Eighty years after the first detonation of the atomic bomb, the world is once again witnessing the growing salience of nuclear weapons. Increasing geopolitical competition among the nuclear-armed “great powers” and the demise of international norms and arms control regimes have placed these weapons at the centre of global strategic discourse.
World leaders’ rhetorical restraint regarding the use of nuclear weapons is eroding by the day. We are seeing significant nuclear modernisation and expansion by the nine nuclear-weapon states. Disruptive technologies—artificial intelligence (AI), cyber capabilities, and developments in outer space and hypersonic weapons—are on the rise.
The world is at the cusp of a new nuclear age that is transforming the way deterrence and warfare are conceived.
Tracing nuclear ages
The first nuclear age began with the United States’ Trinity test in July 1945 and lasted until the collapse of the Soviet Union. Characterised by bipolar superpower competition between Washington and Moscow, it led to the evolution of nuclear deterrence strategies based on mutually assured destruction (MAD) and mechanisms of arms control.
The second nuclear age, a term coined by Paul Bracken, began after the end of the Cold War, with the diffusion of nuclear capabilities beyond the official five nuclear-weapon states and the emergence of “regional” deterrence relationships. In the Indian subcontinent, India and Pakistan came to possess nuclear weapons. In the Middle East, Iran, Iraq, and Libya were involved in clandestine nuclear activities. And in the Korean peninsula, North Korea left the Non-Proliferation Treaty to test nuclear weapons. During this phase, concerns shifted from ideological competition between superpowers to the issues of proliferation, stability, regional balance, and “nuclear terrorism”. The 2010s witnessed a shift in the central challenges at the heart of the nuclear order.
The third nuclear age is characterised by great power nuclear competition, coupled with greater manoeuvring by “middle powers” to ensure a spot in the transforming international order. This was coupled with massive technological innovation involving the diffusion of non-nuclear weapons for strategic missions. The ‘golden age of nuclear arms control’, which witnessed various bilateral and international arms control treaties during 1987-2000, gradually waned.
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A fractured nuclear order
Today’s world has become more complex. The old architecture of arms control is collapsing. With the demise of the Intermediate-Range Nuclear Forces (INF) Treaty, the Treaty on the Prohibition of Nuclear Weapons (TPNW) remains largely symbolic, rejected by all nuclear-armed states. The uncertain future of the New Strategic Arms Reductions Treaty (New START)—the last surviving pillar of the nuclear arms control framework—indicates that the future is bleak.
Meanwhile, the race for nuclear weapons, once thought a relic of the Cold War, has resurfaced. According to the Stockholm International Peace Research Institute (SIPRI) Yearbook 2025, nuclear-weapon states are investing heavily in the expansion of their arsenal, along with the modernisation of delivery vehicles. These states are focusing on developing dual-capable missiles and sophisticated Multiple Independently-targetable Re-entry Vehicle (MIRV) technology, blurring the distinction between conventional and nuclear warfare.
China is quietly building capabilities such as a comprehensive early warning system, including infrared satellites and ground-based radars. This raises scepticism regarding Beijing changing its nuclear launch strategy to “launch under attack”. Russia’s revised nuclear doctrine lowers the threshold for using its nuclear weapons. These developments reflect a fractured nuclear order, which is then complicated by technological advancements.
How technology affects deterrence
Unlike in previous eras, deterrence dynamics in the third nuclear age are not shaped by nuclear weapons alone. The sophistication in technologies is transforming the character of conflict. The use of strategic non-nuclear weaponry, such as conventionally armed precision-strike missiles and anti-satellite or anti-submarine warfare capabilities, is not associated with a taboo, as nuclear weapons are. This makes non-nuclear weapons more “usable” in crisis situations. With increasing dual-use technologies such as space-based surveillance systems and dual-capable missiles, any attack poses the risk of “conventional-nuclear entanglement” that might result in inadvertent nuclear escalation.
Advanced cyber and AI platforms integrated in military command and control systems decrease the reaction time and increase the chances of miscalculation.
Hypersonic weapons add another layer of complexity and instability. These weapons are capable of travelling at more than five times the speed of sound and are highly manoeuvrable, making them extremely hard to intercept with traditional missile defence systems. Countries are investing heavily in hypersonic technology, with Russia and China already possessing hypersonic glide vehicles. Their deployment compresses the decision-making time and increases the risk of a pre-emptive strike in panic. The speed and strike with little warning can make the adversary assume the “worst-case scenario”, potentially leading to nuclear escalation.
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Reimagining restraint
The sobering reality of today is that nuclear danger has not gone away. The current nuclear order is multipolar, and as regional nuclear dynamics heat up, deterrence relationships are being tested by border tensions and military modernisation of adversaries.
The deterrence stability of the Cold War era resided in predictability and communication. Today, it is drifting toward the risk of miscalculation and inadvertent escalation. There is a need for more dialogue and cooperation. China’s decision to opt out of the ‘blueprint for action’ agreement at the Responsible Use of AI in Military Domain (REAIM) summit in Seoul last year highlights that there is a long way to go for countries to come together over issues involving the warfare-technology nexus.
Reimagining restraint through transparency and confidence-building measures is imperative to ensure that history does not repeat itself as tragedy.
Alisha is a PhD student, Diplomacy and Disarmament at the School of International Studies, Jawaharlal Nehru University. Her X handle is @Alisha28046943. Views are personal.
(Edited by Prasanna Bachchhav)