For the first time in decades, the world’s largest nuclear powers are operating without hard caps on their arsenals just as more countries flirt with the bomb. The expiration of New START on February 5, 2026 removed the last binding ceiling on deployed U.S. and Russian warheads, even as global stockpiles hover around 12,100 and trend upward. The result is a system that looks less like a stable balance and more like a crowded highway where the speed limit signs have been ripped out.
In this new environment, the traditional arms control playbook is colliding with a wave of regional insecurity from the Middle East to East Asia. The core risk is not only that the United States, Russia and China expand their arsenals, but that anxious middle powers decide the safest place is inside the nuclear club rather than under treaties that no longer feel credible.
The end of limits for the top nuclear powers
When New START expired, it took with it decades of legally binding ceilings that had helped drive global arsenals down from Cold War peaks in the 1980s to roughly 12,000 today. Analysts note that earlier frameworks had forced deep cuts in deployed strategic weapons, but the latest lapse means Russia and the now face no enforceable caps on how many warheads they can field. That shift matters because these two countries still hold the overwhelming share of the world’s nuclear firepower, and their choices set the tone for everyone else.
As of 2026, the nine nuclear-armed states together possess approximately 12,100 warheads, with about 9,600 in stockpiles and 3,900 deployed on missiles or aircraft. According to one detailed Overview, that total sits in fewer hands than many assume, and the two largest arsenals still belong to the United States and Russia. A separate assessment stresses that “Most the” world’s approximately 12,100 nuclear weapons are held by just a handful of major powers, with Russia and the United States accounting for the lion’s share of that total and other states like France, the United Kingdom, Pakistan, India, North Korea and Israel maintaining far smaller forces.
China’s rise and a three-way arms race
The collapse of bilateral limits would already be destabilizing in a two-player game, but it is happening just as China accelerates its own buildup. According to one recent visualization, According to SIPRI and FAS, Beijing’s arsenal reached approximately 600 warheads by early 2026, up from just a few hundred a decade ago. That trajectory suggests that China is no longer content with a minimal deterrent and is instead edging toward a force that can compete with both Washington and Moscow across land, sea and air.
Strategists warn that this three-way dynamic could produce a “worst case” spiral in which each capital plans for the most threatening scenario and uploads additional warheads accordingly. One expert quoted in a recent analysis argued that if the United States increases its deployed weapons out of fear of Russian moves, Moscow is likely to respond in kind, creating a domino effect that also factors in Chinese capabilities. A separate profile of Beijing underscores that its leadership sees nuclear modernization as part of a broader push to match or surpass U.S. power in the Indo-Pacific, which further complicates any attempt to revive traditional arms control formats that were built for a bipolar world.
Arms control’s long erosion and the New START shock
The end of New START did not come out of nowhere. Arms control has been eroding for years, with key agreements either collapsing or being abandoned. In 2019, the United States unilaterally withdrew from the Intermediate Range Nuclear Forces Treaty, removing a central pillar that had banned an entire class of ground-launched missiles. Analysts argue that this pattern of withdrawals and violations has steadily chipped away at the trust needed to negotiate new limits, leaving New START as a lonely holdout until its own expiration.
Nonproliferation experts describe the New START Treaty’s end as a hinge moment because it was the last remaining nuclear arms control agreement between the Unit and Russia that imposed verifiable caps on deployed strategic warheads. A statement from senior lawmakers on the House Foreign Affairs Committee warned that the New START Treaty had been central to strategic stability and urged both sides to negotiate a legally binding successor. Nuclear policy specialists also note that, according to one detailed Background analysis, decades of agreements had helped cut global arsenals from Cold War highs in the 1980s to roughly 12,000 today, so losing the last of those deals is not a technical footnote but a structural shock to the system.
Middle powers on the edge: Iran, South Korea and Saudi Arabia
While the big three expand their options, the more immediate danger may come from states that do not yet have nuclear weapons but increasingly look like they could. There are currently nine sovereign states that are generally understood to possess nuclear weapons, a list that includes the United States, Russia, the United Kingdom, France, China, India, Pakistan, North Korea and Israel, according to a widely cited There entry. The concern now is that countries such as Iran, South Korea and Saudi Arabia, each facing its own security dilemmas, could push that number higher and strain the already fragile non-proliferation regime.
Nonproliferation specialists warn that enrichment and reprocessing capabilities pose a particular risk because they can be used to produce either reactor fuel or weapons material. One detailed assessment notes that Enrichment and related technologies are spreading as states seek energy independence and commercial advantage, which in turn lowers the technical barriers to proliferation. In 2026, Iran’s nuclear program remains a central concern, with analysts highlighting how Iran has expanded its enrichment capacity and shortened its potential breakout time, even as diplomatic efforts to restore earlier limits have stalled.
In East Asia, the debate is shifting from whether U.S. guarantees are sufficient to whether national nuclear options are necessary. A recent legal and policy review notes that in 2026, both South Korea and Japan are expanding their civilian nuclear industries in ways that could, if political decisions changed, support weapons programs. Public opinion polling in South Korea has shown rising support for an indigenous deterrent in response to North Korea’s growing arsenal, and some lawmakers in Seoul now openly discuss the option. In the Gulf, analysts point out that Saudi Arabia has signaled interest in nuclear technology and could contemplate nuclear weapon development if it perceives Iran crossing the threshold, a concern echoed in profiles of Saudi Arabia that highlight its regional rivalry with Tehran.
Europe’s nuclear anxiety and the myth of automatic stability
Europe, long accustomed to relying on U.S. extended deterrence and NATO’s nuclear sharing, now finds itself in a more ambiguous landscape. Analysts note that in the face of the increasing unreliability of U.S. security commitments, Europeans are preparing to address their own nuclear security more directly, debating options that range from deeper reliance on French and British forces to discussions of a shared European deterrent. That conversation is no longer confined to think tanks; it is seeping into mainstream politics in Berlin, Warsaw and other capitals that sit closer to Russia’s conventional and nuclear forces.
Some commentators argue that the end of New START simply reflects a reality in which arms control had already lost much of its bite, and that technological advances make traditional counting rules less relevant. One influential newsletter framed the moment bluntly, noting that on Thursday, 5 February, New START Treaty that capped Russian and U.S. strategic warheads is now gone, but argued that a new arms race is not inevitable. I think that view underestimates how much psychological reassurance those limits provided to allies and rivals alike. When you remove the speed limit signs, some drivers may still go the same pace, but others will push the accelerator, and everyone else has to decide whether to keep up or get out of the way.
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*This article was researched with the help of AI, with human editors creating the final content.
