Ask an Expert about the Bomb

Dr Wilfred Wan, Director of the SIPRI Weapons of Mass Destruction Programme and leader of our working group on international law

– It’s a really good question. Almost universally, policymakers, experts and other actors actually agree about the need for disarmament. They recognize the value of a nuclear weapon free world for peace and security.

The problem is that not everyone thinks that the conditions are right for disarmament. Decision-makers in the nuclear-armed states often refer to the broader security environment, to the behaviours of other states, to justify keeping their nuclear weapons, or growing their stockpiles. And unfortunately, more states now think that nuclear weapons can guarantee their security as well.

But more nuclear weapons will contribute to greater tension, instability and create potential for conflict. With no limits on their numbers, types, or placement, there is a greater risk that they’ll be used, on the battlefield, to deliver a first strike, or even by mistake. Nuclear weapons aren’t the solution, they’re the problem.

So it’s important for all of us to educate ourselves about the risk associated with nuclear weapons, about the catastrophic consequences that would result from their use, and to challenge arguments that assume the value of nuclear weapons. And we can all play a role in convincing officials that the right time, the perfect time, for nuclear disarmament is now.

Thomas Jonter, Visiting professor at the Department of Peace and Conflict Research, leader of the AMC working group "Nuclear Disarmament in a Nordic Perspective"

Many thanks for this interesting and relevant question. I think the best way to answer your question is to first reflect a bit on why some states are acquiring nuclear weapons, while other countries have refrained from doing so. There is no simple and unambiguous answer to that question in the research literature. Indeed, states are often driven to pursue nuclear weapons by security concerns and the belief that such capabilities offer the ultimate guarantee of national survival. While the threat environment and technological ability are significant factors, the decision to develop nuclear arms is complex and varies across countries. Some nations see nuclear weapons as essential for deterrence and bargaining power, particularly when facing regional adversaries or uncertain alliances.

Despite having the capability and sometimes facing security threats, many states choose not to pursue nuclear weapons. This restraint is often rooted in international commitments, such as the Treaty on the Non-Proliferation of Nuclear Weapons (NPT), and the desire to contribute to global stability. In fact, it is now established that at least 143 states have never even had any nuclear weapons-related activities. In addition, a majority of the states that initiated research to potentially acquire nuclear weapons have, in fact, abandoned those plans. For example, Sweden and Switzerland both initiated nuclear research programs during the Cold War, motivated by concerns about their security and the global arms race. Ultimately, these countries decided to abandon their nuclear ambitions, concluding that international efforts toward disarmament and non-proliferation would provide greater security. Their decisions were shaped by diplomatic engagement and a commitment to global norms, illustrating that security can be maintained without nuclear armament.

Some states have nevertheless concluded that nuclear weapons are the ultimate and essentially the only guarantor of security. There are, unfortunately, good reasons to believe that the number of states aspiring for nuclear weapons will grow, given the current uncertain geopolitical situation. The strategies they will use will be based on their access to weapons-grade material and technology. It is also important to understand the relationships between aspiring states and leading nuclear-weapon states such as the United States, Russia, and China. These relationships can influence the path a state chooses to acquire nuclear weapons. For some, a “security guarantee” refers to an explicit or implicit promise of protection from a major nuclear power, which can deter the pursuit of independent nuclear arms. For example, a country allied with the United States may rely on the U.S. nuclear umbrella for its defence instead of developing its own arsenal.

Additionally, some states may use their nuclear programs as a “bargaining chip”—a tool to negotiate assistance, economic aid, or diplomatic concessions from larger powers. For instance, by demonstrating progress in nuclear development, a country might leverage its position to secure favourable terms in international talks or obtain security assurances. These strategies highlight the complex interplay between technological capability, diplomatic relations, and national security objectives in nuclear proliferation. This could involve hosting nuclear weapons or obtaining assurance of inclusion in the nuclear state's defence zone. Other potential proliferators will most likely use one of the alternatives mentioned in the question or a combination of two or more of them. Below are key proliferation strategies mentioned, defined and explained for clarity:

• Bomb on the Shelf: This strategy involves developing nuclear weapons and keeping them ready for deployment, but not publicly acknowledging their existence. The weapons are essentially “on standby,” allowing a country to quickly reveal or use them if necessary.
• Oblique Proliferation: Here, a state neither confirms nor denies its nuclear capability, maintaining ambiguity while signalling to other countries that it may possess nuclear arms. This approach can deter adversaries without provoking international backlash.
• Liminal Proliferation: In this case, a country stays at the threshold of nuclear capability, developing the technology and materials needed but stopping short of weaponisation. The state demonstrates its potential to go nuclear, which can serve as a bargaining tool or deterrent.
• India (1974): India conducted its first nuclear test in 1974, known as the "Smiling Buddha." This event marked the country’s entry into the nuclear club but was characterised as a “peaceful nuclear explosion.” India’s approach fits the “1974 Indian-style nuclear bomb” strategy—public demonstration without formal declaration as a nuclear-armed state. Over time, India became more explicit about its nuclear capabilities, citing regional security needs.
• Robust Nuclear Hedging: This involves maintaining a strong capacity to produce nuclear weapons on short notice, often through advanced research and stockpiling materials. The country does not build weapons but ensures it can do so rapidly if threatened. Personally, I think this option will be the most likely chosen alternative.