Nuclear Weapons and International Relations

This feature is part of the online resources to accompany the textbook Foundations of International Relations.

After the first uses of an atomic bomb by the United States on Japan in August 1945, reports and pictures of the devastation caused by the two bombs that the United States dropped on Nagasaki and Hiroshima confirmed that the nature of warfare had changed forever. As one reporter described the scene: ‘There is no way of comparing the Atom Bomb damage with anything we’ve ever seen before. Whereas bombs leave gutted buildings and framework standing, the Atom bomb leaves nothing’ (Hoffman 1945). The quest to regulate nuclear weapons offers a glimpse of interactions between states that were sworn enemies and had little in common due to incompatible economic and political systems. Yet, through diplomacy and the influence of the United Nations, they were able to avoid war and find ways to achieve progress in the most critical of areas.

Although the United States was the first state to successfully detonate a nuclear weapon, others soon followed – the Soviet Union (1949), the United Kingdom (1952), France (1960) and China (1964). As the number of nations possessing nuclear weapons increased from one to five, there were fears that these weapons would proliferate (spread rapidly). This was not only a numbers issue. As the weapons developed, they became many orders of magnitude more destructive. By the early 1960s, nuclear weapons had been built that could cause devastation across over one hundred square kilometres. Recognising the danger, the United Nations attempted in vain to outlaw nuclear weapons in the late 1940s. Following that failure, a series of less absolute goals were advanced, most notably to regulate the testing of nuclear weapons. Weapons that were being developed required test detonations – each releasing large amounts of radiation into the atmosphere, endangering ecosystems and human health. By the late 1950s, diplomacy under a United Nations framework had managed to establish a moratorium (suspension) on nuclear testing by the United States and the Soviet Union. However, by 1961 a climate of mistrust and heightened Cold War tensions between the two nations caused testing to resume.

One year later, in 1962, the world came to the brink of nuclear war during the Cuban Missile Crisis when the Soviet Union placed nuclear warheads in Cuba, a communist island nation-state approximately 150 kilometres off the southern coast of the United States. Cuban leader Fidel Castro had requested the weapons to deter the United States from meddling in Cuban politics following a failed US-sponsored invasion by anti-Castro forces in 1961. As Soviet premier Nikita Khrushchev (1962) put it, ‘the two most powerful nations had been squared off against each other, each with its finger on the button’. After pushing each other to the brink of a nuclear war, US President John F. Kennedy and Khrushchev found that via diplomacy, they could agree to a compromise that satisfied the basic security needs of the other. Over a series of negotiations, Soviet missiles were removed from Cuba in return for the United States agreeing to remove missiles they had deployed in Turkey and Italy. As the two sides could not fully trust each other due to their rivalry, the diplomacy was based (and succeeded) on the principle of verification by the United Nations, which independently checked for compliance. Building further on the momentum, in July 1963 the Partial Test Ban Treaty was agreed, confining nuclear testing to underground sites only. It was not a perfect solution, but it was progress. And, in this case it was driven by the leaders of two superpowers who wanted to de-escalate a tense state of affairs.

Although early moves to regulate nuclear weapons were a mixed affair, the faith that Kennedy and Khrushchev put in building diplomacy facilitated further progress in finding areas of agreement. In the years that followed the Cuban Missile Crisis, Cold War diplomacy entered a high-water-mark phase in what became known as a period of ‘détente’ between the superpowers as they sought to engage diplomatically with each other on a variety of issues, including a major arms limitation treaty. In that climate, progress was made on restricting nuclear proliferation.

The Treaty on the Non-Proliferation of Nuclear Weapons (1970) – often known as the Non-Proliferation Treaty – sought to channel nuclear technology into civilian uses and to recognise the destabilising effect of further nuclear proliferation. It was a triumph of diplomacy. The genius of the treaty was that it was aware of the realities of the international politics of the time. It was not a disarmament treaty as great powers would simply not give up their nuclear weapons, fearful their security would be diminished. So, instead of pursuing an impossible goal of eliminating nuclear weapons, the Treaty sought to freeze the number of nations that had nuclear weapons at the five states that already possessed them. Simultaneously, those five nations were encouraged to share non-military nuclear technology with other states – such as nuclear energy and nuclear medicine – so that others would not feel tempted to pursue nuclear weapons. In short, those who had nuclear weapons could keep them. Those who did not have them would be allowed to benefit from the non-military research and innovation of the existing nuclear powers.

Due to the well-considered design of the treaty and its enforcement, it has been highly successful. Following the end of the Cold War, the Non-Proliferation Treaty was permanently extended in 1995. Granted, it has not kept the number of nuclear nations to five, but there are still fewer than ten – which is far from the twenty or more projected before the treaty entered into force. States with nascent nuclear weapons programmes, such as Brazil and South Africa, gave them up due to international pressure. Today, only a small number of states are outside its bounds. India, Pakistan and Israel never joined as they (controversially in each case) had nuclear ambitions that they were not prepared to give up due to national security priorities. Underlining the weight of the Non-Proliferation Treaty, in 2003, when North Korea decided to rekindle earlier plans to develop nuclear weapons, they withdrew from the treaty rather than violate it. To date, North Korea remains the only state to withdraw from the Non-Proliferation Treaty.

The non-proliferation regime is not perfect, of course – a situation best underlined today by North Korea. It is also a system with an inherent bias, since a number of states are allowed to have nuclear weapons simply because they were among the first to develop them, and this continues to be the case regardless of their behaviour. Yet, while humankind has developed the ultimate weapon in the nuclear bomb, diplomacy has managed to prevail in moderating its spread. When a state is rumoured to be developing a nuclear bomb, as in the case of North Korea, the reaction of the international community is always one of common alarm. We call ideas that have become commonplace ‘norms’ and non-proliferation has become one of the central norms within our global system.

It may seem strange but, despite their offensive power, nuclear weapons are primarily held as defensive tools – unlikely to be ever used. This is due to a concept central to IR known as ‘deterrence’. By holding a weapon that can (if used) endanger the very existence of an opponent by potentially wiping them out, such an opponent is unlikely to attack you as the risk is too high. Especially if your nuclear weapons can (at least partially) survive that attack and allow you to retaliate. This is why states frequently move their nuclear weapons around, place them in submarines or aircraft, and even sometimes install them beyond their borders by agreement with an allied host state. In an environment as insecure as the Cold War, gaining a nuclear arsenal was a way to achieve deterrence from being attacked and thereby a measure of security that was not otherwise attainable. And tens of thousands of nuclear weapons were built and stockpiled by states during the Cold War. Underlining the logic of deterrence, nuclear weapons were never again used in anger after their initial use by the United States in 1945.

Text adapted from McGlinchey, Stephen. 2022. Foundations of International Relations. London: Bloomsbury.

Below is a collection of multimedia resources that help unpack, and explain the importance of nuclear weapons and non-proliferation.

Footage / Accounts of the Atomic Bombs dropped on Japan, 1945

A Time-Lapse Map of Every Nuclear Explosion Since 1945

Mutually Assured Destruction

Nuclear Weapons – Overviews and Analysis

Textual Content and Websites

Arms control Fact Sheets – The Arms Control Association maintains over 100 regularly updated factsheets on a range of regional and topical arms control issues.

World101 module: The Nuclear Nonproliferation Treaty

‘The NPT at Fifty: Successes and Failures‘, journal article by Nobuyasu Abe.

At The Brink – a podcast discussing the impact of nuclear weapons.

Nukemap – An interactive graphic to explore the impact different nuclear warheads would have on your own city or region.

Nuclear Files – Website examining political, legal and ethical challenges of nuclear weapons.

Further Reading on E-International Relations

Please Consider Donating

Before you download your free e-book, please consider donating to support open access publishing.

E-IR is an independent non-profit publisher run by an all volunteer team. Your donations allow us to invest in new open access titles and pay our bandwidth bills to ensure we keep our existing titles free to view. Any amount, in any currency, is appreciated. Many thanks!

Donations are voluntary and not required to download the e-book - your link to download is below.


Get our weekly email