On Nuclear Terrorism. By Michael Levi, Harvard University Press, November 2007, 224 pp.
Reviewed by William C. Potter
Michael Levi’s slender volume On Nuclear Terrorism is a valuable addition to the burgeoning literature on catastrophic terrorism. Unlike many recent studies, it neither hypes the nuclear threat nor discounts it. Instead, Levi sketches the obstacles a terrorist would need to overcome to successfully implement a nuclear attack and then discusses the panoply of means available to preclude that outcome. Although many of the challenges and preventive measures have been discussed in much greater depth elsewhere, Levi’s study adopts a systems analysis perspective to demonstrate the power of an integrated, multilayered defense.
Underlying Levi’s concept of defense as a system is the premise that, in order for a defense against nuclear terrorism to be effective, it only needs to succeed at one stage in the terrorist chain of events. In contrast, the terrorist must successfully complete each step in the plot to acquire fissile material or an intact nuclear explosive, fabricate a nuclear weapon, deliver the weapon to the target, and detonate the explosive. Although any element or layer of defense may be relatively ineffectual, Levi argues that a carefully conceived and integrated, multilayered defense stands a much better chance of obstructing a nuclear attack than may at first appear to be the case.
This approach leads Levi to exploit what he calls “Murphy’s Law of Nuclear Terrorism,” what can go wrong (from a terrorist’s perspective) might well go wrong. In other words, understanding the various ways in which terrorists might fail provides insights and potential tools for increasing the odds of terrorist failure. This perspective, in turn, suggests the importance of understanding both terrorist capabilities and their attitudes toward risk and failure.
Levi’s work, like most analyses of nuclear terrorism, does not delve very deeply into terrorist motivations. Yet, it does highlight the intriguing finding by several analysts that many terrorist organizations, including al Qaeda, appear to be tactically conservative and risk averse from an operational standpoint; they may be very willing to risk their lives, but not in futile operations. This tendency may not dissuade a terrorist organization from embarking on the very challenging tasks of devising and implementing a nuclear strike, but it suggests a number of opportunities for exerting countervailing pressures that may reinforce their cautionary inclinations and steer them away for the pursuit of high-consequence but low-probability acts.
In reviewing the various barriers in the path of a would-be nuclear terrorist, Levi correctly identifies state stockpiles of fissile material as the “gateways to nuclear terrorism” and emphasizes the importance of security at the source. As Graham Allison famously observed, “[N]o nuclear material, no nuclear bomb.” Unfortunately, the world currently is awash in fissile material, including about 500 metric tons of separated plutonium and more than 1,700 tons of highly enriched uranium (HEU), enough for tens of thousands of nuclear weapons. Although the overwhelming majority of this amount resides in the United States and Russia, more than a dozen states are estimated to possess at least 25 kilograms of HEU, the minimum quantity needed for a nuclear weapon, according to the International Atomic Energy Agency.
In Search of a Nuclear Fort Knox
A number of approaches have been employed with varying degrees of success in order to secure nuclear weapons-usable material at the source. They include materials protection, control, and accounting (MPC&A). Although Levi does not dispute the desirability of providing the same degree of MPC&A for nuclear material as gold is afforded at Fort Knox, he observes a number of difficulties in achieving a gold security standard for nuclear material. One problem pertains to the fact that although the precise amount of gold in storage is known, there is no reliable figure for the amount of global stocks of HEU and plutonium. Indeed, physical inventories have never been conducted in some countries. In addition, although the movement of gold from Fort Knox is very limited (only very small quantities are reportedly ever removed, for purposes of testing its purity), significant quantities of HEU and plutonium are on the move frequently, especially between facilities within a country, but also on occasion internationally. As a consequence, although the Fort Knox analogy may be useful from an aspirational standpoint, one must look more closely at the existing deficiencies in MPC&A to appreciate both the promise and potential for preventing leakage of fissile material into the hands of terrorists.
One of Levi’s important observations in this respect is his recognition of the human dimension to physical protection. In other words, although the three G’s (guns, guards, and gates) are important, the major limits to physical materials protection and material control pertain to human factors such as the presence or absence of a highly developed nonproliferation and security culture and the commitment by political leaders to expend the resources necessary to make MPC&A a national priority.
Although Levi calls attention to the problems posed by deficient political will and underdeveloped culture, he does not offer much guidance about how to correct the deficit, which arguably requires a long-term investment in nonproliferation education and training in order to change mindsets on the part of nuclear custodians as well as nuclear industry officials. He also ignores a number of other promising approaches for reducing the risk of fissile material leakage, including the minimization or elimination of HEU use in the civilian nuclear sector.
Buyers and Sellers
One of the more interesting and original sections of Levi’s book pertains to the economics of illicit nuclear trade. Price, he notes, will present a major barrier to all but the wealthiest terrorist organizations and, in principle, could be manipulated to impede terrorist acquisition of fissile material. For example, he suggests that intelligence and law enforcement entities “might attempt to purchase nuclear materials themselves, driving terrorists out of the market.” Such action, however, also might have the unintended effect of attracting more nuclear suppliers and thieves to the illicit market place. As a consequence, Levi believes sting operations directed at buyers rather than sellers are a more promising approach and could increase uncertainty for terrorists in the market for nuclear goods and services. As such, the authorities “could raise [the terrorists’] perceived chances of failing and hence the odds that a risk-averse terrorist group would be deterred.”
Analogies are often drawn between the trade in narcotics and illicit nuclear trafficking. Although these comparisons typically are put forth to illustrate the amount of nuclear material trade that may have gone undetected (i.e., approximately 20 confirmed cases of smuggling fissile material are just the tip of a much bigger iceberg), Levi cites other drug trade statistics to indicate the potential for even very imperfect border security to disrupt a nuclear terrorist’s plans. For example, he notes estimates by the U.S. Drug Enforcement Agency that 10-15 percent of the cocaine leaving South America for the United States in 2004 was lost or seized in the transit zone and that the “combined probability that cocaine departing South America destined for the United States will actually make it to the United States” was between 35-70 percent. Although these figures and profit margin may still be attractive for drug smugglers, it is less obvious that nuclear traffickers possessing a relatively small supply of material would judge similar odds to be favorable. As such, even less-than-airtight border controls could significantly affect the calculus of would-be nuclear terrorists and might be particularly effective against failure-averse organizations.
INDs vs. Intact Nuclear Weapons
In principle, would-be nuclear terrorists could choose to build their own nuclear explosive or an improvised nuclear device (IND) or seek to purchase or steal an intact nuclear weapon. The chain of necessary conditions for these two types of nuclear terrorism is different, as are the opportunities for frustrating their occurrence.
The potential for nonstate actors to build an IND has been acknowledged by experts for many years, and most concur with the view of the U.S. National Research Council that “crude HEU weapons could be fabricated without state assistance.” There is much less agreement among specialists, however, about how technically competent terrorists would have to be to make a gun-type device or how large a team they would need.
At one end of the spectrum is the view that a suicidal terrorist could literally drop one piece of HEU metal on top of another piece to initiate an explosive chain reaction. At the other end are some senior Russian nuclear officials who continue to deny that nonstate actors could fabricate a nuclear explosive even if they were able to obtain enough fissile material. Levi stakes out a middle position, which recognizes the possibility of terrorist-manufactured INDs but emphasizes the multiple barriers that would have to be overcome, including acquiring a sufficient quantity and quality of fissile material, reshaping the material to meet nuclear explosive specifications, avoiding accidents such as spontaneous ignition, and initiating the explosion. In this respect, he tends to portray the task as far more demanding than several other recent accounts. For example, although he does not directly challenge the assumptions of the widely publicized article by Peter Zimmerman and Jeffrey Lewis on the prospects for terrorists to build a bomb on a “terror farm,” he correctly notes that it will not be a simple task to find experienced farmers and appropriate utensils, not to mention the necessary seed stock of fissile material.
Levi’s discussion of the prospects for terrorist acquisition of an intact nuclear weapon is less satisfying and focuses primarily on scenarios in which states transfer nuclear weapons to nonstate actors either intentionally or as a consequence of their collapse. He largely ignores the risks posed by thousands of nonstrategic or tactical nuclear weapons that remain in Russian and U.S. nuclear arsenals. These weapons represent a particular concern from the standpoint of nuclear terrorism because of a combination of their physical properties and basing modes. Their relatively small size; portability; and, in the case of some older systems, the lack of electronic locks, as well as their forward deployment, make tactical nuclear weapons the likely weapon of choice for a nuclear terrorist organization. These are also the weapons for which there are no legally binding and verifiable arms control restraints in place.
A Way Forward?
Levi’s brief survey of nuclear terrorism pathways is designed less to probe in depth the various points where vulnerabilities exist than to counter worst-case thinking and to direct attention to the potential for reforming defense against “realistic threats.” Although the parameters of these real but less-than-worst-case expectations are not defined, Levi provides a number of very reasonable guidelines for policymakers to follow: (1) improve security for nuclear weapons and materials; (2) emphasize defensive measures that simultaneously address both nuclear terrorism and other terrorist threats; (3) mandate a strategic intelligence assessment that covers the entire spectrum of nuclear terrorist threats, not only the worst possible case; (4) foster an integrated defensive system that promotes domestic and international intelligence sharing and cooperation on nuclear terrorism; and (5) audit defensive efforts to increase confidence that they work in practice as well as theory.
Levi’s first recommendation essentially embraces the dictum that the first priority should be to secure material at the source. As he properly observes, the effective application of this approach has the virtue of not only preventing nuclear terrorism directly, but also increasing the effectiveness of broader (secondary) defensive measures should terrorists find the means to overcome the initial defenses.
The main insight of Levi’s second tenet is the value added of conceiving defenses that serve to protect against nuclear and non-nuclear terrorist threats. Here, Levi has in mind not only measures that enhance intelligence collection and analysis, but efforts to counter terrorist financing and enhance export controls.
One of the fundamental deficiencies in most governmental and nongovernmental analyses of nuclear terrorism is the failure to tap expertise that crosses the terrorism and nuclear weapons divide. Few analyses display familiarity with both domains, and much of what passes for analysis is particularly shallow in treating the diversity of terrorist types, their motivations, and the means available for affecting the tactical and strategic calculations of terrorists. In addition to recognizing this serious shortcoming, Levi suggests a number of means to improve strategic intelligence assessments, including the development of a wider range of scenarios and more public vetting of assessments in order to build public support for strategies that address less-than-worst-case threats.
It is difficult to exaggerate the challenge of effectively managing the existing counterterrorism system involving diverse and often competing organizational interests at the local, state, federal, and international levels. Unlike some analysts, Levi is skeptical that a top-down approach to coordination, such as a czar for nuclear terrorism, would effectively overcome bureaucratic obstacles to coordination. Instead, he argues that the best alternative is to “provide departments and agencies with a framework within which to plan their activities and with a tool to use in justifying and seeking funding for those programs.” The key to coordination, he believes, is the development of a system or framework that enables those responsible for implementing policy to view how the different pieces in the system fit together as an integrated defense.
Finally, Levi maintains that an effective defensive system must include the means to evaluate its efforts wisely. One must continually test the system as a whole to identify weaknesses and assess, as best as possible, its applicability against realistic threats. Exercises that involve red teaming against multiple variations on possible threats, he suggests, are important components of this testing process.
Levi’s argument about the need to conceive of defense against nuclear terrorism as a broad and integrated system makes a great deal of sense. His specific recommendations for achieving that system also generally are sound as far as they go and offer useful insights for thinking about the nature of nuclear terrorism and what can be done to reduce the probability of its occurrence. Yet, the recommendations, as well as the analysis on which they are based, are presented more in the form of snapshots than fully developed arguments. As a consequence, one is left to ponder a number of questions. What are the less-than-worst-case nuclear threats on which we should be focused? Do they primarily involve the theft of HEU or plutonium or tactical nuclear weapons? Should we concentrate principally on those geographical regions and states where most of the material and weapons are located or on those nuclear facilities that are least secure? What would a broad defensive framework actually look like, and how should a new U.S. administration move to implement it? What can be done to more effectively implement the proliferation of new international initiatives to counter nuclear terrorism?
Levi astutely calls attention to the likely operation of Murphy’s Law of Nuclear Terrorism as it applies to terrorists. Unfortunately, one also must be attentive to the probable operation of a similar law as it pertains to the U.S. government’s efforts to combat nuclear terrorism. In other words, as we adjust our sights to deal with less-than-10-foot terrorists, we should not discount the possibility that poorly conceived and implemented U.S. foreign policy can serve as a terrorist growth hormone. That is not an argument for focusing most of our resources on the worst-case scenario, but it cautions against completely ignoring that threat.
William C. Potter is the Sam Nunn and Richard Lugar Professor of Nonproliferation Studies at the Monterey Institute of International Studies. He also directs the James Martin Center for Nonproliferation Studies. He is co-author of The Four Faces of Nuclear Terrorism (2005).
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1. The focus of Levi’s book is on high-consequence nuclear terrorism. It does not specifically address the higher-probability but lower-consequence threats posed by radiological dispersal devices and attacks on or sabotage of nuclear energy facilities.
2. There are a variety of variations of Allison’s quote, a long version of which is, “It is a basic matter of physics: without fissile material, you can’t have a nuclear bomb. No nuclear bomb, no nuclear terrorism.” See Graham Allison, “How to Stop Nuclear Terror,” Foreign Affairs, Vol. 83, No. 1 (January/February 2004), p. 64.
4. Some nongovernmental experts believe the International Atomic Energy Agency figure is much too high. See, for example, Thomas B. Cochran and Christopher E. Paine, “The Amount of Plutonium and Highly-Enriched Uranium Needed for Pure Fisson Nuclear Weapons,” Natural Resources Defense Council, April 13, 1995.