The Comprehensive Test Ban Treaty: Ten Years Later…Still a Horrible Idea

In keeping with his campaign promises, Barack Obama will probably pursue a number of arms control measures relatively early in his presidency. One of these is the Comprehensive Test Ban Treaty (CTBT). First rejected by the Senate nearly 10 years ago, the world situation has not altered in a manner that would make the treaty more viable or appropriate. If anything, the CTBT is an even worse idea now than it was in the late 1990s.

The CTBT first opened for signature on September 26, 1996, having been negotiated by the Conference on Disarmament over the previous three years. According to Annex 2 of the treaty, all 44 states that participated in the ’96 Conference on Disarmament must ratify the treaty before it can come into force. Parties to the Treaty have two primary obligations: (1) Not to carry out any nuclear weapon test explosion or any other nuclear explosion, and to prohibit and prevent any such nuclear explosion at any place under its jurisdiction or control; and (2) to refrain from causing, encouraging, or in any way participating in the carrying out of any nuclear weapon test explosion or any other nuclear explosion. Thus, the Treaty bans any and all “nuclear explosions.” Long perished are the days when the peaceful uses of nuclear explosions were researched extensively.

There are three interrelated reasons why the U.S. should not ratify the treaty. These will be addressed in turn. First of all, the fundamental objective of the CTBT is at odds with official U.S. policy. The preamble of the CTBT states that “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 nuclear proliferation in all its aspects…an end to all such nuclear explosions will constitute a meaningful step in the realization of a systematic process to achieve nuclear disarmament.” Thus, the goal of the CTBT is nuclear disarmament. In contrast, the overwhelming consensus in the U.S. is that the current international environment does not currently permit disarmament. Even the Obama campaign declared that “Obama and Biden will always maintain a strong deterrent as long as nuclear weapons exist.” Were the U.S. to ratify the treaty and observe its provisions, this would indeed have a negative impact on the ability to retain the arsenal, but this is not in the interests of the U.S. During a speech to the Carnegie Endowment in late October, Robert Gates placed the commitment to nuclear disarmament in proper context:

Try as we might, and hope as we will, the power of nuclear weapons an their strategic impact is a genie that cannot be put back in the bottle – at least for a very long time. While we have a long term goal of abolishing nuclear weapons once and for all, given the world in which we live, we have to be realistic about that proposition.

The continued need for a nuclear deterrent should alone provide sufficient rationale for rejecting the treaty. However, U.S. politicians have always attempted to have their cake and eat it too, arguing that the U.S. would be able to sign the CTBT to advance nonproliferation goals while simultaneously keeping its own arsenal for as long as necessary. In that same speech to the Carnegie Endowment, where he reiterated the need to retain nuclear weapons, Secretary Gates replied to a question about the CTBT and stated that he thought the U.S. should ratify the treaty. Aside from the logical inconsistency of this position, there are scientific and technical challenges that make this course of action untenable. In short, observing the CTBT would undermine and erode the credibility of the U.S. nuclear deterrent.

The U.S. has not conducted a nuclear test since 1992, when President Bush signed legislation that restricted nuclear testing. Prior to this, the safety and reliability of the deterrent had always been assured through an extensive testing program. To substitute for this, President Clinton introduced the Science Based Stockpile Stewardship Program (SBSS), which involved the annual certification of the stockpile’s safety and reliability using techniques that do not involve testing. However, it is unlikely that SBSS program alone is sufficient to certify the arsenal over the long term. In his speech to the Carnegie Endowment, Gates spoke on the long-term viability of the deterrent:

Let me first say very clearly that out weapons are safe, reliable, and secure. The problem is the long-term prognosis – which I would characterize as bleak. We can and do re-engineer our current stockpile to extend its lifespan. However, the weapons were developed with narrow technical ‘margins.’ With every adjustment, we move farther away from the original design that was successfully tested when the weapon was first fielded. Add to this that no weapons in our arsenal have been tested since 1992 – so the information on which we base our annual certification of the stockpile grows increasingly dated and incomplete. At a certain point, it will become impossible to keep extending the life of our arsenal – especially in light of our testing moratorium.

What is not often remembered today is that when Clinton first proposed the SBSS program, there were serious doubts as to whether it was even possible; to gain support for the CTBT and SBSS, Clinton had to promise that were the arsenal to fail its annual certification, the President would invoke the supreme interest clause of the CTBT, withdrawal from the treaty, and resume testing. The technologies and methods supporting SBSS are still not mature and would be a major scientific achievement in their own right. The SBSS program was conceived solely as a means to facilitate the CTBT; its scientific feasibility was a secondary concern. Clinton himself admitted as much in 1993 when he commented that “Additional nuclear tests could help us prepare for a CTB (comprehensive test ban) and provide additional improvement in safety and reliability. However…these benefits would be outweighed by the price we would pay in conducting the tests now – through undercutting our nonproliferation goals.”

Even if the science undergirding SBSS was realistic, there are other factors that are degrading the program’s effectiveness. The U.S. nuclear weapons program is suffering a major brain drain as older and more experienced weapons designers retire and their younger replacements do not have first-hand experience in actually designing a warhead. As they retire, the personnel most familiar with the weapons will not be available to assist in the certification process. Nor is there even a large base of test data that SBSS could draw upon, since much information gleaned from previous tests was not recorded due to security concerns and the assumption that regular testing would always be part of the program.

U.S. nuclear weapons are extremely sophisticated devices with thousands of different components in a single warhead. In the history of the U.S. nuclear program, many problems were only discovered after a device was subjected to the extreme heat and stress of a nuclear explosion. Some problems were completely unanticipated by the designers before the test took place. One-third of the weapons that existed in the nuclear arsenal in the late 1980s encountered problems after deployment that required testing to resolve. Testing actually discovered the problems in three-quarters of these cases. Replacing individual components of nuclear weapons as warheads age could create problems that would only be revealed by a nuclear test. As the fissile material within each warhead undergoes radioactive decay its ability to achieve supercritical mass upon detonation may be compromised. The heat released from the decay could damage other components of the warhead.

In addition to the technical and scientific problems, there are other ways that the lack of testing can compromise the deterrent. The changing geopolitical realities may produce military contingencies that demand new types of nuclear weapons which cannot be produced without testing. The safety of the arsenal as a whole could be compromised since some older designs lack certain safety features, and adding such features may not be possible without testing. As the U.S. cuts its nuclear arsenal in accordance with START I, SORT, and unilateral presidential directives, the variety of warheads in the inventory will decrease. Even if a problem is detected through the SBSS program, an entire class of weapons might be brought offline until the issue is resolved. This could immediately compromise the nuclear deterrent by removing a significant portion of deployed weapons, possibly leading to the deactivation of one or more legs of the triad. And the enormous consequences of failure to certify could pressure SBSS managers and technicians to overlook problems and issue false assessments.

As mentioned earlier, there are two ways the U.S. could observe the CTBT and still keep a viable arsenal. The first is to remanufacture the weapons to their original specifications, the method that Russia uses to maintain its stockpile. This option is probably not viable for the U.S. since the nuclear weapons infrastructure has been in a state of decay since the late 1980s and is probably not able to support a major rebuilding program. The second option is to manufacture a new warhead design that tolerates design inefficiencies in exchange for high reliability. This is the purpose of the proposed reliable replacement warhead (RRW). However, the RRW has not yet been funded by congress, and it is questionable whether the new administration will continue the program. In any case, while the U.S. could select either of these options and adhere to the CTBT, the result would be a case of policy schizophrenia, since the underlying purpose of the the treaty is to retard the development and retention of nuclear weapons. This would certainly invite the same international accusations of cynicism and duplicity (which I wish the U.S. had more of, anyway).

Finally, the CTBT is unlikely to stem nuclear proliferation, which is the principle rationale offered by proponents of the treaty. The primary impact of the CTBT would be to impede the development and retention of nuclear weapons in the established nuclear powers, which have sophisticated arsenals of highly-advanced, multi-stage thermonuclear weapons. Smaller states could still develop crude fission weapons with designs that could function without nuclear testing. Pakistan and India maintained a nuclear capability for several years before nationalist political pressures forced them to test. North Korea has been considered a nuclear power since the early 1990s, and only tested in 2006. Israel has developed a relatively sophisticated weapons without conducting a known test. South Africa developed a small arsenal without testing, though the 1979 “Vela Incident” suggests a covert nuclear detonation over the Southern Ocean. The A.Q. Khan network was in possession of several reliable weapon designs, which it disseminated to a number of states, including Libya and Iran. In short, a determined proliferator could succeed in gaining a nuclear weapon without testing, as has been demonstrated numerous times.

Furthermore, there are serious doubts about the verifiability of the treaty. The preparatory commission of the CTBT has established a network of hundreds of different monitoring stations using several different techniques to detect a nuclear detonation. Many of the stations lie within the political jurisdiction of the state that would be conducting the test, making them highly vulnerable to neutralization and interference before the test actually occurs. For example, the vast expanse of Russia requires that numerous monitoring stations be placed within its territory; those stations closest to the test site could be easily disabled through whatever means, thereby compromising any evidence of a nuclear test and giving Russia plausible deniability if accusations were brought against it.

The CTBT International Monitoring System (IMS) may not be able to detect low-yield tests or those that are conducted evasively. Militarily significant data can be obtained from yields as low as 10 kilotons. The IMS can detect tests of about 1-kiloton that are conducted nonevasively. However, evasive testing could be conducted with little risk of detection. Detonating a weapon in a subterranean cavity – a technique known as cavity decoupling – can muffle the blast signature by a factor of 70. Thus, the signature from a 1-kiloton explosion can be reduced to that of a 14-ton explosion. Yields this low may be impossible for the IMS system to detect, and even if they were detected, the could be indistinguishable from other seismic events such as mining explosions, small earthquakes, volcanic activity, etc. Test yields in the pound range – such as in hydronuclear testing, which achieves supercriticality, but not a full nuclear yield – would be impossible to detect through the IMS system.

Aside from the limited capabilities of the IMS system, the CTBT contains no enforcement provisions other than the dissemination of IMS data to treaty members. This alone is unlikely to deter testing. During the 1990s, Russia was suspected of conducting several low-yield tests on Novaya Zemlya, but it faced no serious recriminations from the U.S. or the international community. This demonstrates that the political will to confront suspected violators may not exist, especially since low-yield tests produce small signatures that are ambiguous and open to multiple interpretations.

One could be excused for dismissing the CTBT as little more than a utopian fantasy from the arms control community. Even President Carter was reluctant to enter a treaty that did not allow low-yield testing, since such tests were always considered integral to the safety and reliability of the stockpile and low-yield detonations were difficult to detect anyway. And yet, the incoming administration is intent on resurrecting this monstrosity despite its deserved rejection by the Senate in 1999. Let hope that it is  rejected by the Senate again, or better yet, the new President correctly assesses it for what it is: a flawed Treaty, fundamentally at odds with official U.S. policy, that would erode the credibility of the U.S. nuclear deterrent and fail to stem nuclear proliferation. Without the approval of the RRW or a large-scale remanufacturing program, it is vital that the U.S. retain the option to resume nuclear testing if necessary.