of possible damages to human health remains blurred (Future of Life Institute, 2019).


… are not as frightening as the uncertainty of other uncertain outcomes.

The discovery of the “nuclear winter” in the 1980s, which consist of massive amounts of smoke spreading around Earth, blocking out sunlight (Future of Life Institute, 2019), made the researchers realize that the use of nuclear weapons would not result in a “Mutual Assured Destruction” (MAD) but in a “Self-Assured Destruction” (SAD) (Robock and Toon, 2021). Indeed, if a nuclear attack was launched, the States that started would be destroyed as well, because of the nuclear winter. Moreover, we must take into account the fact that research on the impact of nuclear winter was run in the 1980s, and that they were probably underestimated. Today, even a nuclear war against small countries could produce a nuclear winter. For instance, India and Pakistan each have 50 Hiroshima-size atom bombs (Robock and Toon, 2021).

A wider risk of nuclear war in a multipolar world

A disturbing number of close calls occurred, in which miscalculation was one of the main triggers (Lewis, Pelopidas, and Williams, 2014). In 2014, the International Conference on the Humanitarian Impact of Nuclear Weapons demonstrated that the risk of nuclear weapon use is most likely to emerge from the following situations. Firstly, the vulnerability can come from human error and cyberattacks on command-and-control networks. Secondly, it is the maintenance of nuclear arsenals on high levels of alert, that contains thousands of nuclear weapons (ICRC, 2020). The last thing to take into account is the dangers of non-state actors accessing nuclear weapons. 

Thus, the risks are inherent to the structure of a multipolar world. Indeed, contrary to the situation in a bipolar world, all of the states and other international actors – which include terrorist organizations – have the possibility of becoming the hegemon, because there is no Superior authority that has power over international relations. 

Moreover, in a multipolar system, it is much more complicated to predict the actions of the states, where every sovereign state is formally equal in this system. Following Mearsheimer’s neorealist theory, these states act in accordance with their own interests in order not to be subordinated by another state. Therefore, states have a “driving force of survival”, which is influencing their behavior on the international stage. This explains why each state wants to develop its defense capacities, including nuclear weapons. Moreover, as there is no certainty of the other states’ intentions, the lack of trust leads them to always be on their guard. In addition, Mearsheimer explains that each state wants to maximize its power, aiming for regional hegemony (Mearsheimer, 2014). 

“There is a rising challenge presented by the possibility for many-sided nuclear crises involving more than two actors given the possible temptations for by-stander states to join a war at a late stage to gain some unique advantage”, confirmed the Defense Threat Reduction Agency in 2000 (Roberts, 2000)

Thus, the probability of nuclear war is increased by geopolitical developments which generate the possibility of conflicts between nuclear-armed states (ICRC, 2020). On top of that, the weakening of the nuclear arms control framework makes it more difficult to foresee the future of nuclear peace. 


The 21st century: it is time to reconsider the Non-Proliferation Treaty strategy    

“If we believe that the spread of nuclear weapons is inevitable, then in some way we are admitting to ourselves that the use of nuclear weapons is inevitable.”, affirmed Barack Obama in 2009, referring to the urge of reinforcing the non-proliferation strategy. 

The NPT (Non-Proliferation Treaty) was signed in 1968 by 46 states. Today it has 191 signatures and remains the foundation for the spread of nuclear weapons prevention. In short, the signatories non-nuclear states agree never to acquire nuclear weapons, in exchange for the nuclear states to share the benefits of peaceful nuclear technology, and nuclear states agreed to pursue nuclear disarmament, until the removal of their nuclear arsenals (Thomas, 2004). Yet, today disarmament efforts have drastically stalled and the restraints of nuclear weapon use are also weakening (Moniz, 2020)

On the one hand, signs that the respect for the NPT is diminishing are clear: in 2018, the Saudi crown prince’s declared to the US that he would get nuclear weapons if Iran did (Gilinski, 2020). In the same way, in 2019, Turkish President Erdogan claimed that it was unacceptable that Turkey was not permitted to have nuclear weapons, suggesting his opinion about the NPT.  On the other hand, we are witnessing a blur in the threshold for using nuclear weapons, with technology improvements such as tactical weapons (Gilinski, 2020). For example, Pakistan created tactical nuclear weapons that are easier to carry out, in order to be considered as a bigger threat. 

In the present circumstances, when the NPT is analyzed with the “game theory”, we can see why it is not as efficient as expected. Due to the fact that the treaty lets countries gain entry-level nuclear technology for civilian use, nothing prevent them from building more puissant reactor and then making bombs… Moreover, the “Mutually Assured Destruction” is not valid anymore, and the multipolar world has become more complex. This leads to a rise in the possibility of decisions, responses, and miscalculations… (Kluth, 2020)

On July 7, 2017, the UN General Assembly passed the first binding treaty for a gradual elimination of nuclear weapons, with “the Treaty on Prohibition of Nuclear Weapons”. However, it does not apply to nuclear-weapon states since none has signed the Treaty. As a consequence, nothing can legally prevent nuclear proliferation, even though risks are extending.


The deterrence theory is not reliable anymore

In these times, it is easy not to think about nuclear war risks, because they do not occur in our everyday life. On top of that, the deterrence theory is so fixed in conventional thinking that people do not seem to see the political and social changes that threaten nuclear peace. Some experts are still convinced that nuclear deterrence will keep working since it worked during the Cold War (Gilinski, 2020). However, this deterrence theory remains a simple theory and was never proven: other factors may have influenced national leaders not to use nuclear weapons during the Cold War. 

Moreover, deterrence is based on the idea of retaliation, but we cannot control the mind of our opponents. Thus, it is far from being a reliable science. Miscalculation is not only a risk belonging to the multipolar system, but it also was during bipolar one. “Human beings are especially prone to do foolish things when under pressure” (Gilinski, 2020). A lot of politicians and historians suggested that there is a part of luck if no nuclear weapon was used.

Another disqualifying sign is the declining credit given to “no-first-use” pledges (Gilinski, 2020), as Russia has withdrawn its earlier pledge, and China appears to reconsider it. As for the United States, they never signed on. 

Consequently, the original nuclear deterrence theory does not work anymore, since the ‘MAD theory’ was proven to be incorrect, and needs to be reconsidered (Kissinger, Nunn, Schultz, Perry, 2011). As Shultz, Perry, Kissinger, and Nunn ask, “does the world want to continue to bet its survival on a continued good fortune with a growing number of nuclear nations and adversaries globally?”. There is an urgent need for a safer and more comprehensive form of deterrence.


References (A-K)

Campaign for Nuclear Disarmament. 2017. Hiroshima and Nagasaki. [online] Available at: <>[Accessed 15 March 2021].

Critica, 1945, Ha Desaparecido Toda Vida Humana, Animal Y Vegetal En La Zona De Hiroshima, Argentina.

Future of Life Institute. 2019. The risk of nuclear weapons. [online] Available at: <>[Accessed 15 March 2021].

Gilinski, V., 2020. Nuclear risks are growing, and there’s only one real solution. [online] Bulletin of the atomic scientists. Available at: <> [Accessed 15 March 2021].

Graham, Jr., Thomas (November 2004). “Avoiding the Tipping Point”. Arms Control Association.

ICRC, 2020. Humanitarian impacts and risks of use of nuclear weapons. [online] ICRC. Available at: <> [Accessed 13 March 2021].

Kissinger, Nunn, Schultz and Perry, 2011. Deterrence in the Age of Nuclear Proliferation. [online] WSJ Opinion. Available at: <> [Accessed 18 March 2021].

Kluth, A., 2020. The risk of nuclear war is growing. [online] Thejapantimes. Available at: <> [Accessed 11 March 2021].


References (L-Z)

Lewis, P., Pelopidas, B. and Williams, H., 2014. Too Close for Comfort: Cases of Near Nuclear Use and Options for Policy. [online] Chatham House. Available at: <> [Accessed 17 March 2021].

Mearsheimer, John J. (7 April 2014). The Tragedy of Great Power Politics (Updated Edition) (ISBN : 9780393349276). 

Moniz, E., 2020. The risk of a nuclear attack is back at historic levels, 75 years after Hiroshima. [online] THINK. Available at: <> [Accessed 14 March 2021].

Roberts, B., 2000. Nuclear Multipolarity and Stability. [online] Institute for defense analyses. Available at: <> [Accessed 14 March 2021].

Robock, A. and Toon, O., 2021. It is 5 minutes to midnight. [online] Self-assured destruction: The climate impacts of nuclear war. Available at: <> [Accessed 19 March 2021].

Sivaraman, B., 2020. Nuclear modernisation: The emerging threat to global peace. [online] Available at: <> [Accessed 16 March 2021].



Autore dell’articolo*: Juline Lefevre-Lancelot, studentessa di Political Science, Law, Economics and Interntional Relations at Sciences Po Lille. Come sempre pubblichiamo i nostri lavori per stimolare altre riflessioni, che possano portare ad integrazioni e approfondimenti. 


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