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LOOKING BACK: The U.S. Senate Vote on the Comprehensive Test Ban Treaty

Damien J. LaVera

This month marks the fifth anniversary of one of the most self-defeating moments in the U.S. Senate’s history of involvement in international arms control. On Oct. 13, 1999, that body voted 51-48 against ratifying the Comprehensive Test Ban Treaty (CTBT), slowing efforts to bring the treaty into force; stalling progress on the broader arms control agenda; and foreshadowing the Bush administration’s new, aggressively unilaterlist approach to national security.

Still, even without U.S. ratification, the continued and increasing global support for the CTBT has helped sustain a 13-year-old U.S. test moratorium, brought about a de facto global moratorium, and helped pave the way for the treaty’s eventual entry into force when conditions permit.

Prior to the vote, CTBT opponents argued that the treaty would not be verifiable, that the long-term safety and reliability of our nuclear stockpile could not be ensured without nuclear testing, and that the treaty would be of limited nonproliferation value.[1]

Perhaps the most important question was whether the CTBT’s verification and monitoring regime would be capable of deterring and detecting clandestine tests. Opponents argued that this would not be possible because a zero-yield test ban is inherently unverifiable. As Sandia National Laboratory Director Paul Robinson said, “[I]t is very unlikely that the threshold for detection and yield measurement in most parts of the world will ever reach the level to identify these yields as nuclear tests, and hence as violations to the U.S. understanding of the treaty’s central obligation.”[2]

Five years later, however, the evidence suggests that the treaty’s verification and compliance regime is up to the task. Take, for instance, the August 2000 explosions that sunk the Russian submarine, the Kursk, in the Baltic Sea. Seismic monitoring stations clearly identified two explosions: one small precursor explosion, followed by a much larger blast 135 seconds later. The second explosion, estimated to be 250 times more powerful than the first, was determined to be equivalent to five tons of TNT.[3] By comparison, the smallest yield for a U.S. nuclear test was the July 1962 test of a shoulder-fired tactical nuclear weapon with a yield of 18 tons,[4] while the smallest of India’s 1998 nuclear tests was claimed to have a yield of 0.2 kilotons, 40 times stronger than the Kursk explosion.[5]

The treaty’s monitoring system has also been helpful in evaluating two high-profile explosions in North Korea: the April 2004 railcar explosion and last month’s explosion in the North Korean mountains. The Comprehensive Test Ban Treaty Organization (CTBTO) reportedly used data collected by the International Monitoring System (IMS) to correct inaccuracies in North Korean statements about the railcar explosion,[6] while reports indicate that IMS monitoring data helped determine that last month’s explosion was not a nuclear test.[7]

These examples demonstrate that IMS detection and monitoring capabilities are highly accurate, are already proving their value to the international community, and will only grow more effective and important as the system is completed. They also confirm the conclusions of a July 2002 National Academy of Sciences (NAS) review of the technical issues involved with the CTBT, which determined that “underground explosions can be reliably detected and can be identified as explosions, using IMS data, down to a yield of 0.1 [kiloton] (100 tons) in hard rock if conducted anywhere in Europe, Asia, North Africa, and North America. In some locations of interest…this capability extends down to 0.01 [kiloton] (10 tons) or less.”[8] Add to this impressive capability the data collected not just by the IMS but also through national technical means and other systems deployed for reasons other than treaty compliance, along with the treaty’s onsite inspection provisions, and would-be cheaters face a virtually impenetrable gauntlet of verification measures.

Although CTBT supporters recognized the effectiveness of this system during the 1999 debate, no one could have predicted the seismic shift in the U.S. policy toward arms control verification following the vote. Sen. Jon Kyl (R-Ariz.) correctly said that effective verification and enforcement provisions are “minimally necessary for sensible treaties.”[9] In the last four years, however, the Senate has ratified the Strategic Offensive Reductions Treaty, which contained no special verification measures, and the administration has decided against pursuing verification and enforcement provisions in proposed fissile material cutoff treaty negotiations. What impact, if any, this will have on the CTBT is still not clear.

Stockpile Stewardship

During the 1999 debate, CTBT opponents also argued that a permanent test ban would undermine the U.S. nuclear deterrent. Critics claimed that “testing has been the essential element that has maintained the viability of our stockpile” and that the inability to conduct nuclear tests would lead to intolerable levels of uncertainty in determining the safety and reliability of remanufactured weapons.[10] Kyl said in 2000 that Los Alamos scientists working to re-establish our ability to make plutonium pits were “struggling with this very problem.”[11]

Here again, the record suggests that these concerns were unfounded. As General John Shalikashvili, former chairman of the Joint Chiefs of Staff, noted in his January 2001 report, “The nation’s arsenal is safe, reliable, and able to meet all stated military far into the future as we can see.”[12] The NAS report confirmed that conclusion, noting that historically the United States has conducted very few nuclear tests for stockpile maintenance purposes, that the U.S. approach to maintaining confidence in stockpile safety and reliability has always relied on nontesting means, and that nuclear testing would add little to the Stockpile Stewardship Program in terms of maintaining confidence in the assessment of the existing stockpile.[13] The report also concluded that the United States 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 and “properly focused on this task.”[14]

Those resources, as expected, have been provided—and more. Between fiscal years 2001 and 2004, National Nuclear Security Administration (NNSA) nuclear weapons funding has risen by 19 percent to well more than $6 billion a year.[15] The secretaries of defense and energy have certified the safety and reliability of the stockpile every year, with no indication that this will change in the foreseeable future. Even the pit production issue cited by Kyl has apparently been addressed, at least enough to permit Secretary of Energy Spencer Abraham to testify in March 2003 that the “NNSA is installing an interim pit-production capability at Los Alamos. Later this year Los Alamos will deliver a W88 pit that will meet all the quality manufacturing requirements for use in the stockpile.”[16]

All of this confirms that the only realistic reason the United States would need to resume nuclear testing would be to confirm a new design. Unfortunately, this is precisely the direction some in Congress and the administration would like to head. In 2003, Congress repealed the 1993 Spratt-Furse amendment, which prohibited research and development leading to new types of nuclear weapons. The Department of Energy’s fiscal year 2005 budget request called for $484.7 million through 2009 for research and development on a modified nuclear bunker-buster bomb and other “advanced concepts” designed to destroy deeply buried, heavily reinforced underground facilities. Congress also mandated that the time required to prepare the Nevada Test Site for testing be reduced to 18 months. Administration spokespersons continue to assert that there are no plans to resume testing, but these developments suggest an alarming trend in precisely this direction.

Impact on Nonproliferation

The third issue during the Senate debate in 1999 was the treaty’s effect on curbing nuclear proliferation. CTBT supporters warned that rejecting the CTBT would undercut long-standing U.S. and international nuclear nonproliferation objectives, but critics suggested that its importance to nonproliferation was exaggerated. They argued that it would not stem proliferation because states do not need to test weapons built from proven designs and that the treaty would not add a new nonproliferation norm or legal barrier to proliferation because it would ban the testing of weapons that states are prohibited under the nuclear Nonproliferation Treaty (NPT) from possessing in the first place. In many respects, this is true: a state with a proven design for a Hiroshima-type nuclear weapon, for example, and enough fissile material to make one could build such a bomb without testing it, and the NPT does prohibit the non-nuclear-weapon states from possessing nuclear weapons. The CTBT is intended to fortify the nonproliferation regime, however, by placing an additional barrier in front of those states seeking advanced nuclear weapons. Without the treaty, the international community is forced to fight that battle without one of its most important weapons.

In any case, although normative arguments such as these are difficult to prove or disprove, the past five years have shown that treaty supporters were correct on at least one key point: the decision not to ratify the treaty has undercut efforts to strengthen and expand the arms control treaty regime. The vote robbed the United States and the international community of the leverage needed to convince India and Pakistan to sign the test ban and halt the production of fissile material. Momentum toward strengthening the NPT regime, most notably by implementing the enhanced International Atomic Energy Agency safeguards protocol developed to strengthen NPT verification, has been undermined, and no additional multilateral arms control agreements have been concluded since the vote.

The U.S. failure to ratify the CTBT is not solely to blame for these developments, as many would have occurred under the Bush administration regardless of the vote. Nevertheless, in retrospect, the failure to ratify the CTBT was the first step by the United States toward abrogating its leadership of the international arms control treaty regime. Without that leadership, these and other nonproliferation efforts have clearly stalled.

Where Are We Headed?

Without U.S. ratification, CTBT entry into force remains a distant prospect. The lack of leadership from the United States has stymied efforts to bring the treaty into force. The Bush administration has taken nearly every opportunity to undercut the treaty, boycotting three consecutive conferences of CTBT states-parties, denying support to the CTBTO for onsite inspections, and voting or speaking against the CTBT in the UN General Assembly and the First Committee on Disarmament and International Security and during NPT meetings. The 11 other states that must ratify the treaty before it can enter into force share some of the burden, but little is likely to happen until the United States revises its position.

Not all CTBT news over the last five years has been bad, however. Despite the uncertainties over entry into force, the roster of states that have signed and ratified the treaty has grown steadily, demonstrating the depth of international commitment to bringing the treaty into force, universalizing it, and strengthening the international norm against nuclear testing. To date, 172 states have signed the treaty, and 119 have ratified it, including 67 that have done so since the Senate vote in 1999. This is an astonishing achievement considering that the treaty cannot enter into force without the United States.

Progress in building the IMS has also been impressive. When the system is complete, more than 85 countries will host 321 monitoring stations. The CTBTO Preparatory Commission, which has signed Facility Agreements with 30 states, recently announced that the IMS now monitors the entire globe.[17] This system, unprecedented in its comprehensiveness, sophistication, and effectiveness, is a noteworthy accomplishment and a valuable asset.

For the CTBT, the road ahead begins with the moratorium on nuclear testing. The United States has not conducted a nuclear test in 13 years, and none of the other NPT nuclear-weapon states have done so since 1996. Maintaining that status quo is crucial, as even a single test by one of these states would fracture the moratorium permanently, jeopardizing the treaty. Continued progress in universalizing the treaty and ensuring that the IMS is fully operation when the treaty enters into force is also essential.

The CTBTO must be fully funded so the technical means to monitor compliance remains in place. International support for the CTBT remains high, but states may eventually balk at contributing funds to implement a treaty that they believe may never enter into force. Following through on measures agreed to at the 2003 CTBT Entry Into Force Conference should be helpful in this regard. Of these, creating bilateral, regional, and multilateral initiatives to promote entry into force; establishing a trust fund to support outreach promoting the treaty; and continuing to promote the nonsecurity applications of the IMS should be particularly valuable.

Finally, proposals for provisional entry into force may also be worth considering, particularly if Democratic nominee Sen. John Kerry (Mass.) wins the November election or the Bush administration moderates its anti-CTBT stance in a second term. Provided it is crafted in a way that avoids provoking the United States to withhold CTBTO funding or withdrawing its signature of the treaty, a protocol on provisional application by which the CTBT states-parties agree to permit all or most of the treaty to take effect pending formal entry into force could be a useful mechanism for further institutionalizing the treaty and promoting its universality.


The Senate’s vote against ratification of the CTBT was one of the lowest moments in the history of international arms control. Although the principal arguments presented by critics of the treaty have been shown to be incorrect, entry into force remains out of reach. Nonetheless, considerable progress has been made in implementing and universalizing the treaty. If the international community continues and expands on these efforts, it will be well prepared to bring this crucial treaty into force when the prevailing climate changes.


1. Daryl Kimball, “What Went Wrong: Repairing the Damage to the CTBT,” Arms Control Today, December 1999, pp. 3-9.

2. Jon Kyl, “Why the Senate Rejected the CTBT and the Implications of its Demise,” Proliferation Roundtable speech to the Carnegie Endowment for International Peace, June 5, 2000.

3. “Bannergram,” IRIS Newsletter 2000, no. 1, p. 27.

4. Stephen I. Schwartz, Atomic Audit: The Costs and Consequences of U.S. Nuclear Weapons Since 1940 (Washington, DC: Brookings Institution Press, 1998), pp. 156-157 fn. 117.

5. “NRDC Nuclear Notebook: Known Nuclear Tests Worldwide, 1945-98,” Bulletin of the Atomic Scientists, November/December 1998.

6. “Train Blast Eight Times Bigger Than Claimed by North Korea,” BBC Monitoring International Reports, May 15, 2004.

7. Rob Edwards, “North Korea Blast Not a Nuclear Test,”, September 13, 2004; Christopher Torchia, “N. Korea Snubs N-test Speculation,” Boston Globe, September 14, 2004.

8. Committee on Technical Issues Related to Ratification of the Comprehensive Nuclear Test Ban Treaty, Technical Issues Related to the Comprehensive Nuclear Test Ban Treaty (Washington, DC: National Academy Press, 2002), p. 5.

9. Remarks by Senator Jon Kyl on the CTBT, Oct. 12, 1999, Congressional Record, 106th Congress, S12338-30, s12368-71.

10. Kyl, “Why the Senate Rejected the CTBT.”

11. Ibid.

12. General John M. Shalikashvili (Ret.), Findings and Recommendations Concerning the Comprehensive Nuclear Test Ban Treaty, January 4, 2001.

13. NAS CTBT report, p. 3.

14. Ibid., p. 34.

15. Christopher Paine, “Coddling the Nuclear Weapons Complex,” Arms Control Today, May 2004, pp. 3-9.

16. Spencer Abraham, Testimony Before the Senate Committee on Armed Services, March 20, 2003.

17. David Ruppe, “Earth Fully Covered by Nuclear Test Surveillance System, Official Says,” Global Security Newswire, September 17, 2004.

Damien J. LaVera, co-author of Cornerstones of Security: Arms Control Treaties in the Nuclear Era (University of Washington Press), has worked on test ban issues in the Office of the Special Advisor to the President and Secretary of State for the Comprehensive Nuclear Test Ban Office and for the Lawyers Alliance for World Security.








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