The new nuclear arms race

The world is once again entering a nuclear arms race—less theatrical than that of the Cold War, yet in many ways more dangerous. The original contest between the United States and the Soviet Union, formalised through doctrines of deterrence and mutually assured destruction, was at least constrained by arms control treaties and a measure of predictability. The new nuclear competition unfolding in the 2020s is far more multipolar, fragmented and technologically unstable. It involves not two superpowers but a dozen states, each with distinct security concerns, strategic doctrines and emerging capabilities in artificial intelligence, hypersonic delivery systems and low-yield nuclear weapons.

The first cause of this renewed race lies in the erosion of arms control architecture. The United States’ withdrawal from the Anti-Ballistic Missile Treaty in 2002, Russia’s suspension of the New START Treaty in 2023, and the collapse of the Intermediate-Range Nuclear Forces Treaty have dismantled the scaffolding that for decades kept nuclear competition within bounds. Verification regimes have decayed; data exchanges have ceased. What remains is a world of opacity, suspicion and speculation, in which every technological development by one state prompts a counter-measure by another.

Russia’s war in Ukraine has accelerated this descent. Moscow’s repeated nuclear threats, thinly veiled references to tactical use, and deployment of nuclear weapons to Belarus have normalised the public discussion of nuclear options. The psychological barrier that kept nuclear weapons as political instruments rather than usable arms is being eroded. Simultaneously the United States and her NATO allies are reconsidering their nuclear postures, with Washington modernising its B61 gravity bombs and extending the life of its Ohio-class submarine fleet. The United Kingdom is increasing the cap on her warheads, while France quietly invests in next-generation nuclear-armed cruise missiles. China, meanwhile, is expanding her arsenal at an unprecedented pace, constructing hundreds of new missile silos and diversifying her strategic triad.

The second cause of the new arms race is the advent of new delivery and control technologies. Hypersonic glide vehicles—capable of manoeuvring within the atmosphere at speeds exceeding Mach 5—compress decision times and undermine traditional missile defences. Both Russia and China have tested operational systems, while the United States, India and even North Korea are investing heavily in parallel programmes. These weapons blur the line between conventional and nuclear payloads, risking catastrophic misinterpretation in a crisis. At the same time, developments in artificial intelligence and autonomous command-and-control systems promise faster response capabilities but also introduce new vulnerabilities: algorithmic errors, cyber intrusion, or the automation of launch authority could precipitate a disaster no human ever intended.

Thirdly, regional rivalries are now nuclearised. India and Pakistan remain locked in a volatile balance punctuated by cross-border skirmishes and militant incursions. North Korea’s expanding arsenal and delivery range bring Tokyo, Seoul and even parts of the continental United States within reach. Israel’s opaque but widely acknowledged deterrent shapes the calculus of Iran, whose own nuclear ambitions continue to haunt the Middle East. The once clear hierarchy of global nuclear power is fragmenting into multiple overlapping theatres of deterrence—each governed by different risk tolerances and command cultures.

The danger of this pluralism is that traditional deterrence theory depends upon rationality and stable communication. During the Cold War, Washington and Moscow shared a mutual understanding of nuclear thresholds and the logic of escalation control. In the present era, such understandings are absent. The risk of inadvertent escalation, fuelled by miscalculation or technological error, has never been higher. Moreover, the introduction of low-yield tactical nuclear weapons lowers the threshold for potential use. Russia’s doctrine now explicitly contemplates limited nuclear strikes to “de-escalate” conventional conflicts—an inversion of the very principle that once restrained them.

Meanwhile the global non-proliferation regime is faltering. The Treaty on the Non-Proliferation of Nuclear Weapons (NPT) struggles to maintain credibility when its principal signatories themselves expand or modernise their arsenals. The Comprehensive Nuclear-Test-Ban Treaty remains unratified by key states. New aspirants, observing the fates of Libya and Ukraine—both of which surrendered nuclear capabilities or ambitions and were later attacked—see nuclear weapons as the ultimate guarantor of sovereignty.

Yet the new nuclear race differs from the old one in its economics and its secrecy. Whereas the Cold War arms race was a vast public spectacle - ballistic missile parades, national propaganda and declared deterrence postures - the contemporary competition is hidden in research budgets and military laboratories. Modernisation programmes are justified as replacements for “obsolete systems,” not as escalation. The financial cost, however, remains enormous: the United States alone is projected to spend over a trillion dollars in the next thirty years to refurbish her nuclear forces. China’s spending, although opaque, may be comparable.

What makes the situation especially perilous is that nuclear arms are being integrated into an increasingly unstable international order. The norms of restraint that governed major-power relations after 1945 are collapsing. The United Nations Security Council is paralysed by vetoes; the Conference on Disarmament has been moribund for decades. In such an environment, nuclear weapons regain not merely their deterrent function but also their symbolic and coercive power.

Nevertheless there remain faint prospects for restraint. Even amidst hostility, Moscow and Washington could revive limited dialogue on verification and crisis communications, as they did during the darkest Cold War years. The P5 nuclear states could reaffirm the principle that “a nuclear war cannot be won and must never be fought”. Confidence-building measures—such as notifications of missile tests, reciprocal inspections, or the re-establishment of hotlines—would help restore predictability. Civil society, scientific communities and non-nuclear states must press their governments to resist a drift towards nuclear normalisation.

The new nuclear arms race is not inevitable, but it is accelerating. Its participants are more numerous, its technologies more destabilising, and its political context more fractured than ever before. Humanity has entered a second nuclear age without the cautionary memory that once restrained her leaders. Unless wisdom returns to international politics, the world may soon find itself once again living by the terrifying logic of deterrence, hoping that fear alone will preserve her from annihilation.