The United Nations has issued a stark warning that the global norm against nuclear testing is fraying at a time of deep geopolitical division, spotlighting the refusal of key nuclear-weapon states to ratify the Comprehensive Nuclear-Test-Ban Treaty (CTBT). With the U.S., Russia, China and other nuclear powers still outside the treaty’s legal framework, UN officials say any resumption of testing could erode decades of restraint and trigger a new arms race. The message, delivered during a General Assembly event marking the International Day Against Nuclear Tests, underscores how the CTBT—adopted in 1996 but never formally in force—has become both a symbol and a casualty of today’s strategic rivalry.
The CTBT at a Crossroads: 30 Years After Adoption
Three decades following its signing, the CTBT is still one of the most important yet incomplete treaties of the nuclear age. As a means to stop all nuclear test explosions—whether underground, underwater, atmospheric or in outer space—the treaty seeks to inhibit the development of new nuclear powers and advancements in nuclear arsenals. However, for the treaty to enter into force, it must be ratified by all 44 “Annex 2” states, which include all the states which had nuclear capabilities when the treaty was signed. As at the end of August 2026, the CTBT has been signed by 188 states and ratified by 179 states, according to the numbers provided by UN and CTBTO at the General Assembly meeting. There are still nine Annex 2 states which have not ratified the CTBT yet: China, Egypt, India, Iran, Israel, North Korea, Pakistan, Russia, and the United States.
Of these, the United States, China, Iran, Egypt and Israel have signed but not ratified; India, Pakistan and North Korea have not signed at all; and Russia, which once ratified, revoked its ratification in 2023. This legal limbo means the CTBT operates in practice through a de facto moratorium rather than binding law. More than 2,000 nuclear tests were conducted globally between 1945 and the early 1990s, but fewer than 12 have occurred in the past three decades—a dramatic slowdown that UN and CTBTO officials now fear could be reversed.eeas.
“Deep Geopolitical Tension”: The UN’s Warning on a Divisive Moment
The timing of the UN’s intervention is deliberate. Disarmament chief Izumi Nakamitsu told the General Assembly that the world is in a period of
“deep geopolitical tension, growing division and diminishing trust,”
and warned that even contemplating a return to testing is dangerous. In her view, the norm against testing is not just a technical constraint but a political bulwark against escalation.
“Any resumption would erode decades of restraint, deepen mistrust and risk triggering reciprocal tests and an arms race. This must never become reality,”
Nakamitsu said, framing the issue as a test of whether major powers can still exercise self-restraint in a fracturing security environment.
Such comments highlight concerns about how the deterioration of the arms control regime through the collapse of treaties dealing with intermediate-range missiles and overflights may also lead to the testing regime. On 29 August, which was the International Day Against Nuclear Tests, the UN Secretary-General António Guterres reiterated this sentiment, asking all countries possessing nuclear arsenals to respect existing moratoriums and push forward towards the adoption of a comprehensive international treaty. “Nuclear testing undermines confidence,” said Guterres.
The Holdouts: Who Is Blocking the Treaty and Why
It is dependent on a small number of states whose strategy has kept the CTBT suspended legally for decades. The U.S., which signed the CTBT in 1996, did not ratify it citing issues of verification and its strategic need to test weapons to make sure that its arsenals were reliable. Recently published information indicates that threats or preparations for testing on the part of the U.S. connected with 2025 and 2026 have increased concern about the matter, although the U.S. government still has an official moratorium on testing. Russia, which ratified the treaty, has withdrawn from its ratification in 2023, which was seen as an indication of the country’s intention to conduct testing if needed. Combined with the rhetoric of the U.S., it has sparked concerns about a mutually reinforcing situation, when a testing on one side leads to reciprocal testing by the other side dragging others in. China, which is yet another country from Annex 2, has signed but not ratified the CTBT. It is accused of testing on the part of some U.S. officials, but China denies it. North Korea, which conducted a series of tests before announcing a pause, remains outside the treaty entirely.
Regional dynamics further complicate the picture. Iran’s mission to international organizations in Vienna has warned that Israel’s possession of nuclear weapons and its refusal to join the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) threaten the global non-proliferation regime. While the CTBT is distinct from the NPT, diplomats often link the two when discussing gaps in the architecture of nuclear restraint.
From Semipalatinsk to Tonga: The Human and Historical Stakes
The UN event also centered the human cost of nuclear testing, tying contemporary diplomacy to historical trauma. The International Day Against Nuclear Tests commemorates 29 August 1991, when Kazakhstan closed the Semipalatinsk test site, where 456 Soviet nuclear tests were conducted over decades. President Kassym-Jomart Tokayev used the 35th anniversary of that closure to call for renewed negotiations among nuclear powers and faster action to bring the CTBT into force.
“From the shadow of Semipalatinsk,” Tokayev urged nuclear powers to return to the negotiating table, framing the treaty as a moral imperative as much as a security one. Kazakhstan’s own experience—where generations suffered from radiation exposure, birth defects and long-term health consequences—has made it a leading voice for the CTBT’s completion.
At the UN, Tina Cordova of the Tularosa Basin Downwinders Consortium gave a harrowing account of life downwind from U.S. testing that began in 1945. She described five generations of her family exposed to radiation, with recurring cancers across the lineage.
“We were never warned before or after of the danger… We’re the people that became the collateral damage to the development and testing of nuclear devices and were left to deal with the consequences on our own,”
Cordova said, insisting that the human toll must not be forgotten in strategic calculations.
CTBTO’s Technical Warning: “Devastation from Nuclear Bad Luck”
Beyond the political and moral arguments, the CTBTO has been emphasizing the technical risks of a return to testing. Robert Floyd, the organization’s Executive Secretary, noted that Tonga’s recent ratification had brought the number of parties to 179, a milestone that nonetheless leaves the treaty short of entry into force. He contrasted the more than 2,000 tests conducted since 1945 with the fewer than 12 in the past three decades, underscoring how exceptional the current period of restraint has been.
Floyd’s warning was blunt: if testing resumes, the world should expect
“new technologically advanced nuclear arsenals, soaring risks of nuclear miscalculation, and ‘devastation from nuclear bad luck’.”
What the officials call “bad luck” in relation to the use of nuclear weapons refers to accidental situations and false launches resulting from increased complexity of the arsenal and heightened readiness levels. However, it must be noted that the global monitoring network set up by the CTBTO using the seismic, hydro-acoustic, infrasound, and radionuclide sensors can detect and identify the nuclear tests with great accuracy, but cannot stop the political will behind the test. Budget concerns have become yet another source of vulnerability. In its statement to Working Group B of the CTBT Preparatory Commission in late August 2026, the EU called for “urgent” ratifications despite the pressure of budget constraints.
Why the Stalemate Matters for the Broader Nuclear Order
The CTBT impasse is not an isolated issue; it reflects and reinforces wider fractures in the nuclear order. Gareth Evans, writing in late August 2026, described the outlook for nuclear arms control as
“desolate in all three of its dimensions – risk reduction, non-proliferation and outright elimination.”
In this view, the failure to bring the CTBT into force is both a symptom and a cause of the broader malaise.
In light of the fact that major powers do not bind themselves to a testing ban, the normative pressure to constrain their programs becomes difficult to exert on others. It also makes it difficult to solve the problems of proliferation in various regions around the world such as the Middle East and South Asia, where the nuclear program faces objections based on double standards in the nuclear regime. In this regard, the initiative of the European Union to seek ratification in addition to the warning regarding funding pressures clearly shows that even friendly nations find the regime vulnerable. On the other hand, CTBT is one of the few remaining pillars of the arms control regime of the Cold War era that enjoys wide international acceptance despite not being universal legally binding.
