"I want to thank the Arms Control Association … for being such effective advocates for sensible policies to stem the proliferation of weapons of mass destruction, and most importantly, reduce the risk of nuclear war."
– Senator Joe Biden
January 28, 2004
CTBT & Nuclear Testing

France Sued Over Past Nuclear Tests

A mushroom cloud rises above the Mururoa atoll, French Polynesia, after the explosion of a French atomic bomb in 1971. (Photo: Galerie Bilderwelt/Getty Images)France is facing a legal complaint filed Oct. 2 at the International Criminal Court (ICC) in The Hague over its nuclear testing in French Polynesia during almost four decades, ending in 1996. Oscar Temaru, a former president of French Polynesia and now opposition figure, accused France of crimes against humanity for the almost 200 nuclear tests France conducted on the Pacific atolls of Mururoa and Fangataufa. The action seeks “to hold all the living French presidents accountable,” he said. After long resisting such action, France in 2010 established a compensation program for military veterans and civilians whose cancer could be attributed to the nuclear tests, but few have received benefits under restrictive rules. France’s overseas minister, Annick Girardin, called the lawsuit an abuse of the international court for domestic political purposes. It is uncertain whether the ICC will agree to proceed with the case.—TERRY ATLAS

France Sued Over Past Nuclear Tests

MEDIA ADVISORY: Head of CTBTO Describes Inspection Option for North Korea Nuclear Test Site



New Analysis by CTBTO Executive Secretary Lassina Zerbo Published in Arms Control Today

For Immediate Release: Oct. 18, 2018

Media Contacts: Daryl G. Kimball, publisher, Arms Control Today, 202-463-8270 ext. 107; Kirstie Hansen, CTBTO Public Information Officer in Vienna, [email protected]

(Washington, D.C.)—Earlier this year, North Korea committed to closing its nuclear test site and invited journalists to view the destruction of test tunnels at its main nuclear test site.

As Dr. Lassina Zerbo writes in a new article in the journal Arms Control Today, “although the declared closure is welcome, those present lacked the skills and necessary specialized equipment to assess the activities that took place.”

The U.S. State Department issued a statement Oct. 7 indicating that North Korean leader Kim Jong Un “invited inspectors to visit the Punggye-ri nuclear test site to confirm that it has been irreversibly dismantled.” To date, it is not clear who would inspect the site and under what terms.

“The CTBTO and its technological tools,” Zerbo writes, “are uniquely placed to provide adequate verification and to monitor an end to nuclear tests in North Korea.”

Zerbo, who is serving in his second term as the Executive Secretary of the CTBTO, describes in detail the technologies the CTBTO can provide to verify the closure of a nuclear test site, and, he explains the value of North Korean signature and ratification of the 1996 Comprehensive Nuclear-Test-Ban Treaty (CTBT) for the denuclearization process.

“The path to the verifiable denuclearization of the Korean peninsula runs through the CTBT,” Zerbo writes. The CTBT has been signed by 184 states and ratified by 167. North Korea is not yet a signatory.

A large group of foreign ministers issued a joint statement Sept. 27 organized by Japan, Australia, Canada, Finland, Germany, and the Netherlands urging North Korea “to sign and ratify the CTBT as a matter of priority.”

“It is vital not to miss this opportunity to demonstrate to the world the value of the treaty and the efficacy of one of the most sophisticated and far-reaching verification regimes ever devised,” Zerbo says in the article.

The Nuclear Test Ban and the Verifiable Denuclearization of the Korean Peninsula” by Lassina Zerbo will appear in the November 2018 issue of Arms Control Today. It is available in advance online here


New Analysis by CTBTO Executive Secretary Lassina Zerbo Published in Arms Control Today

Country Resources:

CTBT Grows Amid Calls on N. Korea to Join

October 2018
By Shervin Taheran

The Comprehensive Test Ban Treaty (CTBT) has gained some renewed attention as nations called on North Korea to join the treaty as a way to demonstrate its sincerity in declaring an end to its nuclear testing.

CTBTO Executive Secretary Lassina Zerbo (2nd from right) looks on as the prime minister of Tuvalu, Enele Sopoaga, signs the Comprehensive Test Ban Treaty on September 25.  With the addition of Tuvalu, the number of signatory states grew to 184. Thailand became the 167th country to ratify the CTBT. (Photo: CTBTO)Meanwhile, Thailand became the 167th country to ratify the CTBT. With the Sept. 25 signature by the island nation of Tuvalu, the number of signatories was brought to 184. But the treaty will not enter into force until it is ratified by the eight remaining nations listed in its Annex 2: China, Egypt, India, Iran, Israel, Pakistan, North Korea, and the United States.

At a ministerial-level meeting of the “Friends of the CTBT” states Sept. 27, the foreign ministers of Australia and Japan, who co-chaired the meeting, and of Belgium, Finland, Iraq, Japan, and the Netherlands called on North Korea to ratify the CTBT.

The meeting reinforced a message sent to North Korea in June by the foreign ministers of Belgium and Iraq urging a “legally binding and irreversible end” to its nuclear testing, such as through the signature and ratification of the CTBT, as part of a denuclearization agreement. Belgium and Iraq are co-presidents of the 2017 Article XIV Conference on Facilitating the Entry Into Force of the CTBT and will continue in this role until the next Article XIV conference in 2019.

EU foreign affairs chief Federica Mogherini reaffirmed this sentiment in remarks at the meeting, urging North Korea to join the CTBT “without delay.” She noted that verifying the closure of the North Korean nuclear test site “could benefit” from the technical assistance of Comprehensive Test Ban Treaty Organization (CTBTO).

There has not been much public discussion about what the technical verification of the dismantlement of North Korea’s nuclear test site would look like, and questions remain about the roles of the CTBTO and the International Atomic Energy Agency (IAEA) in such a process. At a Sept. 6 UN event marking the International Day Against Nuclear Tests, CTBTO Executive Secretary Lassina Zerbo said that the organization is ready, if called upon, “to contribute to the process of verifiable denuclearization.”

Miroslav Lajčák, president of the UN General Assembly and Slovakia’s foreign minister, at the Sept. 6 event noted that North Korea’s decisions to suspend nuclear and missile tests were positive steps. Still, he said that signing and ratifying the CTBT “would lead to progress on the Korean peninsula.”

Thailand’s ratification is the last for a member of the Association of Southeast Asian Nations (ASEAN) “thereby reaffirming ASEAN’s long term goal of making the region of Southeast Asia a nuclear-weapon-free zone,” said Virasakdi Futrakul, Thailand’s deputy foreign minister.

Thailand becomes 167th country to ratify the treaty.

ACA Board Chair on Pathways to a Nuclear Weapon Free World



Pathways to a Nuclear Weapon Free World

Remarks by Thomas Countryman
Chairman of the Arms Control Association
to the International Symposium for Peace 
Nagasaki, Japan
July 28, 2018


Panelists discuss working toward sustainable peace at the International Symposium for Peace “The Road to Nuclear Weapons Abolition” held on July 28 in Nagasaki. (Photo: Kengo Hiyoshi/Asahi Shimbun) Let me thank the organizers of today’s conference for bringing me again to Japan. In my current focus outside the government of the United States, continuing to push for real progress on nonproliferation and arms control measures, it's always a special pleasure to come to Japan. The Japanese role in leading the international diplomatic challenge to create the highest standards in arms control and nonproliferation is unparalleled. Not only as a partner of the United States but in its own leadership role, Japan has done much to create the modern nonproliferation regime that has greatly reduced but not yet eliminated the threat that weapons of mass destruction pose to all of us.

It is especially moving to be here in Nagasaki. Visiting the memorial yesterday, a sacred place, brought back to me what President Abraham Lincoln said at the site of the bloodiest battle America ever witnessed: that those who have fallen on this site “have consecrated it far above our poor power to add or detract”. I sensed on this spot what no book can convey: the enormous challenge and the risk that humanity continues to face in the presence of 15,000 nuclear weapons in this world. Here I want to commend the very special role the hibakusha have played in preserving vital lessons for the memory of humanity. For 70 years, they have spread the simple truth that a human being is not just a statistic. They will touch future generations long after their own has passed from this world. I wish that every American and every world leader would have the opportunity to visit Hiroshima and Nagasaki as I have.

Current Challenges

It is much easier to talk about the challenges to nuclear disarmament than it is to describe a simple path to a world free of nuclear weapons. So let me dwell first on the current challenges that we face.

First, the two major nuclear powers, the United States and the Russian Federation, have passed a turning point in their nuclear doctrines and nuclear arsenals. After about 40 years of a steady decrease in the size and diversity of their nuclear arsenals and the mission that each assigned to their nuclear weapons, both Washington and Moscow have turned a corner towards expanding the size and variety of arsenals and the circumstances for their use.

U.S. 2018 Nuclear Posture Review

The U.S. administration’s Nuclear Posture Review from this February is not a radical change from the previous nuclear posture but it is a significant change in direction. In calling for the development of new low-yield nuclear weapons, the United States is thinking more actively and – in my view - making more thinkable the use of low-yield nuclear weapons in the context of a conventional conflict. As so many have pointed out, there is no such thing as a limited nuclear war once that threshold has been crossed. “A nuclear weapon is a nuclear weapon," George Shultz, who served as President Ronald Reagan's top diplomat, told the Senate Armed Services Committee in January. "You use a small one, then you go to a bigger one. I think nuclear weapons are nuclear weapons and we need to draw the line there."

Secondly, the Nuclear Posture Review describes with more specificity than before circumstances under which the United States would consider the use of nuclear weapons to encompass not only first use by an opponent but also a response to a devastating attack by cyber or other means. Just two years ago, the Obama administration considered carefully the possibility of proclaiming a no-first-use doctrine for U.S. nuclear weapons. That U.S. policy has now shifted towards a broader definition of possible first use is of deep concern to me.

Finally, I am most disappointed in the Nuclear Posture Review in that it effectively renounces the traditional leadership that the U.S has exercised on non-proliferation and arms control issues. It makes no mention of America’s binding legal obligation under Article VI of the Nuclear Nonproliferation Treaty to pursue a reduction in arsenals. It makes no new proposals for how the U.S. will move forward in negotiations with Russia and others. And it defers any meaningful action until security conditions in the world have improved. This retreat from global leadership, whether in arms control, in climate policy or in free trade agreements is unworthy of a nation that claims to be a superpower.


As concerned as I am about the direction of U.S. policy, I am even more concerned about the continuing development by Russia of new weapons and new delivery methods. Russia seems driven by an exaggerated fear, in fact, a paranoia, about the future capabilities of U.S. missile defense. I call these fears exaggerated because I believe that missile defense can never provide an impenetrable shield. Russia is building not only new generations of ICBMs but even more dangerous weapons systems that seem to step out of the pages of a science fiction comic book, including a nuclear torpedo of unlimited range and a nuclear-powered cruise missile. Russia seems intent on probing the boundaries of existing arms control agreements, particularly the Intermediate-Range Nuclear Forces Treaty which laid the basis for the next 25 years of successful arms limitations. Even more than the uninformed statements by the U.S. president, the rhetoric of the Russian president - increasingly defining Russia’s national power as a function of its nuclear arsenal - erodes both the prospect of future arms control and the moral taboo against initiating the use of nuclear weapons. The 2010 New Strategic Arms Reduction Treaty is due to expire in 2021 and although President Putin has raised the prospect of extending the treaty, President Trump has so far rebuffed such proposals.

Joint Comprehensive Program Of Action

In the shorter term, I am especially concerned about the U.S. decision to withdraw from, that is to violate, the Joint Comprehensive Program of Action with Iran. This agreement is unprecedented, both in its inspection and verification requirements, and it prevented the risk of a tenth state breaking into the nuclear weapons club. I do not believe that Iranian development of a nuclear weapon is imminent but I am deeply concerned about the follow-on effects of this decision, that is the undermining of U.S. credibility and commitment to any agreement, the creation of a serious dispute between the U.S. and its best allies in Europe and Asia, the erosion of the international rules-based order and a resurgent radicalism in Iran.

North Korea

I am less pessimistic but still deeply concerned about North Korea’s nuclear weapons program. President Trump did the right thing, trading in violent rhetoric for an opportunity for dialogue. There are dozens of reasons to distrust North Korea’s approach to negotiations and to doubt the capability of the Trump administration to negotiate a meaningful, verifiable denuclearization of North Korea. But the pursuit of negotiation is far preferable to simply sleepwalking towards war, as we seemed to be doing a year ago.

Nuclear Non-proliferation Treaty (NPT)

The nuclear Nonproliferation Treaty remains central to our shared global ambition to prevent the development of new nuclear weapons and to reduce existing arsenals. On the surface, the deliberations at NPT conferences often seem utterly divorced from the real world. In fact, all the concerns I’ve just listed have a real effect on the degree of consensus you can reach among NPT parties and on the commitment that other parties show to the treaty.

For the 2020 Review Conference, I can foresee the worst but I am determined to work for the best. The RevCon can easily be upset either by the U.S. and Russia sniping at each other or by the continued inability of the states in the Middle East to sit down together and begin the process of discussing a nuclear-weapon-free-zone in the Middle East. But the most severe threat to the unity of states-parties is the growing frustration of non-nuclear weapon states with the pace of nuclear disarmament. Seeing no new U.S.-Russian agreements since 2010 and the new threatening developments in Washington and Moscow that I’ve already described, the majority of the world’s non-nuclear weapon states have made clear that they will demand more urgent progress in 2020.

Moving Towards a Nuclear Weapon Free World

So what can we do to move towards a world free from nuclear weapons?

Near-Term Steps

There are a number of steps that the United States and Russia could take right now that would change the current trajectory. First and most simply, to hear President Trump and President Putin repeat what Mikhail Gorbachev and Ronald Reagan said in 1985 - that a nuclear war can never be won and must never be fought - would be of value, would provide some reassurance that these two leaders understand their responsibilities to humanity. Secondly, the United States and Russia need to extend New START. Third, they need to make a political decision to work harder on resolving the dispute about compliance with the Intermediate Nuclear Forces treaty. And fourth there needs to be a more regular dialogue between Moscow and Washington on both the military and political level, to pursue risk reduction measures that would prevent a conventional conflict from escalating to a nuclear one and to explore other steps that would allow each to maintain security at a lower level of armament. Finally, the United States should reassert the leadership it showed after 2010 when it led an intensive dialogue among the P5 nuclear-weapon states to give the world greater transparency, to reduce nuclear risks, and to lay the groundwork for future multilateral arms control.

It’s not easy to get either Donald Trump or Vladimir Putin to do something that reminds them of Mikhail Gorbachev or Barack Obama. In fact, it’s not easy to get them to do something unless you can convince them that it was their own brilliant idea. But it is an obligation of the rest of the world to continue to press for this. I know from my own experience with bilateral diplomacy that meetings with either Russian or American leaders always have an agenda filled with urgent items and that concerns about long-term items such as arms control simply fall out of the conversation. It is crucial that not only Japanese leaders but all world leaders press both Presidents to take serious action.

Treaty on the Prohibition of Nuclear Weapons

Beyond Moscow and Washington, what can non-nuclear weapon states do for themselves to move us towards a nuclear-weapon-free world? Many non-nuclear weapon states have sought to answer that question by negotiating a new treaty banning nuclear weapons, adopted last July.

The drafting of the Treaty on the Prohibition of Nuclear Weapons last year was historic. Some would like to see it as simply an expression of frustration on the part of the non-nuclear weapon states. It’s a lot more than that. It is a strong moral and ethical statement. And more than that, it is something tangible, something that can be touched by the hibakusha and the citizens of Nagasaki and Hiroshima. It is a statement of reality that the risk of nuclear war is not born only by the nuclear-weapon states but by the entire world. And it is intended to serve as an impulse for further action globally on nuclear disarmament. I’m well aware of its limitations. The TPNW will not by itself immediately eliminate any nuclear weapons. And it does not provide a pathway for Washington and Moscow to overcome their current impasse.

I don’t see the discussion between advocates and skeptics of the TPNW as being an argument about practicalities or about whether this treaty can work. It is - or it should be - a respectful discussion about deterrence. Nations that face no immediate military threat tend to underestimate the importance that military alliances and military deterrence play for those states that do face actual military threats. Similarly, those states whether in Europe or in Asia that feel reassurance under the nuclear umbrella of the United States tend not to appreciate how strongly concerned other states are about the disastrous humanitarian effects that a nuclear war would cause.

What is needed now is a multi-sided discussion on a topic that is easy to define and extremely difficult to resolve: how to guarantee the security of the world and of each nation without resort to nuclear deterrence. This is a discussion that has to bring together not only the idealists and social activists who helped to bring about the TPNW but also the security experts and military leaders who have the responsibility of providing for their nations’ security. It has to bring together not only nuclear-weapon states but those who are allies of nuclear-weapon states and those who feel themselves to be far from any military threat. Given my own experience with the ineffectiveness of the United Nations as a place to discuss such difficult issues, I think it has to start smaller than a conference of 190 countries.

UN Secretary-General’s Disarmament Agenda

Washington and Moscow are not going to lead this discussion. What can the rest of the world do? The UN Secretary General has laid out a comprehensive blueprint on what needs to be done on disarmament issues to provide genuine security for our citizens. I love the document. I’d like to focus in particular on what he says about nuclear disarmament.

He calls on the United States and Russia to resolve INF compliance concerns, extend New START and pursue additional reductions. He encourages all states to sign and ratify the Comprehensive Test Ban Treaty, to negotiate a fissile material cutoff treaty, establish a zone free of nuclear weapons in the Middle East, pursue nuclear risk reduction measures, and develop nuclear disarmament verification standards and techniques. He warned that the international community is moving backward on disarmament. “Let us all work together to bring new urgency to achieve the universal goal of a nuclear-weapon-free world,” he said while unveiling his agenda at the University of Geneva in late May.

So how do we take forward an idea on which not only everyone in this room but most of the world is united upon?

Joint Enterprise

Now is the time to convene a high-level summit approach to help overcome the impasse on nuclear disarmament. Leaders from a core group of states can invite their counterparts - 20 to 30 heads of states of nuclear weapon and non-nuclear weapon countries - to join a one or two day summit on steps to achieve a world free of nuclear weapons. This could be a starting point for ongoing regular disarmament discussions at the expert and ministerial level. As the former foreign minister Kishida argued, this dialogue must be based both on a clear understanding of the devastating impact of nuclear weapon use and an objective assessment of the security concerns of states.

This is not a new idea. Four of the best American thinkers on such issues - George Shultz, William Perry, Henry Kissinger, Sam Nunn - have been arguing for several years for a Joint Enterprise, a new multilateral effort that would take concrete, practical steps to create the conditions that would make possible genuine nuclear disarmament. As outlined by the “four horsemen,” a Joint Enterprise summit would be supplemented by a joint communique from all participating states and national commitments to work towards disarmament. Unfortunately, the leadership of such an effort will not come from either Washington or Moscow. When the long-time ‘leader of the free world’ is deliberately stepping away from leadership, the other democratic nations of the world must take up the challenge. It’s up to Japan, to Germany, to Canada, to other nations that still believe in multilateralism to get this effort started.

Discussion of the conditions that would help achieve a nuclear weapons-free world must become as common among world leaders as discussions about tariffs or immigration. The constant raising of this topic is the responsibility of Presidents and Prime Ministers, and it is the duty of citizens of all nations to remind their leaders of this responsibility.

It is written in Pirkei Avot, a well-known Jewish text, that “you are not obligated to complete the work, but neither are you free to desist from it.” Here in Nagasaki, we say again that all of us – elected leaders, civil society organizations, and ordinary citizens – “we will not desist from this duty.”

Thank you and God bless you!




Remarks by Thomas Countryman to the International Symposium for Peace in Nagasaki, Japan

North Korea Urged to Sign CTBT

North Korean leader Kim Jong Un’s statement announcing the closing of the Punggye-ri nuclear test site has led to calls for Pyongyang to sign and ratify the 1996 Comprehensive Test Ban Treaty (CTBT). Federica Mogherini, the EU foreign policy chief, noted in a statement that Kim’s announcement was a positive “long-sought-after” step toward several disarmament commitments and the ratification of the CTBT. Lassina Zerbo, the Comprehensive Test Ban Treaty Organization (CTBTO) executive secretary, called for North Korea to consider signing and ratifying the CTBT, noting that a legally binding treaty is the only way to “solidify the moratorium on nuclear testing.” The CTBTO “stands ready to assist,” he said in an statement April 21, and some experts have proposed having the body engage in confidence-building site visits to Punggye-ri. —SHERVIN TAHERAN

North Korea Urged to Sign CTBT

G-7 Ministers Snub Ban Treaty

Foreign ministers from the Group of Seven nations said that they regard the nuclear Nonproliferation Treaty (NPT) as “the essential cornerstone” of the nonproliferation regime aG-7 “family photo” taken at a reception at the Royal Ontario Museum in Toronto April 22. They are (from left): Japanese Foreign Minister Taro Kono, British Foreign Secretary Boris Johnson, French Foreign Affairs Minister Jean-Yves Le Drian, Canadian Minister of Foreign Affairs Chrystia Freeland, U.S. Deputy Secretary of State John Sullivan, German Foreign Minister Heiko Maas, Italian Minister of Foreign Affairs Angelino Alfano, and European Union foreign policy chief Federica Mogherini. (Photo: LARS HAGBERG/AFP/Getty Images)nd “a foundation for the pursuit of nuclear disarmament.” Without saying so explicitly, the language reflects their continuing rejection of the new Treaty on the Prohibition of Nuclear Weapons, even as some countries say nuclear-armed countries have not done enough under the treaty’s disarmament obligations. “While recognizing the constraints of the current international security environment, we remain strongly committed to the goal of ultimately achieving a world without nuclear weapons, to be pursued using practical and concrete steps in accordance with the NPT's emphasis on easing tension and strengthening trust among states,” according to the group statement following their April 23 meeting in Toronto.

The G-7 ministers did express support for the Comprehensive Test Ban Treaty (CTBT), which the United States signed in 1996 but has not ratified due to Republican opposition, and for “our commitments to promote the International Monitoring System” established through the CTBT to detect underground nuclear tests.—TERRY ATLAS

G-7 Ministers Snub Ban Treaty

Revitalizing Diplomatic Efforts to Advance CTBT Entry Into Force


April 25, 2018
By Daryl G. Kimball
Executive Director, Arms Control Association

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More than two decades after the opening for signature of the Comprehensive Test Ban Treaty (CTBT), the treaty has near universal support and has established a global norm against nuclear test explosions. The nuclear testing taboo impedes the development of new and more advanced nuclear warhead designs, which helps prevent dangerous nuclear competition, and maintain international security.

Although the CTBT has created a norm against testing and a robust technical organization responsible for the operation and maintenance of a highly sensitive global nuclear test monitoring system, the treaty has not entered into force due to the failure of eight key states, including the United States and China, to ratify.

The CTBT is and will continue to be an essential pillar in the global nuclear nonproliferation and disarmament enterprise. Moving closer to the goal of the CTBT’s formal entry into force is the task of every CTBT state party, every nuclear Nonproliferation Treaty (NPT) state-party, every state that supports the new Treaty on the Prohibition of Nuclear Weapons, and any other state that considers itself a “responsible” nuclear actor.

But in order to realize the full potential of the treaty and to close the door on testing, friends of the CTBT will need to rejuvenate and update their efforts to achieve its entry into force and reinforce the taboo against nuclear testing.

For the first five decades of the nuclear age, nuclear weapon test explosions were the most visible symbol of the dangers of nuclear weapons, nuclear arms racing, and the omnipresent danger of nuclear war—or as President John F. Kennedy described it, the nuclear “Sword of Damocles” that hangs over every man, women and child on the planet.

The 1996 Comprehensive Test Ban Treaty has brought the era of frequent nuclear testing to an end and has established a strong norm against any kind of nuclear test explosion. The treaty has near-universal support with 183 signatories, including the five original nuclear testing states.

The Comprehensive Test Ban Treaty Organization (CTBTO), with headquarters in Vienna, is operating on a 24/7 basis to collect and analyze data in real time from a global network of nuclear test monitoring stations. The CTBTO’s International Monitoring System, which is nearly complete and is operating on a 24/7 basis, serves as a strong deterrent against any state that might consider conducting a clandestine nuclear test explosion.

However, the door to nuclear testing remains open as the treaty has not entered into force due to the treaty’s onerous Article XIV provisions, which require that 44 specific states sign and ratify. Currently there are eight “hold out” states—China, the Democratic People’s Republic of Korea (DPRK), Egypt, India, Iran, Israel, Pakistan, and the United States—which have failed to ratify.1

The non-testing norm cannot be taken for granted and, over time, it must be actively renewed and reinforced. In order to realize the full potential of the treaty, to close the door on further nuclear testing, and to reinforce the nonproliferation regime, states must need to rejuvenate their efforts to achieve the entry into force of the CTBT.

Unfortunately, the United States, which was leading proponent for the CTBT during the 1990s is now lagging behind. Without explanation or a high-level review or consultation with allies, the Donald Trump administration announced in February 2018 that it will not seek Senate approval for U.S. ratification of the CTBT.

In response, other hold-out states, particularly China, need to lead the way by signing and/or ratifying the treaty, and all signatory states should reaffirm their support for a permanent, verifiable end to nuclear test explosions by achieving entry into force of the CTBT, including by means of a joint heads of state declaration in the run-up to the 2020 NPT Review Conference.

Supporters of the global norm against nuclear testing and CTBT entry into force should also explore how North Korea’s pledge to close its only known nuclear test site at Punggye-ri beginning April 21 and suspend nuclear testing for the foreseeable future can be solidified into a legally-binding, more verifiable commitment by securing Pyongyang’s signature and ratification of the CTBT through the ongoing diplomatic negotiations with South Korea and the United States on the denuclearization and the establishment of a lasting peace regime on the Korean peninsula.

Regional adherence to the CTBT in the Middle East—and the creation of a regional nuclear weapons test free zone—should also be pursued as a new approach toward building the foundation for a WMD-free zone in the region, which is a long-standing but unfulfilled goal of every state party to the NPT.

The Role of the Comprehensive Test Ban in Nonproliferation and Disarmament

Since 1945, nuclear testing has been used to develop new, more advanced nuclear-warhead designs and to demonstrate nuclear-weapon capabilities. Nuclear testing has propelled the global nuclear-arms competition and undermined global peace and security. In aggregate, at least eight states (United States, Soviet Union, United Kingdom, France, China, India, Pakistan, and North Korea) have conducted more than 2,0562 nuclear test explosions, with U.S. tests accounting for nearly half that total.

For nearly as long, a global, verifiable ban on nuclear test explosions has been a goal for international nuclear risk reduction, nonproliferation, and disarmament. Without the ability to conduct nuclear explosive tests, a country cannot confidently develop more advanced types of nuclear warheads.

Kazakh citizens gather to demand an end to nuclear testing at the Soviet nuclear test site near Semipalatinsk in August 1989.   (UN Photo/MB)


A global nuclear test ban was first formally proposed in 1954 by Indian Prime Minister Jawaharlal Nehru as a step toward ending the nuclear arms race and preventing proliferation—and to prevent the significant health and environmental damage produced by atmospheric nuclear-test explosions.

In the negotiations for the 1968 Treaty on the Non-proliferation of Nuclear Weapons (NPT), the CTBT was widely recognized as a critical part of the nuclear-weapon states’ obligation to meet their NPT Article VI commitment to “effective measures relating to cessation of the nuclear arms race at an early date and to nuclear disarmament.”3 The preamble of the NPT specifically cites the goal of “the discontinuance of all test explosions of nuclear weapons for all time and to continue negotiations to this end.”4

Not until the end of the Cold War would the conditions to secure the CTBT finally became more favorable. An important catalyst was the pressure of a popular protest movement in Kazakhstan, which successfully pressed the Soviet government in Moscow to close the Semipalatinsk test site and announce a unilateral nuclear test moratorium in October 1991. Late the following year, the U.S. Congress approved legislation mandating a nine-month U.S. moratorium with conditions on the resumption of nuclear testing. The next year, President Bill Clinton decided to extend the U.S. test moratorium and pursue negotiations on a CTBT at the Conference on Disarmament.

The push for the comprehensive test ban became a key variable in the negotiations between the “nuclear-haves” and the “nuclear-have-not states” at the pivotal 1995 NPT Review and Extension Conference. Support from the NPT’s five recognized nuclear-weapon states for the CTBT gave non-nuclear-weapon states leverage at the NPT conference and contributed to the decision to extend the treaty and adopt a strong “program of action” for disarmament, including the conclusion of CTBT negotiations by the end of 1996.5

Following two years of intense multilateral negotiations, the United Nations General Assembly overcame an attempt by India to block the treaty when it adopted a resolution endorsing the CTBT on September 10, 1996, by a vote of 158-3. Two weeks later, on September 24, the treaty was opened for signature. U.S. president Bill Clinton became the first signatory.

As the Executive Secretary of the Comprehensive Test Ban Treaty Organization, Lassina Zerbo, and Russian Deputy Foreign Minister, Sergei Ryabkov, wrote in an April 2017 essay, Article I of the CTBT prohibits “’any nuclear weapon test explosion or any other nuclear explosion’ anywhere on Earth, whatever the yield.”6 This provision of the treaty is recognized by all of the major negotiating parties to mean that supercritical hydronuclear tests (which produce a self-sustaining fission chain reaction) are banned, but subcritical hydrodynamic experiments (which do not produce a self-sustaining fission chain reaction) are permitted.7

In 1997, the Comprehensive Test Ban Treaty Organization was formally established to work with state parties to build and operate a robust International Monitoring System (IMS) and International Data Center (IDC). Today, the IMS is nearly 90 percent complete, the IDC is fully functional, and the CTBTO is a mature, highly professional, and fully operational organization that is collecting and analyzing information on a continuous round-the-clock basis for the purpose of detecting and deterring clandestine nuclear-test explosions and to provide the technical basis for international responses to noncompliance.

Once the treaty formally enters into force, the verification system will also include the option for short-notice on-site inspections to investigate suspicious events. Information from states’ national intelligence networks, which are more sensitive in some geographic regions, can be taken into account.

In anticipation of the fact that the treaty’s onerous Article XIV entry into force provisions would delay entry into force, Canadian negotiators insisted on a provision in Article XIV that allows for conferences of states-parties to meet every two years to develop strategies and seek ways to accelerate the process toward securing the necessary 44 ratifications. Beginning with the first such conference in 1999, there have been ten such meetings, which have, unfortunately become pro forma affairs that primarily allow states which have signed and/or ratified to reiterate their support, exhort hold-out states to take action, and to develop a modest joint diplomatic outreach plan.

The Nuclear Testing Taboo

Since the CTBT opened for signature it has established a powerful standard of “responsible” behavior. Nations that conduct nuclear tests are outside the international mainstream and will bear the consequences of global isolation. Only one country—North Korea—has conducted nuclear test explosions in this century.

Even India, which strongly opposed the CTBT during and after the conclusion of the negotiations in 1996, has declared a moratorium on nuclear testing following its May 1998 series of nuclear tests.8 Pakistan, which responded with its own nuclear tests weeks later, has also since observed a testing moratorium and declared it would not be the first state in the region to resume nuclear testing.9

International support for the CTBT has been reaffirmed over the years through multiple UN General Assembly resolutions and UN Security Council (UNSC) resolutions. UNSC Resolution 1887 (2009) calls upon all states “to refrain from conducting a nuclear test explosion and to sign and ratify the Comprehensive Nuclear Test-Ban Treaty, thereby bringing the treaty into force at an early date.”10

On the occasion of the twentieth anniversary of the opening for signature of the CTBT in Sept. 2016, the UNSC adopted the first-ever, CTBT-specific resolution (UNSCR 2310), which reaffirms the global norm against nuclear-weapon-test explosions, calls on the eight remaining states that must ratify for entry force to do so, and urges all states to provide their full financial and technical support to the CTBTO. The resolution was formally co-sponsored by forty-two states, including Israel.11

The new UNSC test-ban resolution also formally recognizes the important September 15, 2016, statement12 from the permanent five members of the council expressing the view that any nuclear test explosion would “defeat the object or purpose of the treaty.” The statement gives public expression to the existing legal obligation of all CTBT signatories not to test a nuclear weapon, even before the treaty enters into force.13

The Treaty on the Prohibition of Nuclear Weapons (TPNW) negotiated, which was opened for signature in 2017, further reinforces the CTBT and the non-testing norm. Under the TPNW, states parties may not “test” nuclear weapons or any other nuclear explosive devices.

Nonproliferation and Disarmament Benefits

A global ban on nuclear explosions has been a central element of the nuclear nonproliferation and disarmament enterprise because an effective, comprehensive, verifiable test ban directly constrains the ability of all parties to develop more-advanced nuclear weapons.

As noted in the preamble of the 1996 treaty: “the cessation of all nuclear weapon test explosions and all other nuclear explosions, by constraining the development and qualitative improvement of nuclear weapons and ending the development of advanced new types of nuclear weapons, constitutes an effective measure of nuclear disarmament and non-proliferation in all its aspects.”14

U.S. Secretary of State John Kerry and other diplomats vote to adopt the resolution in support of the Comprehensive Test Ban Treaty during a UN Security Council meeting September 23, 2016. (Photo: Astrid Riecken/CTBTO)


Technically, a state might have some degree of confidence that a simple, relatively cumbersome fission device would work without testing, as the United States did with the Hiroshima bomb in 1945. Today, a country with no or little nuclear-weapons design and nuclear test explosion experience might be able to acquire an ambiguous nuclear deterrent without nuclear-explosive testing, but under the CTBT it could not use a nuclear test to demonstrate that capability, as India did with its first nuclear-test explosion in 1974.

However, the test ban constrains nuclear weapons development by states with little or no nuclear testing experience by blocking the progression from simple fission designs to “boosted” fission designs to two-stage thermonuclear designs with better yield-to-weight ratios.

How far along the developmental ladder a proliferator could go without nuclear explosive testing is not exactly clear, but states intent on acquiring and deploying modern, two-stage thermonuclear weapons compact and light enough to deliver on long-range ballistic missiles would certainly not have confidence in their performance without multiple, multi-kiloton nuclear-test explosions, which would very likely be detected by the CTBTO’s International Monitoring System and national technical means of intelligence.

Despite substantial science and technological advances over the past two decades that can aid in maintaining and extending the service life of existing nuclear warheads, the CTBT also creates a technical barrier for states with a substantial history of nuclear testing who may in the future see new nuclear warhead designs, such as China, France, Russia, the United Kingdom, and the United States.

According to the exhaustive 2012 study by the U.S. National Academy of Sciences on CTBT technical issues, these states “… are unlikely to be able to deploy new types of strategic nuclear weapons that fall outside the design range of their nuclear-explosion test experience without several multi-kiloton tests. Such multi-kiloton tests would likely be detectable (even with evasion measures) by appropriately resourced … national technical means and a completed IMS network.”15

Tailored Strategies to Bring the Eight Hold-Out States Into the Treaty

Movement toward ratification of the CTBT by the remaining hold-out states would strengthen international and regional security, and each of the remaining eight states have good reason to do so. But in order to make progress, advocates of the CTBT in government and in civil society will need to update and tailor their outreach and diplomacy if there is to be a shift in outdated attitudes of the governments of these eight “hard cases.” CTBT states parties will also need to rejuvenate the bi-annual gatherings of foreign ministerial meetings on the CTBT and signatory states at “Article XIV Conferences on Facilitating Entry Into Force” so they are more impactful.

North Korea: The Democratic People’s Republic of Korea (DPRK)’s nuclear program represents the most direct and immediate threat to the global nuclear-test ban enterprise. Pyongyang’s policies with respect to further nuclear testing and the CTBT are inextricably tied to the resolution of long-running security and political disputes with the United States and South Korea, and to resumptions of sustained negotiations on denuclearization and a peace regime on the Korean peninsula.

Diagnostic cables snake their way across the Nevada Test Site towards the Icecap tower, which housed the diagnostic cannister. One of three U.S. nuclear tests planned for 1993. The test was to have been in the 20-to-150-kiloton range and would have been conducted 1,557 feet underground.  (Photo: National Nuclear Security Administration)As President Trump and South Korean President Moon Jae-in engage in talks with their DPRK counterpart, it is vital that they seek to solidify Pyongyang’s pledge to halt ballistic missile and nuclear testing and close their nuclear test site, and also to bring an end to further North Korean fissile material production.

For now, North Korea possesses enough plutonium for fewer than a dozen bombs, but if left unchecked, it will amass a larger and more potent arsenal. Additional successful nuclear weapon test explosions will improve confidence in the DPRK’s warhead designs and facilitate the mass production of a compact warhead design that can be delivered on its short- or medium-range ballistic missiles. Further tests long-range ballistic missiles, coupled with additional nuclear testing, would likely expand Pyongyang’s nuclear retaliatory potential.

Although the DPRK’s leaders may no longer be willing to negotiate away their nuclear weapon’s program altogether, the regime in Pyongyang still appears to be willing to freeze and possibly abandon portions of his nuclear program in exchange for improved relations with the United States, a reduction of tension on the Korean peninsula, and the possibility of much-needed foreign economic trade and food and energy aid.

On April 21, the DPRK’s supreme leader Kim Jong-un announced that North Korea had developed smaller and lighter nuclear, high-yield nuclear weapons and their means of deliver and could therefore “… discontinue nuclear test and inter-continental ballistic rocket test-fire from April 21, 2018. The northern nuclear test ground of the DPRK will be dismantled to transparently guarantee the discontinuance of the nuclear test.”

He also said that “…the discontinuance of the nuclear test is an important process for the worldwide disarmament, and the DPRK will join the international desire and efforts for the total halt to the nuclear test.”

Now, as the United States and South Korea and other states in the region pursue diplomacy and pressure to achieve denuclearization, they should seek solidify Kim Jong-un’s no testing pledge by securing North Korean signature and ratification of the CTBT, along with confidence building visits by CTBTO technical teams.

Some have suggested the Punggye-ri test site may not be available for additional nuclear tests because of cavity and tunnel collapses caused by previous nuclear blasts. But, in reality the site could still be used for further tests. Clearly, the DPRK’s pledge to close down its main nuclear weapons test site and join the international effort to halt all nuclear testing is a very significant pledge toward denuclearization that clearly puts the DPRK’s accession to the CTBT within reach.

The DPRK’s April 20 announcement to halt nuclear and ballistic missile tests was welcomed by key leaders, including the European Union’s High Representative Federica Mogherini who, in an April 21 statement, called it a “positive, long sought-after step on the path that has now to lead to the country’s complete, verifiable and irreversible denuclearization, the full respect for its international obligations and all relevant UNSC resolutions, and the ratification of the CTBT.”

In a statement to the 2018 preparatory committee meeting for the 2020 NPT Review Conference, the CTBTO’s Executive Secretary Lassina Zerbo also welcomed the DPRK announcement and added that the “CTBT can provide the security and certainty needed by solidifying the commitment to turn away from nuclear testing.”

Kim Jong-un’s remarks on nuclear testing are consistent with the logic expressed years earlier in a statement about nuclear testing and the CTBT that was delivered by a senior DPRK official at a conference in Moscow in 2012:

“Once the CTBT becomes effective … then there is no doubt that it would make a great contribution to the world peace and stability. [However,] unless the U.S. hostile policy and its nuclear threats are completely withdrawn and a solid and permanent peace regime is in place on the Korean peninsula, the DPRK is left with no other choices but to steadily strengthen its self-defensive nuclear deterrent to the standard it deems necessary.”16

As the United States and the international community explores options to achieve the denuclearization of the Korean peninsula, another option, pending the entry into force of the CTBT, would be for North Korea to begin technical cooperation with the CTBTO so that, in the event there is seismic event in North Korean territory, CTBT teams could use their remote monitoring tools, and potentially on-site confidence building visits, to ensure that Pyongyang continues to respect its nuclear test moratorium commitment.

India and Pakistan: Since their destabilizing tit-for-tat nuclear detonations in 1998, India and Pakistan have stubbornly refused to reconsider the CTBT even though neither country has an interest in or technical justification for renewing nuclear testing.

India and Pakistan could advance the cause of nuclear disarmament and substantially ease regional tensions by converting their unilateral test moratoria into legally binding commitments through the CTBT. Pakistan has said it supports the principles and goals of the CTBT and would welcome a legally binding test ban with India, but leaders in Islamabad have failed to take the first step by signing the CTBT.17

In particular, India’s ongoing campaign for recognition as one of the world’s “responsible nuclear-armed states,” its effort to win support for membership in the Nuclear Suppliers Group (NSG), and obtain a permanent seat on the UN Security Council would get a strong boost if leaders in New Delhi would commit to sign and ratify the CTBT.

The NSG’s 2008 decision to exempt India from the full-scope safeguards standard for civil nuclear trade was taken with the understanding that India would continue to observe a complete nuclear-test moratorium.18 The renewal of nuclear testing by India would re-open that decision and jeopardize its hard-won access to the international civil nuclear technology and uranium market—an “intolerable” price to pay, according to former Indian Foreign Secretary Kanwal Sibal, who noted in 2009: “We will suffer international isolation. It will be a huge setback to our bid for permanent membership of the United Nations Security Council.”19

This makes it all the more logical for New Delhi’s leaders to join the nuclear-test ban mainstream and reinforce global efforts to detect and deter testing by ratifying the CTBT.

For their part, UN member states that are serious about their commitment to the CTBT and nuclear-risk reduction should insist that India and Pakistan sign and ratify the CTBT before they are considered for NSG membership and insist that India should sign and ratify the treaty before its possible permanent membership on the Security Council is considered.

The Middle East: Ratification of the CTBT by Israel, Egypt, Iran—all of which must ratify to trigger CTBT entry into force—and Saudi Arabia would reduce nuclear weapon-related security concerns in the region. It would also help create the conditions necessary to achieve their common, stated goal of a Middle East zone free of nuclear and other weapons of mass destruction.20

“As a stepping-stone towards this long-term objective, a ‘nuclear-test-free zone’ could be created in the Middle East, by way of CTBT ratifications by the remaining states of the region,” High Representative Federica Mogherini suggested in June 2016 at special ministerial meeting in Vienna to mark the twentieth anniversary of the treaty.21

Israel was among the first nations to sign the CTBT in 1996 and has been actively involved in the development of the treaty’s monitoring system and on-site inspection mechanisms. Israel’s Permanent Representative to the International Atomic Energy Agency and CTBTO Merav Zafary-Odiz said in 2016 that: “a regional moratorium [on nuclear testing] could enhance security, and potentially lead to a future ratification of the CTBT. Israel has announced its commitment to a moratorium, it would be useful for others to do the same.”

Unfortunately, Israel has hesitated to take the next steps toward its own ratification of the CTBT—a move that would bring that nation closer to the nuclear nonproliferation mainstream and lend encouragement to other states in the region to follow suit.

Iran has signed the CTBT but has not yet ratified. In September 1999, at the first Conference on Facilitating the Entry-Into-Force of the CTBT, Iranian Foreign Minister Mohammad Javad Zarif, then Iran’s deputy foreign minister, spoke in support of the CTBT and later endorsed a UN conference statement calling for cooperation aimed at bringing the treaty into effect.

Iran is understandably focused on the implementation of the 2015 Joint Comprehensive Plan of Action (JCPOA) and eventual approval of the Additional Protocol to its nuclear safeguards agreement—and the future of the JCPOA itself has been put into doubt as a result of the Donald Trump administration’s critical approach to the agreement.

Regardless of the status of the JCPOA, if over time Iran fails to ratify the CTBT and fully cooperate with the operation of IMS monitoring stations in the years ahead, it will add to concerns about the purpose of its sensitive nuclear-fuel activities.

If the JCPOA survives the Trump era, Iran could help assuage concerns about the purposes of its nuclear program as key JCPOA limits on its uranium enrichment program expire over the course of the next ten-to-fifteen years by making clear its support for and intention to ratify the CTBT in a timely manner.

China’s Potential Leadership Role: China decided two decades ago to join the CTBT regime and become one of the treaty’s early signatories. China’s leaders and officials have consistently expressed their support for the CTBT, but it is clear that China has made a quiet decision to stop short of ratification until the United States completes its ratification process.

To most observers outside of China, there does not appear to be any serious political impediments to Chinese ratification at this time, aside from the inaction of the United States on the CTBT. Beijing’s failure to ratify has likely also given cover for India not to consider ratification more seriously and has undermined the credibility of Beijing’s overtures to Pyongyang to refrain from further nuclear test explosions.

Comparison of seismic signals (to scale) of all six declared DPRK nuclear tests, as observed at IMS station AS-59 Aktyubinsk, Kazakhstan. (Credit: Comprehensive Test Ban Treaty Organization)


Recently, however, Beijing has been more energetic in its support for the CTBT. With encouragement from CTBTO Executive Secretary Dr. Lassina Zerbo, China has in the past year certified its first five International Monitoring System (IMS) stations, of the twelve it is treaty-bound to certify in order to realize the completion of the global nuclear test detection system.

The first Chinese IMS station, radionuclide station RN21, was certified in December 2016. The most recent four stations include two primary seismic stations, and two other radionuclide stations, all certified between the months of September to December of 2017. These most recent certifications will “fill in an important geographical coverage gap in terms of event detection in the region,” according to a CTBTO press statement.

During a certification ceremony in January 2018 in China, Zerbo commended China for setting a “positive example” for other Member States in regard to its technical engagement, and Vice Director of Equipment Development at the Chinese Department of the Central Military Commission Lt. General Zhang Yulin noted that the certification of the five stations in one year was “of landmark significance.”

In a statement released following a meeting with Zerbo, Chinese Foreign Minister Wang Yi said that the CTBT is “an important pillar of international nuclear disarmament,” and has an “irreplaceable” role. He also noted that China is “willing to deepen” it’s cooperation with the CTBTO and further “promote the construction and certification of follow-up stations,” which will provide further concentrated monitoring of potential nuclear test activity in the region, particularly North Korean activity.22

The United States: The policy of the United States—which has conducted more nuclear weapon test explosions than all other states combined and has the world’s most potent nuclear arsenal—toward the CTBT is perhaps the most important of all the remaining Annex 2 states. Much has changed since the Senate last examined the CTBT in 1999 and rejected the treaty by a 51-48 margin after a brief and highly partisan debate that centered on questions about the then-unproven program to maintain the existing nuclear warheads in the U.S. stockpile without nuclear explosive tests (a.k.a. the Stockpile Stewardship Program) and the then-unfinished global test-ban monitoring system.23

The substantive case for U.S. ratification of the CTBT is stronger than ever. Today, the global monitoring system can detect any militarily significant nuclear test explosion and U.S. stockpile stewardship programs to maintain its nuclear arsenal without nuclear test explosions has proven to be more effective than originally anticipated.24 The United States no longer has a technical or military need for nuclear explosive testing and it is clearly in U.S. national security interests to prevent other states from testing, which would create new nuclear tensions and enable advances in other states’ nuclear weapons arsenals.

Unfortunately, the U.S. Senate is deeply divided and dysfunctional and has not systematically debated the issues related to the CTBT for nearly two decades. Few senators are familiar with the technical issues surrounding the CTBT or its potential benefits.

Worse still, the Trump administration’s 2017 Nuclear Posture Review (NPR) asserts that “the United States does not support the ratification of the CTBT,” even though there is no technical need to resume nuclear testing.25

The review, which generally defines U.S. policy regarding the role of nuclear weapons in security strategy, says “the United States will continue to support the Comprehensive Nuclear Test Ban Treaty Preparatory Committee” and “the related International Monitoring System and the International Data Center.”

The NPR calls upon other states not to conduct nuclear testing and states that “[t]he United States will not resume nuclear explosive testing unless necessary to ensure the safety and effectiveness of the U.S. arsenal ….”26

The Trump administration’s test ban policy implies that it wants to reap the benefits of the CTBT, including obtaining data from the monitoring system, without fulfilling earlier pledges to reconsider ratification of the treaty. Unfortunately, this policy is not likely going to change during the Trump administration and will not change without stronger international pressure from U.S. allies and civil society. With a renewed push for U.S. leadership on CTBT ratification and movement on the treaty by other hold-out states, it is possible that a new administration and a new Senate will take another look at the CTBT, which is clearly in the U.S. and international security interests.

When the United States does eventually ratify the treaty, it can put additional pressure on other holdout states to follow suit. Until then, it is vital that other states continue to reinforce the global taboo against nuclear testing to reduce the risk of renewed nuclear testing and a dangerous cycle of global nuclear-arms competition.

Bottom Line

Moving closer to the goal of the CTBT’s formal entry into force is the task of every NPT state party, every CTBT state-party, every state that supports the new Treaty on the Prohibition of Nuclear Weapons, and any other state that considers itself a “responsible” nuclear actor, because the CTBT is and will continue to be an essential pillar of the global nuclear nonproliferation and disarmament architecture.

Doing so will, however, take political energy, more diplomatic creativity, and a more serious and sustained commitment from national and international leaders in government and in civil society, beginning now.


1. The eight key states that must still ratify before the CTBT enters into force are: China, the DPRK, Egypt, India, Iran, Israel, Pakistan, and the United States. This onerous requirement is spelled out in Article XIV of the treaty, which references forty-four states listed in Annex II.

2. United States Nuclear Tests 1945 Through September 1992, U.S. Department of Energy, DOE/NV-209, Rev. 14, December 1994; V. N. Mikhailov, editor, Catalog of Worldwide Nuclear Testing, Begell-Atom, LLC 1999; “The Nuclear Testing Tally,” Arms Control Association Fact Sheet, September 2016 https://www.armscontrol.org/factsheets/nucleartesttally

3. Treaty on the Non-Proliferation of Nuclear Weapons, March 5, 1970, Article VI, www.un.org/en/conf/npt/2005/npttreaty.html

4. Ibid., preambular paragraph 11.

5. For a detailed history, see: Jayantha Dhanapala, Multilateral Diplomacy and the NPT: An Insider’s Account (Geneva: United Nations Institute for Disarmament Research, 2005).

6. “The Nuclear Test Ban: Time to Finish What We Started,” by Sergei Ryabkov and Lassina Zerbo, The Diplomat, April 21, 2017. See: https://thediplomat.com/2017/04/the-nuclear-test-ban-time-to-finish-what-we-started/

7. “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

8. In a statement to the UN General Assembly in September 1998, Indian Prime Minister Atal Bihari Vajpayee told the 53rd UN General Assembly that India would not be among the last states standing in the way of the treaty’s entry into force. Vajpayee said that India’s series of five underground tests, conducted on May 11 and 13, 1998, “do not signal a dilution of India’s commitment to the pursuit of global nuclear disarmament. Accordingly, after concluding this limited testing program, India announced a voluntary moratorium on further underground nuclear test explosions.” He went on to say that: “We conveyed our willingness to move towards a de jure formalization of this obligation. In announcing a moratorium, India has already accepted the basic obligation of the CTBT… . We expect that other countries, as indicated in Article XIV of the CTBT, will adhere to this Treaty without conditions.” See: https://www.pminewyork.org/adminpart/uploadpdf/92927lms48.pdf

9. Ayesha Riyaz, Statement of Pakistan before the Ministerial Meeting on the CTBT, June 13, 2016, Vienna. See: https://www.ctbto.org/fileadmin/user_upload/statements/2016_Ministerial_Meeting/Pakistan.pdf

10. “Historic Summit of Security Council Pledges Support for Progress on Stalled Efforts to End Nuclear Weapons Proliferation,” Security Council 6191st Meeting, United Nations Meetings Coverage and Press Releases, September 24, 2009. See: http://www.un.org/press/en/2009/sc9746.doc.htm

11. United Nations S /PV.7776 Security Council Seventy-first year 7776th meeting, 23 September 2016, page 2. See: http://www.un.org/en/ga/search/view_doc.asp?symbol=S/PV.7776

12. Joint Statement on the Comprehensive Nuclear-Test-Ban Treaty by the Nuclear Nonproliferation Treaty Nuclear-Weapon States, Media Note, Office of the Spokesperson Washington, D.C., September 15, 2016. See: http://www.state.gov/r/pa/prs/ps/2016/09/261993.htm

13. Under Article XVIII of the Vienna Convention on the Law of Treaties, which is widely recognized as customary international law, states are obliged not to take actions that would “defeat the object and purpose” of treaties they have signed. Vienna Convention on the Law of Treaties, May 23, 1969, Article 18, https://treaties.un.org/doc/Publication/UNTS/Volume%201155/volume-1155-I-18232-English.pdf

14. Comprehensive Nuclear-Test-Ban Treaty, September 24, 1996, preambular paragraph 5, www.ctbto.org/fileadmin/content/treaty/treaty_text.pdf

15. National Academy of Sciences (NAS), “The Comprehensive Nuclear Test Ban Treaty: Technical Issues for the United States,” 2012, p. 117.

16. Jang Song Chol, Statement to “The Comprehensive Test Ban Treaty (CTBT): Prospects for Making Its Global Benefits Permanent,” presented at the Moscow Nonproliferation Conference, September 6, 2012. See: http://ceness-russia.org/data/page/p915_1.pdf

17. On August 16, 2016, the Pakistani Ministry of Foreign Affairs released a statement on the proposal, noting: “The bilateral non-testing arrangement, if mutually agreed, could become binding immediately without waiting for the entry into force of the CTBT at the international level.”

18. In a September 5, 2008 statement by Pranab Mukherjee, India’s external affairs minister issued on the eve of the key NSG meeting, India’s reiterated its commitment to adhere to a unilateral nuclear testing moratorium among other nuclear restraint pledges. The text of the approved waiver states that it is “based on the commitments and actions” described by Mukherjee. Several states asserted this reference indicated that the group will end nuclear trade with India if it does not honor the Mukherjee statement, particularly if it conducts a nuclear test. In a Sept. 6 statement, New Zealand declared, “It is our expectation that in the event of a nuclear test by India, this exemption will become null and void.” Other states, including Japan and Ireland, offered similar statements. See: “NSG, Congress Approve Nuclear Trade with India,” by Wade Boese, Arms Control Today, vol. 38, no. 8, October 2008.

19. Rama Lakshmi, “Key Indian Figures Call for New Nuclear Tests Despite Deal With U.S.,” Washington Post, October 5, 2009, <www.washingtonpost.com/wp-dyn/content/article/2009/10/04/AR2009100402865.html>.

20. See: “WMD-Free Middle East Proposal at a Glance,” Arms Control Association Fact Sheet, June 2015 https://www.armscontrol.org/factsheets/mewmdfz For more detail on Israel’s position, see: Dr. Paul Chorev, Director General of the Israel Atomic Energy Commission, Statement at the 53rd General Conference of the International Atomic Energy Agency, September 2009 https://www.iaea.org/About/Policy/GC/GC53/Statements/israel.pdf

21. Speech by High Representative of the European Union for Foreign and Security Policy and Vice President of the European Commission Federica Mogherini at the Ministerial-level meeting of the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty, Vienna, June 13, 2016. https://eeas.europa.eu/headquarters/headquarters-homepage/5005/speech-by-high-representative-of-the-european-union-for-foreign-and-security-policy-and-vice-president-of-the-european-commission-federica-mogherini-at-the-ministerial-level-meeting-of-the-preparatory-commission-for-the-comprehensive-nuclear-test-ban-trea_fr

22. Shervin Taheran, “China Adds Monitoring Stations,” Arms Control Today, Vol 48, No. 2, March 2018. https://www.armscontrol.org/act/2018-03/news-briefs/china-adds-monitoring-stations

23. Daryl G. Kimball, “What Went Wrong: Repairing the Damage to the CTBT,” Arms Control Today, Vol. 29, No. 10, December 1999. https://www.armscontrol.org/act/1999_12/dkde99

24. “U.S. Has No Need to Test Atomic Arsenal, Report Says,” by Matthew L. Wald, The New York Times, March 31, 2012. http://www.nytimes.com/2012/03/31/science/earth/us-tests-of-atomic-weapons-not-needed-report-says.html

25. Nuclear Posture Review, U.S. Department of Defense, February 2018, page 63. https://www.defense.gov/News/SpecialReports/2018NuclearPostureReview.aspx

26. Ibid.



More than two decades after the opening for signature of the Comprehensive Test Ban Treaty (CTBT), the treaty has near universal support and has established a global norm against nuclear test explosions. The nuclear testing taboo impedes the development of new and more advanced nuclear warhead designs, which helps prevent dangerous nuclear competition, and maintain international security.

China Adds Monitoring Stations

China has completed certification in the past year of its first five International Monitoring System (IMS) stations of the 12 it is obligated to certify toward the completion of the global nuclear test detection system managed by the Comprehensive Test Ban Treaty Organization (CTBTO). China is among the eight countries, including the United States, that need to ratify the Comprehensive Test Ban Treaty (CTBT) for the 1996 treaty to enter into force. Both countries have signed but not ratified the treaty.

The first Chinese IMS station, radionuclide station RN21, was certified in December 2016. Two primary seismic stations and two additional radionuclide stations were certified during the September-December 2017 period. These stations “fill in an important geographical coverage gap in terms of event detection in the region,” according to a CTBTO press statement. Chinese Foreign Minister Wang Yi said in a statement that the CTBT is “an important pillar of international nuclear disarmament” and that China is “willing to deepen” its cooperation with the CTBTO.

The monitoring system is about 90 percent complete, with more than 290 stations certified. Once complete, the IMS will have 321 monitoring points, consisting of hydroacoustic, infrasound, seismic, and radionuclide stations and 16 laboratories worldwide.—SHERVIN TAHERAN

China Adds Monitoring Stations

North Korea Tests New Long-Range Missile

January/February 2018
By Kelsey Davenport

North Korea tested a new ballistic missile capable of targeting the entire continental United States, a move that considerably extends Pyongyang’s missile flight range.

This December 12, 2017 photo from North Korea's official Korean Central News Agency shows North Korean leader Kim Jong Un in Pyongyang presenting awards to scientists for their successful work on the Hwasong-15 intercontinental-range ballistic missile. (Photo: AFP/Getty Images)The Nov. 29 test took place just before 3 a.m. in North Korea, and the missile flew on a lofted trajectory for 53 minutes before splashing down in the Sea of Japan about 1,000 kilometers from the launch site. The test, which violates UN Security Council resolutions, was firmly condemned by the international community and escalated concerns about a potential pre-emptive or preventative strike by the United States in response to Pyongyang’s nuclear and missile advances.

North Korea’s Korean Central News Agency (KCNA) heralded the test of the intercontinental ballistic missile (ICBM), designated the Hwasong-15, as a success and described the missile as “capable of carrying super-heavy nuclear warhead and attacking the whole mainland of the U.S.”

David Wright, co-director of the Global Security program at the Union of Concerned Scientists, estimated that the missile would have a range of 13,000 kilometers if flown on a standard trajectory, which would put the entire continental United States within its range. U.S. Defense Secretary Jim Mattis confirmed the range capability on Nov. 28 when he told reporters that the missile could hit “everywhere in the world.”

North Korea did test an ICBM, the Hwasong-14, twice in July, but the estimated range of that system is 10,500 kilometers. (See ACT, September 2017.) At that range, Washington, D.C., would likely have been just out of range, and experts assess that the weight of a nuclear warhead would further reduce that missile’s range.

Like the Hwasong-14, the Hwasong-15 is a two-stage, liquid-fueled system. The Hwasong-15, however, has a number of different characteristics, including a pair of rocket engines powering the first stage, unlike the single-engine Hwasong-14.

Michael Elleman, senior fellow at the International Institute for Security Studies, concluded in a Nov. 30 analysis for the website 38 North that the Hwasong-15 could “deliver a moderately-sized nuclear weapon to any city on the U.S. mainland.” Further, the missile is large and powerful enough to carry decoys or countermeasures that would complicate U.S. missile defense efforts, he said.

Elleman also noted improvements on the Hwasong-15 that would give the North Korean weapon additional accuracy. The missile could be fitted with a postboost control system that could be used to adjust the payload’s velocity and positioning, he said.

When asked about the test, U.S. President Donald Trump told reporters on Nov. 28 that the United States “will deal with it.”

The KCNA announcement said that the test accomplished the “historic cause of completing the state nuclear force” and that North Korea had attained its goal of “completing the rocket weaponry system development.”

A South Korean official told Arms Control Today on Dec. 19 not to read too much into the use of the word “complete.” The official said that North Korea is likely directing that comment at a domestic audience because leader Kim Jong Un set the goal of completing the nuclear arsenal in his Jan. 1, 2017, speech. The officials said that “completion” should not be interpreted as an end of tests.

Many experts and officials assess that North Korea will need to conduct additional tests to demonstrate the reliability of the ICBM. There are continuing doubts about whether North Korea has the technology to ensure that a warhead would survive re-entry into the atmosphere.

Mattis told reporters on Dec. 15 that the Hwasong-15 “has not yet shown to be a capable threat against us right now.” Yeo Suk-joo, South Korean deputy minister for defense policy, said on Dec. 1 that North Korea still needs to prove re-entry and warhead activation.

Elleman made a similar point, noting that more testing is necessary to validate the missile’s performance and verify the re-entry system to ensure that the warhead survives re-entry into the atmosphere. If North Korea is willing to accept “low confidence in the missile’s reliability,” Kim Jong Un could declare the Hwasong-15 combat ready after two or three additional tests, he said.

South Korea responded to the missile test by launching its own precision-strike missiles six minutes after the North Korean test. The South Korean response included army, navy, and air force systems, likely demonstrating that the country’s intelligence agencies detected preparations for the test.

South Korean President Moon Jae-in described the North Korean test as a “reckless provocation” and warned that Pyongyang’s actions may drive the United States to consider a pre-emptive strike against North Korea.

Moon’s concerns about a pre-emptive or preventative strike were reinforced by several U.S. policymakers. U.S. Ambassador to the UN Nikki Haley said that the test brought “the world closer to war” and although the United States does not seek a military conflict, “if war does come, it will be because of continued acts of aggression,” such as the ICBM test.

North Korea tested a new ballistic missile capable of targeting the entire continental United States, a move that considerably extends Pyongyang’s missile flight range.

Defense Bill Restricts CTBTO Funding

The most recent annual National Defense Authorization Act, signed into law on Dec. 12, includes language restricting U.S. financial contributions to the Comprehensive Test Ban Treaty Organization (CTBTO), except for funds related to the International Monitoring System, which detects nuclear test explosions. The CTBTO is the international organization that promotes the Comprehensive Test Ban Treaty in advance of its entry into force and builds up its verification regime.

Infrasound arrays at the International Monitoring System station in Greenland is shown in this August 13, 2009 photo. The U.S. defense authorization bill allows for continued contributions to the monitoring system operated by the Comprehensive Test Ban Treaty Organization.  (CTBTO Preparatory Commission photo)The provision was originally inserted into the House version of the bill. Although not included in the Senate bill, the measure was incorporated into the conference bill, which passed the House on Nov. 14 and the Senate two days later.

The bill also includes an assertion that UN Security Council Resolution 2310, passed in September 2016, calling for the treaty’s early entry into force and the continuation of nuclear testing moratoria does not “obligate the United States nor does it impose an obligation” to refrain from actions that would run counter to the treaty. The amendment’s supporters argue that the United States should not be bound by or contribute financially to a treaty the Senate has not ratified. Opponents of the provision contend that it could signal a weakened U.S. commitment to the global moratoria on nuclear testing and undercut support for the treaty.—ALICIA SANDERS-ZAKRE

Defense Bill Restricts CTBTO Funding


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