“What's really strikes me about ACA is the potential to shape the next generation of leaders on arms control and nuclear policy. This is something I witnessed firsthand as someone who was introduced to the field through ACA.”
– Alicia Sanders-Zakre
June 2, 2022
The Status of CTBT Entry Into Force: the United States
Share this

By Daryl G. Kimball, Executive Director


VERTIC Seminar on the Comprehensive Test Ban Treaty on the Occasion of The Fourth Article XIV Conference on Accelerating Entry Into Force, September 22, 2005


Ten years ago, the United States decided to pursue a “zero-yield” Comprehensive Nuclear Test Ban Treaty (CTBT), opening the way to the successful completion of negotiations and the endorsement of the treaty here at the United Nations in September 1996.

The CTBT is the product of decades of hard work, dedication, and advocacy by key governmental leaders and perhaps even more importantly, by NGOs, scientific experts, and millions of ordinary people around the world. They have long understood that ending nuclear testing is essential for three powerful reasons: to impede the development of new types of nuclear warheads and reduce dangerous nuclear arms competition; to obstruct the emergence of new nuclear powers; and to prevent further devastation of human health and the global environment.

In the context of today’s ongoing tensions between nuclear weapons states and would-be nuclear weapons states, illicit nuclear trading, and efforts by the nuclear weapon states to improve their nuclear weapon capabilities, the CTBT is more important than ever. Its entry into force is overdue.

Article XIV of the CTBT requires that a specific list of 44 states must ratify before the treaty formally enters into force. Sadly, a relatively small but important set of CTBT rogue states stand in the way. The failure of the U.S. Senate to give its advice and consent for ratification in 1999, the current administration's opposition to the treaty, and the reluctance of 10 other key states to approve the treaty means that the formal entry into force of the treaty is still years away.

Achieving CTBT entry into force will require still more work on the part of concerned governments and civil society organizations.

To alter the current stalemate on the CTBT, there must be renewed leadership in Washington for the reconsideration and ratification of the CTBT. This leadership is not there at the moment. There is the outside chance that positive action on the test ban by China or by India and Pakistan might serve as a catalyst for action, but it is vital that key U.S. Senators help put the treaty back on the map through hearings, work with their colleagues, and through exchanges with technical experts and allied governments.

To keep the chances for U.S. ratification and CTBT entry into force alive, it is also vital the international community not abandon the goal of CTBT entry into force and that key governments continue to press publicly and privately for the CTBT at every opportunity, including this Article XIV Review Conference.

Improving the prospects for CTBT entry into force requires a multifaceted approach. Failure in any one of the following areas could unravel the test moratorium, sink the CTBT, and lead to a dangerous action reaction cycle of nuclear proliferation:

  1. Maintaining the U.S. test moratorium and signature on the CTBT;
  2. Blocking new U.S. nuclear weapons research and development that could lead to the renewal of nuclear testing;
  3. Effectively maintaining the U.S. nuclear arsenal in the absence of nuclear test explosions;
  4. Sustaining Strong U.S. financial support for the CTBT Organization Preparatory Commission;
  5. Improving test site monitoring and transparency measures to better detect and deter possible clandestine nuclear testing.

1. Maintaining the U.S. Test Moratorium and Signature on the CTBT

Shortly after taking office the senior Bush officials announced they would not ask the Senate to reconsider the CTBT. Since 2001, the United States has voted "no" on UN resolutions supporting entry into force of the CTBT and the White House has boycotted the 2001, 2003, and 2005 Article XIV conferences of states parties to promote the treaty's entry into force.

The administration has tried to deflect domestic and international criticism of this policy by insisting that there are no immediate plans to resume testing. But at the same time, the Bush team has considered or pursued a series of moves that could erode the technical and legal barriers blocking the resumption of testing.

In early 2001, Undersecretary of State for International Security and Arms Control, John Bolton, sought a legal analysis on whether the President could unilaterally withdraw the CTBT from the Senate, thus killing any chance it might be reconsidered. The legal brief he received judged that only the Senate has the authority to discharge the treaty from the executive calendar and that a majority vote was required to do so. It is likely that a majority of the Senate would oppose such an action if the Republican leadership initiated it.

Meanwhile, as reported by The New York Times in May 2002, officials from the Office of the Secretary of Defense circulated a memorandum in January 2002 that proposed that President Bush repudiate the United States 1996 signature on the CTBT, which, under a common understanding of international law (Article XVIII of the Vienna Convention on Treaties) still bars it from conducting nuclear test explosions. Officials at the National Security Council, then preoccupied with the war in Afghanistan and other matters, chose not to schedule a meeting to consider the proposal.

It is still possible that officials in the George W. Bush administration might still seek to repudiate the U.S. signature, though I believe it to be unlikely so long as international pressure on the United States to ratify the treaty continues and is communicated at the highest levels.

2. New Nuclear Weapons Research and Development

The Bush administration has also initiated new nuclear weapons research on the basis of the erroneous notion that new nuclear weapons capabilities are useful and necessary to fulfill future U.S. military needs. If it does propose and win Congressional approval for research and development on new nuclear warhead types, the next step could be a proposal to conduct a series of proof-tests to confirm the designs and induct them into the arsenal. Due to strong domestic opposition, however, the possibility of such an outcome in the near-term has greatly diminished.

The Pentagon's January 2002 Nuclear Posture Review (NPR) calls for the development of new nuclear weapons capabilities to provide a wider range of options to defeat "hardened and deeply buried targets" and chemical and biological threats. That year, the President asked Congress for $15.5 million for fiscal 2003 for research on a modified version of existing high-yield nuclear warheads, known as the robust nuclear earth penetrator, or RNEP.

In 2003, the Bush administration proposed that Congress should repeal a ten-year old law prohibiting research leading to development of new, low-yield nuclear weapons. The administration requested another $15 million for research on the RNEP and an additional $6 million for research on new nuclear weapon designs. Congress narrowly approved the repeal and the research monies, but stipulated that work beyond the research phase for any new type or modified type of nuclear warhead would require explicit congressional authorization.

The Bush administration narrowly won approval for these programs on the basis of the argument that they only wanted to conduct research on these weapons.

In 2004, the administration raised its budget request for fiscal year 2005 funding for research on the Robust Nuclear Earth Penetrator (RNEP) to $27 million and outlined a five year spending plan for research and development on two versions of RNEP that would cost at least $485 million. In the same budget request, the administration sought an additional $9 million to fund "advanced concepts" for new types of nuclear weapons.

The good news is that support for these proposals is steadily eroding. In mid-2004, an amendment to the defense authorization bill offered in the House that would have transferred the RNEP monies to conventional munitions research lost by only ten votes: 214-204. In late-2004, Congressional appropriators, led by Ohio Republican David Hobson, eventually cut monies for RNEP research and transferred monies to a new program ostensibly for building more reliable versions of existing warhead types.

This year, the Bush administration renewed its request for authorization and appropriation of funding for research on the RNEP. Once again, Congress is divided as to whether it should appropriate the $8.5 million requested for RNEP. With sustained NGO work and leadership from our allies on Capitol Hill, I would predict that Congress will not fully support the research on modified or new nuclear weapons in the coming year. Support for actual development of the RNEP will be even more difficult for the administration to win if it does decide to pursue that course.

3. Maintaining the U.S. Nuclear Arsenal in the Absence of Test Explosions

Though the Energy Department has determined each year for the last decade that the U.S. nuclear arsenal remains safe and reliable without nuclear testing, critics of the test ban like Dale Klein, the executive chairman of the Nuclear Weapons Council, still claim that "as time goes on there will likely have to be some tests performed beyond the small scale" to address possible aging problems in the nuclear stockpile.

In October 2002, the former director of the Nuclear Weapons Council suggested in a memorandum that the nuclear weapons laboratories "readdress the value of a low-yield [nuclear explosive] testing program." They have. In 2003, in a secret meeting in Omaha, dozens of executive branch officials debated this question and others related to the future of the nuclear weapons stockpile.

The good news is that the group decided there is no reason to resume nuclear testing for such purposes. The reason is simple. As the July 2002 National Academy of Sciences panel, reported, the U.S. "has the technical capabilities to maintain confidence in the safety and reliability of its existing nuclear-weapon stockpile under [a test ban], provided that adequate resources are made available to the Department of Energy's nuclear-weapon complex and are properly focused on this task."

According to the National Academy panel, which included three former lab directors, age-related defects mainly related to non-nuclear components can be expected, but nuclear test explosions "are not needed to discover these problems and is not likely to be needed to address them." Rather, the panel says, the key to the stewardship of the arsenal is a rigorous stockpile surveillance program, the ability to remanufacture nuclear components to original specifications, minimizing changes to existing warheads, and non-explosive testing and repair of non-nuclear components.

However, as I mentioned above, the Bush administration has initiated a new and poorly defined program to design and build new warheads to “replace” certain warhead types already in the arsenal. This “Reliable Replacement Warhead” program, or RRW for short, could become a problem. The impetus for the program is the belief among many lab officials and some Congressional members that the current approach to stockpile stewardship is unsustainable and unreliable. The Department of Energy said in 2005 that the goal of the RRW program is to produce a small quantity of new replacement warheads by 2012-2015 for the W-76 warhead, which is widely deployed on U.S. submarine-based ballistic missiles.

While the RRW proponents claim the program will actually reduce the possibility that the United States might resume nuclear testing to test fixes in the current arsenal, it is possible that if the warhead designs are too extensively reworked, technical uncertainties may arise that lead some in the U.S. nuclear, military, or political establishment to press for the resumption of nuclear testing.

Furthermore, given the fact that current U.S. nuclear doctrine calls for new nuclear capabilities to help make nuclear weapons more “useable” in warfare, the RRW program may also open the way to research, development, production, and even testing of new nuclear warheads with new military capabilities. Even if nuclear testing is not required, such work may provide other states with cause or an excuse to pursue new nuclear weapons capabilities and spur further nuclear arms competition.

To head off these possibilities, all states possessing nuclear weapons should agree to halt all qualitative improvements in their nuclear warheads, whether or not these improvements constitute new warhead designs that might require nuclear proof testing or new “replacement” warheads or “modifications” of existing designs that provide new military capabilities.

4. U.S. Support for the CTBTO and International Monitoring System

Most Bush administration officials, even those who do not support CTBT ratification, recognize that the United States benefits from monitoring capabilities that are currently only available through the CTBT’s International Monitoring System (IMS), including monitoring stations in Russia, China, and other sensitive locations that the United States would otherwise not be able to access. As a result, the U.S. has continued to pay the majority of its annual contribution to the CTBTO Preparatory Commission.

However, in 2001, the administration decided to suspend U.S. technical and financial support for short-notice, on site inspections available only if the CTBT enters into force. The move has made it even more difficult for the Secretariat of the CTBTO Prep Com to collect annual dues owed to the organization by several key states.

While U.S. continues to support the IMS, its opposition to CTBT entry into force has made it more difficult to obtain financial support for the CTBTO from other countries which are concerned that the treaty may never formally enter into force. In addition, the CTBTO Provisional Technical Secretariat’s work is vulnerable to cuts in the United States’ contribution to the effort, which comprises some 20% of the organization’s annual budget.

This coming year for instance, it is quite possible that the U.S. contribution will be cut due to across the board budget reductions in Washington. In January, the Bush administration requested (and the House appropriators later approved) $14.35 million for the CTBTO’s IMS-related activities, which is $7.65 million below the U.S. assessment.

On February 16, 2005, Secretary of State Rice explained that the  "... cut in funding for the International Monitoring System does not signal a change in U.S. policy toward the Comprehensive Test Ban Treaty. The U.S. continues to support and participate in those activities ... that pertain to the IMS, and the U.S. has no plans to press the [CTBTO] to lower its budget .... Unfortunately, budgets are very tight and cuts had to be made, even among programs supported by the administration."

On July 20, Senators Joe Biden (D-Del.) and Richard Lugar (R-Ind.) won the Senate’s support for a $5 million increase above Bush administration’s request. Now, the difference between the House and the Senate appropriations must be resolved in a conference committee in the coming weeks.

Further reductions of the U.S. contribution would put the United States further in arrears and would have a severe impact on the ability of the CTBTO to operate at all. It may also erroneously be interpreted by some states as a sign that the United States is preparing to get back in the business of nuclear weapons testing.

5. Improving Test Site Monitoring and Transparency Measures

Ongoing activities at the U.S., Russian, and Chinese test sites, primarily in the form of subcritical nuclear experiments, may breed allegations that Russia or China are conducting surreptitious nuclear test explosions. In fact, in the spring of 2002, U.S. intelligence officials briefed Congress that they believe that Russia may have conducted supercritical nuclear experiments at the Novaya Zemlya test site. While this assessment was based on limited information and was technically-flawed, it reveals the risks of operating in a climate of opacity and suspicion.

Additional test site transparency initiatives could address future uncertainties and clear up erroneous allegations. In fact, in 2001, Russia proposed "additional verification measures for nuclear test ranges going far beyond treaty provisions," but neither the United States nor Russia have seriously pursued this concept.


The CTBT has been and remains a vital part of a comprehensive approach to global security dangers. Despite the obstacles still facing the CTBT, the treaty is already working. It has reinforced the 14 year-old U.S. test moratorium and helped to bring about the de facto global nuclear test moratorium which exists today. In the absence of a requirement for a new nuclear warhead, a defect in an existing weapon that cannot be addressed without resuming testing, and the perception that clandestine nuclear testing has occurred, the seven states that have conducted nuclear test explosions are not likely going to do so again. Even India and Pakistan, which complicated the conclusion of the CTBT negotiations in Geneva in 1996 and which conducted nuclear test explosions in 1998, have declared testing moratoria.

Nevertheless, the longer it takes to achieve CTBT entry into force, the likelihood that one or another state will someday break the global taboo against nuclear testing will increase. Achieving CTBT entry into force requires a substantial shift in attitudes about the value of the test ban and new nuclear weapons in the White House and the Senate, as well as effecting changes in government policy in India, Pakistan, China, and Israel.

My organization, the Arms Control Association, and many other civil society organizations appreciate the steady support for the CTBT as demonstrated by numerous statements made by individual governments and regional groupings at Article XIV conferences, at the 2000 and 2005 NPT Review Conferences, the United Nations General Assembly, and strong support for the treaty expressed by the European Union, the Non-Aligned Movement, and the Organization of American States (despite objections raised by the United States).

Although these statements and activities are important, they are not sufficient. Delegates at this conference must realize that while the Bush administration's active opposition to the treaty is damaging to the prospects for entry into force, it is not for the Bush administration alone to decide the fate of the treaty, which remains on the calendar of the U.S. Senate and which may be reconsidered by the next U.S. administration.

We therefore urge the governments represented at this conference to actively urge -- at the highest level -- the U.S. administration to join the list of responsible and civilized states and reconsider its opposition to the treaty. If they are serious in their support for nuclear nonproliferation, they must not shrink from confronting CTBT hold out states and urge them to reconsider their positions though sustained diplomacy in the years ahead.

The CTBT alone will not stop proliferation, but further nuclear proliferation cannot be checked without the CTBT's entry into force. We still have a lot of work to do.


The Arms Control Association (ACA) is a non-partisan, non-profit organization established in 1971 to promote public understanding of arms control issues and to promote effective nuclear, biological, chemical, and conventional arms control solutions. ACA publishes the monthly journal, Arms Control Today.