After midnight on February 5, 2026, the world will enter a nuclear era without precedent in more than half a century. The New Strategic Arms Reduction Treaty (New START) — the final remaining nuclear arms control agreement between the United States and Russia — will formally expire, leaving the world’s two largest nuclear powers unconstrained by any legally binding limits on their strategic arsenals.
For the first time since the early 1970s, when the first Strategic Arms Limitation Talks (SALT) agreements were negotiated at the height of the Cold War, Washington and Moscow will operate without treaty-based ceilings on deployed nuclear weapons, delivery systems, or launchers. The end of New START comes amid deeply fractured U.S.-Russia relations, an ongoing war in Ukraine, renewed great-power competition, and rising global instability — a convergence that many analysts describe as profoundly dangerous.
The gravity of the moment has been underscored by the Bulletin of the Atomic Scientists, which has moved its symbolic Doomsday Clock closer to “midnight” than ever before. The Clock now stands at 85 seconds to midnight, the closest it has been in its 78-year history, signaling what the organization describes as an unprecedented level of global risk.
“The Doomsday Clock’s message cannot be clearer,” said Alexandra Bell, president and CEO of the Bulletin of the Atomic Scientists. “Catastrophic risks are on the rise, cooperation is on the decline, and we are running out of time. Change is both necessary and possible, but the global community must demand swift action from their leaders.”
The Doomsday Clock is set annually by the Bulletin’s Science and Security Board, in consultation with its Board of Sponsors, which includes eight Nobel laureates. In 2026, the decision to move the Clock closer to midnight was driven by what the group described as compounding global threats: intensifying nuclear risks, rapid advances in artificial intelligence, biological security concerns, and the accelerating climate crisis.
While the Bulletin’s annual statement addresses a wide range of existential dangers, nuclear weapons remain central to its warning. The collapse of arms control frameworks — once the backbone of strategic stability between nuclear superpowers — has emerged as one of the most alarming trends.
“In 2025, it was almost impossible to identify a nuclear issue that got better,” said Jon B. Wolfsthal, director of global risk at the Federation of American Scientists (FAS) and a member of the Bulletin’s Science and Security Board. “More states are relying more intently on nuclear weapons, multiple states are openly talking about using nuclear weapons not only for deterrence but for coercion.”
Wolfsthal noted that hundreds of billions of dollars are being spent worldwide to modernize and expand nuclear arsenals, while an increasing number of non-nuclear states are reconsidering their long-standing commitments to remain weapon-free. “Instead of stoking the fires of the nuclear arms competition, nuclear states are reducing their own security and putting the entire planet at risk,” he said.
New START was signed on April 8, 2010, in Prague by then U.S. President Barack Obama and Russian President Dmitry Medvedev. It entered into force in February 2011, replacing the 2002 Strategic Offensive Reductions Treaty (SORT), which had set looser limits on deployed warheads.
The treaty was widely regarded as a cornerstone of post-Cold War strategic stability. It imposed strict, verifiable limits on the most destructive weapons ever created and introduced a robust inspection and transparency regime designed to prevent misunderstandings and worst-case planning.
Under New START, each side was limited to:
700 deployed intercontinental ballistic missiles (ICBMs), submarine-launched ballistic missiles (SLBMs), and nuclear-capable heavy bombers
1,550 nuclear warheads deployed on those platforms
800 deployed and non-deployed launchers, including missiles and bombers
These reductions were fully implemented by February 5, 2018. The treaty also mandated twice-yearly exchanges of detailed data on nuclear forces and allowed for short-notice, on-site inspections — an unprecedented level of transparency that gave each side valuable insight into the other’s nuclear posture.
Originally negotiated for a 10-year term, New START was extended in 2021 for a final five-year period, making its expiration in 2026 both predictable and deeply consequential.
Verification Collapse Before Expiration
In practice, New START began unraveling well before its formal end. In February 2023, Russia announced that it was suspending its participation in the treaty’s verification mechanisms, citing tensions with the United States over the war in Ukraine. Moscow halted on-site inspections and data exchanges, effectively neutralizing the treaty’s transparency provisions.
Despite this, Russian officials insisted that Moscow would continue to observe the treaty’s numerical limits. That pledge, while unverifiable, helped prevent a sudden collapse in strategic restraint and avoided the most destabilizing forms of nuclear signaling.
Even with verification suspended, New START continued to exert a stabilizing influence. Since the height of the Cold War in the mid-1980s, the global nuclear stockpile has shrunk dramatically — from approximately 70,400 warheads in 1986 to about 12,500 today — largely due to successive arms control agreements beginning with SALT and culminating in New START.
With the treaty’s expiration, those restraints may disappear entirely.
Rapid Expansion Potential
Analysts warn that the absence of legal limits could allow both Washington and Moscow to rapidly increase their deployed nuclear forces. Estimates suggest that Russia could raise its deployed warheads by as much as 60 percent, while the United States could potentially more than double its deployed arsenal — an increase of over 110 percent — within months.
Both countries possess missiles and bombers capable of carrying more warheads than they currently deploy. Uploading additional warheads would require little technological innovation and could be done quickly, fundamentally altering the global strategic balance.
The risk is not merely numerical. An unconstrained arms race could fuel worst-case threat assessments, shorten decision-making timelines, and increase the likelihood of miscalculation — especially during crises.
Further complicating the strategic environment are ambitious weapons programs on both sides. U.S. President Donald Trump has outlined plans to accelerate advanced missile defense capabilities under the so-called “Golden Dome” initiative, aimed at intercepting a wide range of missile threats, including nuclear-armed systems.
Russia, for its part, has highlighted new strategic weapons designed to bypass missile defenses. President Vladimir Putin has unveiled systems such as the Burevestnik, a nuclear-powered, nuclear-armed cruise missile with theoretically unlimited range, and the Poseidon, a nuclear-powered underwater drone capable of delivering massive nuclear payloads against coastal targets.
Many experts fear that the interaction between expanding missile defenses and exotic offensive systems could undermine strategic stability by weakening mutual deterrence — the fragile balance that has prevented nuclear war for decades.
The timing of New START’s expiration is also troubling in diplomatic terms. It comes just months before the 2026 Review Conference of the Nuclear Non-Proliferation Treaty (NPT), the cornerstone of the global non-proliferation regime.
The NPT rests on a bargain: non-nuclear states agree not to acquire nuclear weapons, while nuclear-weapon states commit to pursuing disarmament and arms control. The collapse of the last bilateral arms control treaty between the world’s two largest nuclear powers threatens to deepen skepticism among non-nuclear states about whether that bargain is still being honored.
Many diplomats fear that the end of New START will exacerbate divisions between nuclear and non-nuclear states, weaken the credibility of the NPT, and embolden proliferation pressures in volatile regions.
Despite the bleak outlook, some room for optimism remains. President Putin has proposed extending observance of New START’s numerical limits beyond the treaty’s expiration, even in the absence of formal verification.
In September last year, Putin suggested that both sides voluntarily adhere to the treaty’s three core limits — 700 deployed delivery systems, 800 total launchers, and 1,550 deployed warheads — for an additional year, until February 2027. In November, a senior Russian foreign ministry official indicated that Moscow might be willing to extend those limits further.
President Trump, for his part, has sent mixed signals. In July, he said he did not want New START to expire, and when asked about Putin’s proposal, he remarked, “It sounds like a good idea to me.”
However, Trump later complicated the picture by insisting that any future arms control agreement must include China. “If it expires, it expires,” he told the New York Times, adding that he would prefer a “better” deal that ideally incorporates Beijing.
While China’s nuclear arsenal is growing, experts note that it remains far smaller than those of the United States and Russia — less than 12 percent the size of the U.S. arsenal and under 11 percent of Russia’s. There is also no precedent for trilateral nuclear arms control negotiations, and Beijing has repeatedly shown little interest in joining such talks.
Many analysts argue that making China’s participation a precondition effectively guarantees paralysis at a moment when restraint is urgently needed.
Viewed in this light, experts say the most realistic path forward is to build on Moscow’s proposal for continued adherence to New START’s limits, even informally, while seeking incremental confidence-building measures that could lay the groundwork for future agreements.
For now, Russian officials say they are waiting for a response from Washington. The clock, both literal and metaphorical, continues to tick.
As the last surviving pillar of Cold War-era arms control collapses, the world is left confronting a sobering reality: the safeguards that once kept nuclear competition in check are eroding, and the responsibility to prevent catastrophe rests once again on political will rather than binding law.
