The world may be standing on the brink of a new and more dangerous arms race, one unlike the Cold War competition of the 20th century. The imminent expiration of the New Strategic Arms Reduction Treaty (New START)—the last remaining nuclear weapons control agreement between the United States and Russia—has triggered alarm among security experts, diplomats, and military leaders.
Signed in 2010, New START symbolized the final pillar of arms control cooperation between Washington and Moscow. Its collapse not only removes limits on the world’s two largest nuclear arsenals but also signals a profound shift toward a less regulated, more volatile global security environment.
The question is no longer whether arms control is weakening—but whether the next phase of the arms race has already begun.
What Was New START—and Why It Mattered
The New START treaty, signed in Prague in 2010, capped the number of deployed strategic nuclear warheads at 1,550 per country. It also introduced crucial transparency mechanisms, including:
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Data exchanges
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Notifications of deployments
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On-site inspections
These measures reduced the risk of miscalculation, mistrust, and accidental escalation, particularly during moments of crisis.
New START was the successor to the original START treaty of 1991, signed by the United States and the Soviet Union, which limited each side to 6,000 nuclear warheads. Together, these agreements played a central role in ending the Cold War arms buildup.
With New START expiring, there will be no legally binding limits on US and Russian nuclear arsenals for the first time in more than 50 years.
A Pattern of Collapse: Arms Control Unravelling
The expiration of New START does not occur in isolation. It follows a troubling pattern of arms control treaties falling apart, including:
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The Intermediate-Range Nuclear Forces (INF) Treaty, which eliminated short- and medium-range nuclear weapons in Europe
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The Open Skies Treaty, which allowed unarmed surveillance flights to build military transparency
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The Conventional Armed Forces in Europe (CFE) Treaty, limiting tanks, troops, and artillery
Britain’s former Chief of the Defence Staff, Admiral Sir Tony Radakin, has warned that the global security architecture that kept the world safe for decades is now “at risk of unravelling.”
He described the collapse of arms control frameworks as one of the most dangerous trends in modern global security, alongside the growing prominence of nuclear weapons.
Russia and the US: Responsibility or Rearmament?
Although Russia formally suspended participation in New START three years ago amid rising tensions over Ukraine, both sides were widely believed to be informally adhering to its limits.
Now, Moscow has made clear that once the treaty expires, it considers itself no longer bound by any obligations. The Russian foreign ministry stated that while it intends to act “responsibly and in a balanced manner,” it also remains ready to take “decisive military-technical measures” to counter perceived threats.
This warning is striking given that even Dmitry Medvedev, who signed the treaty as Russia’s president in 2010 and has since adopted aggressive rhetoric, called its expiration something that should “alarm everyone.”
On the US side, President Donald Trump has shown little urgency, stating bluntly:
“If it expires, it expires… We’ll just do a better agreement.”
However, no such agreement currently exists—and there is little evidence that negotiations are imminent.
China, Europe, and the Expansion Problem
One major obstacle to a new arms control deal is who should be included.
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Washington insists that any future treaty must include China, whose nuclear arsenal is rapidly expanding.
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Moscow, meanwhile, argues that France and the UK, Europe’s nuclear powers, should also be part of any agreement.
This widening circle of nuclear stakeholders makes negotiations exponentially more complex. What was once a bilateral US–Russia framework is now evolving into a multipolar nuclear competition.
A New Arms Race Is Already Underway
According to Darya Dolzikova, Senior Research Fellow at the Royal United Services Institute (RUSI), the expiration of New START is especially concerning because “there are drivers on both sides to expand their strategic capabilities.”
Both the US and Russia are modernizing their nuclear forces. This includes:
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New delivery systems
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Enhanced warhead capabilities
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Improved missile defenses
Russia, in particular, has expressed concerns about its ability to penetrate US missile defense systems—concerns amplified by Trump’s proposal to build a “Golden Dome” missile shield over North America.
Next-Level Weapons: Hypersonics and Nuclear Drones
Unlike Cold War arms races focused largely on numbers, the next phase is about technological superiority.
Russia has developed advanced systems designed to bypass missile defenses, including:
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Poseidon, a nuclear-powered, nuclear-armed underwater autonomous torpedo
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Burevestnik, a nuclear-powered cruise missile with potentially unlimited range
Meanwhile, the US, Russia, and China are all racing to deploy hypersonic missiles, capable of traveling at speeds exceeding 4,000 mph while maneuvering unpredictably—making them extremely difficult to intercept.
These systems blur the line between conventional and nuclear warfare, increasing the risk of misinterpretation during crises.
The Growing Salience of Nuclear Weapons
Another disturbing trend is the renewed appeal of nuclear weapons as deterrents.
Rather than declining, nuclear weapons are gaining strategic prominence. According to experts, more countries appear interested in nuclear capabilities, while existing nuclear powers are placing greater emphasis on them in military planning.
Dolzikova warns that this growing reliance on nuclear deterrence will only make future arms control agreements harder to achieve.
Diplomacy on Pause
Despite the risks, there is little diplomatic momentum. The issue was discussed when Vladimir Putin met Donald Trump in Alaska last year, but no breakthrough occurred.
Pope Leo has publicly urged both countries to renew the treaty, warning that the global situation requires “doing everything possible to avert a new arms race.” His appeal reflects broader international anxiety—but moral pressure alone may not be enough.
Entering a More Dangerous Era
The expiration of New START marks a turning point in global security. It does not merely end a treaty—it ends an era of predictability, transparency, and restraint between the world’s two largest nuclear powers.
A new arms race is not only likely—it is already underway. But this time, it is more complex, faster, and more technologically advanced than anything seen before.
Without renewed arms control efforts, the world is heading toward a next-level arms race, defined not by limits and inspections, but by hypersonic speed, autonomous weapons, and strategic uncertainty.
The question now is not whether the arms race has begun—but whether global leaders can still prevent it from spiraling out of control.
