The Last Russia-US Nuclear Treaty Is About to Expire: What Happens Next

As the world moves closer to February 5, 2026, a major pillar of global security is quietly approaching its end. The New Strategic Arms Reduction Treaty (New START) — the last remaining nuclear arms control agreement between the United States and Russia — is set to expire. Its potential collapse marks a turning point not just for the two nuclear superpowers, but for the entire international system.
For decades, nuclear treaties helped prevent unchecked arms races and reduced the risk of catastrophic conflict. With New START hanging by a thread, many are asking a critical question: what happens when the last safety net disappears?
What Is New START and Why Does It Matter?
New START was signed in 2010 and came into force in 2011. It placed legally binding limits on the strategic nuclear arsenals of the United States and Russia — the two countries that together possess nearly 90 percent of the world’s nuclear weapons.
Under the treaty, each side agreed to limit itself to:
1,550 deployed nuclear warheads
700 deployed delivery systems, such as intercontinental ballistic missiles (ICBMs), submarine-launched ballistic missiles (SLBMs), and strategic bombers
But New START was not just about numbers. Its real strength lay in transparency and verification. Regular data exchanges, on-site inspections, and notifications ensured both sides knew what the other was doing. This reduced suspicion, prevented misunderstandings, and lowered the risk of accidental escalation during times of tension.
In an era marked by distrust, New START functioned as a stabilizing force.
Why Is the Treaty in Trouble Now?
The geopolitical environment that allowed New START to exist has drastically changed. Relations between Washington and Moscow are at one of their lowest points since the Cold War.
Several factors have pushed arms control to the sidelines:
The war in Ukraine has shattered diplomatic trust between Russia and the West.
Russia suspended participation in treaty inspections, claiming security concerns and political pressure.
The United States insists that meaningful arms control requires full compliance and verification.
Broader disagreements over NATO, sanctions, and global influence have poisoned the negotiating atmosphere.
Although both countries have occasionally signaled interest in restraint, no formal talks on a successor treaty have made meaningful progress.
Why Hasn’t a New Treaty Been Negotiated?
Arms control negotiations are complex even in good times. In today’s environment, they are especially difficult.
Russia has argued that any future agreement must include other nuclear powers, particularly the United Kingdom and France. The U.S. rejects this, stating that it cannot negotiate limits on behalf of its allies.
Meanwhile, China has refused to join trilateral talks, pointing out that its nuclear arsenal is far smaller than those of the U.S. and Russia. Beijing argues that expecting equal limits is unfair and strategically unrealistic.
As a result, the world is facing a rare and dangerous moment: the possible end of all legally binding nuclear limits between the two largest nuclear powers.
What Happens If New START Expires?
If the treaty expires without extension or replacement, the immediate effects may not be visible — but the long-term consequences could be profound.
1. No Legal Constraints on Nuclear Weapons
For the first time in over 50 years, there would be no binding limits on U.S. and Russian strategic nuclear arsenals. While neither side is expected to instantly build thousands of new warheads, the absence of rules opens the door to future expansion.
This creates a strategic environment driven more by worst-case assumptions than mutual restraint.
2. Increased Risk of Miscalculation
Without inspections and data sharing, uncertainty grows. When countries lack reliable information about each other’s capabilities, they tend to assume the worst. In times of crisis, this uncertainty can be deadly.
History shows that misunderstandings — not intentions — often trigger conflict.
3. Damage to Global Non-Proliferation Efforts
The collapse of New START would weaken the credibility of the Nuclear Non-Proliferation Treaty (NPT). Non-nuclear states may question why they should uphold their commitments if nuclear powers abandon restraint.
This could encourage other countries to pursue nuclear capabilities, increasing global instability.
4. A New Arms Race
Even without immediate buildup, the absence of limits could gradually lead to a new nuclear arms race — one driven by emerging technologies such as hypersonic missiles, advanced missile defenses, and space-based systems.
Unlike the Cold War, this arms race would unfold in a multipolar world, making it even harder to control.
Is There Any Hope for an Extension?
There is still a narrow window for action.
Russia has floated the idea of temporarily adhering to New START limits, provided the United States does the same. This would not be a full extension but could prevent immediate deterioration.
Such a move would buy time — time for diplomacy, trust-building, and perhaps the groundwork for a future agreement. However, temporary measures are fragile and lack the enforceability of a formal treaty.
What Comes After New START?
If New START ends, the world enters uncharted nuclear territory. Future arms control may look very different from the treaties of the past. Instead of comprehensive agreements, we may see:
Informal political commitments
Partial or regional agreements
Confidence-building measures without legal force
While these alternatives are better than nothing, they lack the strength and reliability of binding treaties.
A Defining Moment for Global Security
The expiration of the last Russia-US nuclear treaty is more than a technical event. It is a symbol of a world moving away from cooperation and toward strategic rivalry.
Whether this moment becomes the start of a dangerous new arms race — or a catalyst for reinventing arms control — depends on political will. History shows that dialogue is possible even in times of deep hostility.
The question now is simple, yet urgent: Will the world choose restraint — or risk repeating the most dangerous mistakes of the past?