By Tariq Rauf*
VIENNA | 10 November 2025 (IDN) — On 26 September 1996, on the floor of the United Nations General Assembly, at the signing ceremony for the Comprehensive Nuclear-Test Ban Treaty (CTBT), then-US President William J. Clinton declared the treaty as “the longest-sought, hardest fought prize in arms control history.”
He exaggerated; in reality, the longest-sought, hardest fought prize in nuclear arms control history remains to be won. It is nuclear disarmament and the elimination of nuclear weapons, as called for in the very first resolution adopted by the-then newly established UN General Assembly on 24 January 1946.
The nuclear Non-Proliferation Treaty (NPT), the CTBT, a global treaty prohibiting the production of weapon-usable nuclear materials (including elimination of existing stocks of such materials), along with the Treaty on the Prohibition of Nuclear Weapons (TPNW) and regional nuclear-weapon-free zone treaties, together form the foundations of a future world order that is free of nuclear weapons. That is the prize that seems as elusive as ever.
US announces resumption of nuclear testing
On 31st October, the United States, for the first time, voted against the annual resolution, at the First Committee of the UN General Assembly, commending the Comprehensive Nuclear-Test-Ban Treaty. The vote was 172 countries in favour, only the US voted in the negative.
This was preceded on the previous day by the announcement by US President Donald J. Trump to resume nuclear explosive test detonations. In his presser with reporters accompanying him on Air Force One, he elaborated that his order to resume nuclear explosive testing was in response to other countries carrying out nuclear tests deep underground.
The President named China, Russia and Pakistan and stated that, “They seem to all be nuclear testing. We have more nuclear weapons than anybody. We don’t do testing … But with others doing testing, I think it’s appropriate that we do also.” In his Truth Social post, he said, “That process will begin immediately.”
Both the President’s announcement and the US vote against the CTBT resolution came as a surprise to the international nuclear arms control community, even though in his first term he had alluded to resuming nuclear test detonations.
Another surprise is the continuing thundering silence from the many countries professing to be ardent supporters of the CTBT and the moratoria on nuclear testing declared by each of the five nuclear-weapon States. Likewise, relevant international nuclear organizations in Vienna charged with verification of multilateral nuclear arms control treaties, and the United Nations organization, have yet to speak out forcefully to defend the CTBT and the moratoria on nuclear test detonations.
It would not be an exaggeration to characterize the announcements from the US as unwelcome, that not only violate the US commitment to honour obligations under the CTBT as a signatory State and the nuclear testing moratorium mandated by Congress in 1992. In addition, the announcements go against the US’ commitments and obligations pursuant to the nuclear Non-Proliferation Treaty, of which the US is a depositary State with special responsibilities.
It might be recalled in this regard that the US Senate regrettably rejected ratification of the CTBT in October 1999, and no US president since has dared to put it up again for ratification.
Despite the recent developments noted here, for the time being the United States continues to observe the 1992 nuclear test moratorium. The National Nuclear Security Administration (NNSA) continues to maintain a readiness to detonate an underground nuclear test if required to ensure the safety and reliability of the US nuclear warhead stockpile or, if otherwise directed by the president, for policy reasons.
In the past, the NNSA has maintained a 24‐ to 36-month nuclear test readiness posture in accordance with Presidential Decision Directive (PDD) 15 (1993); however, the test readiness response time has evolved over the years. A complex nuclear test might take 36 months to field and conduct, while a “simpler” test might be possible in a 24‐month or shorter time interval.
Reportedly, while 33 pre-drilled vertical shafts exist at the Nevada National Security Site (NNSS) that potentially could be used for resumed nuclear tests, provided that the shafts are still usable and the equipment required to safely detonate nuclear devices underground is functional.
In practice, the NNSA plan is to sustain the nuclear warhead stockpile and to consolidate it to three-types of ballistic missile warheads and two air‐delivered systems (i.e. a “3+2” vision). Such a stockpile is postulated to yield a number of advantages such as being simpler to maintain and improving overall safety and security; employing interoperable nuclear explosive packages with adaptable non-nuclear components. And, to continue to rely on the Science-based Stockpile Stewardship Programme (SBSS).
Sub-critical Tests
Following the pronouncements by the US President, Chris Wright, the Secretary of the US Department of Energy (DoE), clarified on 2 November 2025, that the US will not be conducting any nuclear test detonations. Rather, under the Science-based Stockpile Stewardship Programme, the NNSA is continuing with its subcritical tests.
Subcritical experiments are designed to test the condition and reliability of nuclear warheads in the operational stockpile.
The subcritical hydrodynamic tests do not involve a nuclear explosion (or criticality), and are not prohibited under the CTBT, as these do not use fissile material, and cannot be independently verified being underground laboratory activities.
The US stockpile stewardship programme, at one level, involves the world’s most advanced supercomputers at the nuclear weapons labs to conduct large-scale digital simulations of nuclear weapons from “button to boom.”
The US Nevada National Nuclear Security Site conducts highly classified nuclear experiments to generate data that ensure that the simulations are accurate, they are all “subcritical” in that they simulate conditions inside a nuclear weapon without triggering a nuclear chain reaction. Subcritical experiments are designed to obtain information about the performance and safety of the US nuclear weapons stockpile in the absence of nuclear testing.
Subcritical (hydrodynamic) experiments involve chemical explosives to produce high pressures that are applied to plutonium (Pu) or other materials to study ageing effects – the oldest plutonium in US nuclear weapons now is 80 years old. A subcritical experiment may include plutonium but no critical mass is formed so that no self-sustaining nuclear chain reaction occurs. In this context, scientists capture high-quality radiographic images relevant to nuclear warhead safety.
These images are similar to X-ray images taken by a dentist but are more than a thousand times more powerful than a dental X-ray.
Hydrodynamic experiments also are carried out with surrogate materials (other heavy metals) instead of plutonium. As the material properties of surrogates differ from those of plutonium, surrogate experiments require extrapolation and interpretation; they complement rather than replace subcritical experiments involving plutonium.
The Lawrence Livermore Nuclear Laboratory (LLNL) “has carried out hundreds of hydrodynamic tests over the last six decades in support of the Stockpile Stewardship Programme’s goals in the absence of full-scale nuclear testing, which came to an end in 1992.”
According to the LLNL, the entire integrated system is to “compare the results of the hydrodynamic tests with simulations to provide more accurate assessments of the conditions that trigger a nuclear device’s primary—the mass of plutonium that initiates full detonation.” Such tests will continue as long as the US retains nuclear weapons.
Hydronuclear tests, on the other hand, involve a combination of high explosives, usually in a nuclear weapon configuration, and fissile material (enriched uranium and/or plutonium) whose quantity is reduced far below the amount required for a nuclear explosion. Such experiments are sometimes referred to as “zero-yield tests” although the energy released by fissions, while small, is not necessarily ‘true zero’.
These tests sometimes are referred to as “tickling the tail of the dragon”, as they involve fractional criticality or implosion of nuclear material but do not maintain a supercritical mass long enough for full nuclear yield and are prohibited under the CTBT.
It is assumed that China and Russia also have their separate subcritical testing programmes, but it is not known whether these are at the level of sophistication and complexity as of the US? Also, it is not known whether India, Israel, North Korea and Pakistan carry out subcritical hydronuclear and hydrodynamic tests?
Russian response to US announcements
Not to be left behind, on 5 November, Russian President Vladimir Putin instructed his officials to “submit agreed proposals on the potential start of preparations for nuclear weapons tests.” Russian Defence Minister Andrey Belousov, said it was advisable to “immediately begin preparations for full-scale nuclear tests.”
These announcements from Moscow also are deeply troubling, especially since the Russian Federation remains a depositary State for the NPT. In 2000, the Russian Duma ratified the CTBT, but late last year Russia “de-ratified” stating that it wanted to be on an equal plane as the US – both as non-ratifiers.
Breaking with the 1995 NPT Commitment
I must recall in this context of the CTBT that I was a member of the Canadian NPT Delegation in 1995, when the NPT was up for extension and preservation. At that time led by Canada, the Russian Federation and the United States, along with other countries, agreed to the indefinite extension of the NPT predicated on a formal binding Decision that included achieving the CTBT no later than 1996.
To date, according to UN Office of Disarmament Affairs, Disarmament Treaties Database, 187 States have signed the CTBT and 178 have ratified. But nine of the 44 named States remain to ratify the CTBT in order for it to enter into force and become operational with its 321 verification stations worldwide.
Were the United States and the Russian Federation to resume nuclear test detonations, this would amount to a clear breach of their commitments not only as signatories to the CTBT, but also of those given in May 1995 to the-then 173 non-nuclear-weapon States parties to the NPT to secure the indefinite (permanent) continuation in force of the NPT. As well as their obligations pursuant to Article VI of the NPT to achieve nuclear disarmament.
The NPT has been reaffirmed continuously by all NPT States as constituting the essential cornerstone of the global nuclear non-proliferation and nuclear disarmament architecture, along with cooperation in the peaceful uses of nuclear energy. Slow and unsteady progress towards nuclear disarmament continues to fuel discord among NPT States and is slowly eroding the integrity and authority of this treaty. Resumption of nuclear test detonations will only serve to further deepen and harden these fissures.
Unsteady Steps to Promote Entry-into-Force of the CTBT
Starting in October 1999 in Vienna, and since then there have been conferences in New York on the margins of the General Assembly, to promote the entry-into-force of the CTBT.
But over time and in light of the deteriorating international security situation and the erosion of the global architecture for nuclear arms control and disarmament, these conferences have regressed into performative talk shops and continue to fail to have any impact on the CTBT non-signatories (DPRK, India and Pakistan) to sign, and the non-ratifiers (China, Egypt, Iran, Israel, Russia and the USA) to ratify the treaty.
At this year’s Article XIV conference held at the UN in September, the participating States adopted fifteen ‘measures’ that as usual ‘encouraged’ and ‘called upon’ States “to take concrete and actionable steps towards early entry into force and universalization of the Treaty.” All hortatory and mundane with no timelines or enforcement.
CTBT: Is It a Flawed Treaty?
The objective of a comprehensive ban on nuclear testing originally had been truly comprehensive: non-proliferation and disarmament, but the CTBT lacks substantive link to nuclear disarmament.
As Rebecca Johnson of The Acronym Institute, who closely followed the CTBT negotiations, has astutely noted, throughout the treaty negotiations, the purpose of a ban on all forms of testing became progressively de-linked from the ultimate objective of the total elimination of nuclear weapons. In the final text, non-nuclear-weapon States were barely able to establish a relationship between the exhortations for nuclear disarmament in the preamble and the operative text of the CTBT.
As noted above, the CTBT even permits non-explosive forms of testing, which, with advances in technology, may today be used to refine nuclear weapons and to design new ones.
The CTBT does not require the closure of nuclear test sites, as a result nuclear test sites remain active but dormant in China, India, North Korea, Russia and the United States. To its credit, France is the only nuclear-weapon State to have verifiably decommissioned its nuclear test sites.
As a result of a complex formula adopted at the insistence of the nuclear-weapon States, the CTBT requires forty-four named States to sign and ratify the treaty to enter into force, and no time line is specified.
As noted above, signatory States, China, Egypt, Iran, Russia and the United States still need to ratify. But there is no pressure exerted on these NPT States in NPT meetings. And the same goes for non-signatories, DPRK, India and Pakistan, and for Israel which has signed but not ratified.
At this rate and given the collapsing nuclear arms control architecture, it seems that the CTBT will never enter into force, but hopefully the moratoria on nuclear testing could continue despite the recent developments noted here?
The Way Forward
Should nuclear explosive testing resume, it would not only kill the CTBT but also open the flood gates to a flurry of nuclear test detonations by nuclear-armed States. And, guarantee a fateful (and fatal) collapse, the third in a row, of the crucial NPT review conference (scheduled for April-May 2026) – and perhaps of the NPT itself!
For the CTBT Organization (CTBTO) in Vienna to continue to retain its credibility and authority, it must show visible leadership and build a strong coalition of States to defend the CTBT, preserve the moratoria on nuclear explosive tests, and demonstrate determined resolve to oppose any resumption of nuclear tests by any country whatsoever.
In this effort, it is essential that Japan, the only country to be the victim of two atomic bombings, rise to the occasion to support the CTBTO to defend the CTBT, and thus honour the ultimate sacrifices of the citizens of Hiroshima and Nagasaki who perished on 6th and 9th August 1945, respectively, as well as those who survived the atomic bombings – hibakusha. All other UN Member States share the same responsibility!
*Tariq Rauf is former Head of Verification and Security Policy at the International Atomic Energy Agency. These are his personal comments. [IDN-InDepthNews]
Image source: Discovery Alert