"The CTBT at 30"
Daryl G. Kimball, Executive Director, Arms Control Association
Remarks for Virtual Appearance for the Valdai Discussion Forum, September 10, 2026
The CTBT is one of the most successful and successful nuclear nonproliferation agreements in the history of the nuclear age. It brought an end to a dangerous, deadly era that involved more than 2,000 nuclear explosions.
Today marks the anniversary of the UN General Assembly's endorsement of the treaty by a wide 158-3 margin. As Madeleine K. Albright, the U.S. ambassador to UN at the time, said: ''Today nations of every size and outlook, from every continent, reflecting every culture and background, joined in support of a total ban on nuclear test explosions and other nuclear explosions of any size, in any place, at any time. This was a treaty sought by ordinary people everywhere, and today the power of that universal wish could not be denied.''
The treaty is the product of decades of global citizen campaigning, years of scientific research, and on-and-off negotiations. It is an amazing success story with many, many authors. Every signatory state can take some credit. I am grateful to all of those who advanced the cause and am proud to have played a part, along with many civil society leaders and millions of activists, in its realization over the years.
Today, the treaty has 188 signatures and near-universal support; no state is openly violating the treaty, which bans any and all nuclear explosions, which the N5 all understand to be any nuclear test that which produce a self-sustaining fission chain reaction.1
But today, the de facto global nuclear test moratorium and the CTBT are facing unprecedented new challenges.
Not only have nine key states failed to ratify the treaty, which has held up its formal entry into force, but there are new U.S. accusations that China and and Russia have engaged in very low-yield testing, and in response, President Donald Trump has threatened to resume U.S. nuclear testing for the first time since 1992.
The Russian Federation has taken the backward step of "de-ratifying" the treaty, and for now, progress toward securing the ratification of the nine CTBT hold-out states that must ratify to achieve entry into force have ground to a halt.
Here in the United States, my organization and others and many members of Congress are making the case that even if China might have conducted a nuclear test explosion in 202o, two nuclear wrong don't make a right. A resumption of U.S. nuclear testing would be a strategic disaster.
In fact, further testing by any major nuclear-armed state would technically and militarily unnecessary and would likely set off a chain reaction of nuclear testing by others and blow a massive hole in the fabric of the already tattered nonproliferation system.
Though the Trump administration did not take any active steps to resume nuclear explosive testing this year, I believe the White House is still actively exploring its options to do so.
In other words, the CTBT and the de facto global nuclear test moratorium cannot be taken for granted.
It is of course in the interest of all states to ensure that the remaining CTBT hold-out states promptly ratify the treaty to secure its entry into force, maintain universal compliance with "zero-yield" prohibition on nuclear explosions.
Perhaps even more urgently, however, it is vital that the NPT's Nuclear Five (N5) pursue new voluntary measures to build confidence that no state is conducting clandestine nuclear test explosions.
In the absence of the CTBT’s entry into force, which as we all know would allow for on-site inspections, there remains a risk that certain activities at these former nuclear testing sites that are prohibited -- very low yield nuclear experiments that produce a self-sustaining nuclear chain reaction -- might go undetected, or one state or another might make an accusation of cheating, as the United States has recently done.
Anticipating this situation, some 20 years ago at the third CTBT Article XIV Conference on Facilitating Entry Into Force in 2005, the Arms Control Association and other civil society experts recommended that the “nuclear weapon states should implement confidence-building … measures at their sites” to ensure they are not currently engaged in prohibited activities. At the time, the suggestion was dismissed by some states as premature.
Then in 2023, the head of the U.S. National Nuclear Security Administration, Jill Hruby proposed a commonsense variation on the same concept. She suggested the United States, Russia, and China could work together and with others "to develop a regime that would allow reciprocal observation with radiation detection equipment at each other’s subcritical experiments to allow confirmation that the experiment was consistent with the CTBT."2
At the 11th NPT Review Conference, the CTBTO's executive secretary, Dr. Robert Floyd, endorsed the pursuit of additional voluntary confidence building measures, before entry into force.
If our political leaders in Washington, Moscow, Beijing and elsewhere really care about the CTBT, in the coming months, the five nuclear-armed NPT states will agree to engage in professional, technical talks to devise voluntary confidence building measures to ensure any activities at former nuclear test sites fully comply with the CTBT's Article I prohibition on nuclear test explosions.
On the occasion of the 30th anniversary of the CTBT, heads of state and foreign ministers need to do more than issue stale statements of support for the treaty, key states must overcome their other differences and actively explore constructive ways to prevent the erosion and possibly the destruction of the CTBT and the NPT system.
NOTES
1 “Scope of the CTBT, Fact Sheet, US Department of State, Bureau of Arms Control, Verification and Compliance, n.d. http://www.state.gov/t/avc/rls/212166.htm
2 "Remarks by NNSA Administrator Jill Hruby at the Comprehensive Nuclear Test Ban Treaty: Science and Technology Conference 2023 (SNT2023)," June 19, 2023. See: https://www.energy.gov/nnsa/articles/remarks-nnsa-administrator-jill-hruby-ctbt-science-and-technology-conference-2023