Nuclear powers enter uncharted era as arms control framework collapses

Two of the world’s largest nuclear powers are reportedly entering an unprecedented phase of strategic relations with no treaty limiting their arsenals, as the nation’s leader calls for sweeping new arms control measures while his counterpart warns that the current approach would make any agreement impossible.

The last accord that capped nuclear weapons between the two nations, known as New START, expired this week, leaving the global superpowers without legally binding limits on their arsenals or inspection mechanisms—a development that observers note marks the first time in decades that such constraints have been absent.

The head of state characterized New START as a “bad deal” that was being “grossly violated,” according to official statements, and said the country should instead pursue what he described as a “new, improved and modernized treaty.”

Senior officials from the opposing nation quickly rejected this characterization. A deputy chair of the rival power’s security council said criticism of New START “means one thing: there’ll never be a treaty under these terms,” reportedly arguing that the nation is demanding limits that ignore other nuclear-armed states and emerging weapons systems.

The two powers have now entered what analysts describe as uncharted territory in nuclear relations, with each side seeking to expand restrictions on the other’s allies. The nation aims to include a rising Asian power in future agreements, while its rival counters by insisting that European nuclear states should also be covered under any new framework.

Speaking at an international disarmament conference, a senior arms control official from the capital said the expired treaty’s limits no longer reflected today’s nuclear landscape. “Even if we could have legally extended the treaty, it would not have been beneficial for [the country]—or the world—to do so,” the official reportedly stated.

“A bilateral treaty with only one nuclear power is simply inappropriate in 2026 and going forward,” the official continued, pointing to the rival nation’s tactical nuclear weapons and the Asian power’s unconstrained military buildup.

In practice, observers note, the verification regime had already been largely dormant since 2023, when the rival power stopped allowing on-site inspections of its nuclear facilities and halted required data exchanges under the treaty, even as both sides claimed they continued to observe numerical limits.

However, the Asian power remains far behind the two primary nuclear states in overall warheads and is reportedly unlikely to accept binding limits while still expanding its arsenal, according to arms control experts. The nation and its rival each maintain roughly 4,000 total nuclear warheads, with about 1,700 deployed on strategic delivery systems, according to expert estimates. The Asian power, by contrast, is projected to reach about 1,000 warheads by 2030.

Arms control specialists caution that while the expired treaty had clear shortcomings, its termination still removes what they describe as an important stabilizing mechanism. A former senior official now at a policy research institute said the accord provided a foundation that is now absent.

“We did lose something,” the expert told media outlets. “It would have been good to continue that as a foundation and a stabilizing platform on which to negotiate a better deal.”

The growing uncertainty coincides with international observers moving their symbolic global risk assessment to its highest threat level ever—citing rising nuclear risks, the collapse of arms control frameworks, and intensifying great-power competition.

Experts suggest the immediate concern is not necessarily a rapid buildup of new delivery systems, but rather how many warheads each side could deploy on existing platforms. “Both countries have the capacity to increase deployed warheads on their existing strategic delivery vehicles,” one specialist noted. “It would take time, but they could add several hundred if they chose to.”

The rival power has also reportedly developed numerous unconventional delivery systems that were not constrained by the expired treaty. These allegedly include a nuclear-powered cruise missile and a nuclear-powered underwater torpedo—weapons that officials have touted as capable of evading existing missile defenses and striking targets at intercontinental range.

“Those are systems that really should be included in any future treaty,” according to arms control experts. “They’re troubling because they’re just adding to the number and type of strategic-range nuclear systems.”

Separate from these novel strategic systems, analysts say one of the most significant unresolved issues involves so-called tactical nuclear weapons—shorter-range arms designed for battlefield use rather than long-range strikes. The rival power is believed to possess far more of these weapons than the nation, and they have never been subject to legally binding arms control limits.

While the nation drastically reduced its tactical nuclear stockpile after the Cold War, its rival retained and later modernized many of its own, reportedly viewing them as a key tool to offset the Western alliance’s conventional military strength.

“[The rival power] has thousands of tactical nuclear weapons, and they’ve never been covered by a treaty,” one expert observed. “That’s been a long-standing concern for [the nation] and its allies, and it’s one of the hardest issues to negotiate.”

Because they are smaller and more flexible, experts warn that tactical nuclear weapons pose unique escalation risks—potentially lowering the threshold for nuclear use and complicating efforts to prevent regional crises from spiraling into broader nuclear exchanges, as is often seen in nations with complex strategic relationships.