¹ There is no universally accepted definition of terrorism: assertions regarding the core characteristics of terrorism vary widely among governments and scholars. Recognizing these differences, for the purposes of this paper, the following definition will be used: Terrorism is the calculated use of violence, or the threat of violence, perpetrated by non-state actors in order to achieve social or political goals, with the aim of influencing a wider audience than the immediate victims of the violence and which is usually directed against non-combatants.

² For a discussion of the Lumb panel and other early government efforts to assess the risks of nuclear terrorism Willrich and Taylor (1974, pp. 78–82; Walker, 2001, pp. 107–132).

³ Although the AEC maintained that poor accounting and handling practices probably were responsible for the discrepancy, there was speculation that about 100 kilograms ofbomb-grade uranium from the plant may have found its way to Israel (Gilinsky, 2004).

⁴ Taylor’s views also were popularized in a three part article by John McPhee in 3, 10, and 17 December 1973 issues of The New Yorker (McPhee, 1974).

⁵ Another influential volume in the Harvard series but with a broader focus was the volume by Falkenrath et al. (1998).

⁶ Jerrold Post maintains that, ‘absent a clear understanding of the adversary’s intentions, the strategies and tactics developed [to counter them] are based primarily on knowledge ofterrorists [sic] technological capabilities and give insufficient weight to psychological motivations’ (1987, p. 91). Indeed, Cameron has even asserted that ‘the real driving force behind the heightened danger of nuclear terrorism lies not with the increased opportunities for micro-proliferation, but rather with the changing nature ofpolitical violence and the psychological and organizational characteristics ofterrorism itself (1999, p. 152).

⁷ One of the few systematic efforts to explore terrorist motivational incentives and disincentives for using CBRN weapons in general can be found in Gurr and Cole (2002).

⁸ It should be stated at the outset that it is not necessary for terrorists to be irrational or psychologically imbalanced for them to seek nuclear weapons (Cameron, 1999, p. 23). Cameron further states that ‘If a sufficiently important end were sought by the [terrorist] group, all means, including nuclear terrorism, might be justifiable’ (1999, p. 154).

⁹ A comprehensive discussion of the underlying reasons that would precipitate a goal of causing mass casualties is beyond the scope ofthis paper, but several perspectives will be discussed.

¹⁰ Contagious biological agents that are used to start a large-scale epidemic could conceivably also lead to comparable casualties, although this type of attack has less reliable and less immediate consequences and it is also more difficult to fix the geographical scope of biological attacks than is the case with nuclear weapons.

¹¹ See, for example, Marlo: ‘the increasing willingness to engage in mass murder makes terrorists more likely to consider WMD as usable and even preferable to conventional explosives and other traditional terrorist weaponry (1999, p.55). Also see Falkenrath (1998, p.53) and Foxell (1999, p. 96).

¹² Indeed, if causing colossal numbers of casualties is the sole reason for employing nuclear weapons then, technically speaking, the act does not constitute terrorism but mass murder, since for an act to be defined as terrorism, there must be present the intention to influence a wider audience than the immediate victims.

¹³ For a more in-depth discussion of the issue of audience impact, see Gressang (2001). Also, compare for example, Falkenrath et al. (1998, pp. 206–207) and McCormick (2003).

¹⁴ Albert Bandura has discussed various ways in which terrorist groups legitimize their violent behaviour, several of which can flow from a group’s ideological outlook, including moral justification, displacement of responsibility, ignoring the actual suffering of victims, and dehumanizing victims (Bandura, 1998).

¹⁵ Several authors have questioned the link between a desire on the part of religious terrorists to cause mass casualties and the potential use ofWMD, as well as the extent to which religious actors are oblivious to political concerns. They have also pointed to the large number of CBRN plots on the part of ethno-nationalist terrorists. See, for example, Rapoport (1999) and Dolnik (2004). To the first of these objections, one can refer to the discussion above relating to the desire to cause mass casualties and note that for actors seeking to cause a genuinely catastrophic scale of injury and death, conventional weapons will not suffice. The other objections are addressed in following sections.

¹⁶ For more on these three groups, see chapters by Kaplan, Stern, and Carus in Tucker (2000).

¹⁷ See, for example, the discussion of the group Avenging Israel’s Blood in Sprinzak and Zertal

(2000).

¹⁸ These factors are drawn from a combination of Tucker (2000, pp. 255–263), Campbell (2000, pp. 35–39), and Jackson (2001, p. 203). Many of these factors are related to a group’s capabilities for engaging in nuclear terrorism (discussed in the following section), leading to the obvious observation that, in addition to motives driving capabilities, on occasion capabilities can reciprocally influence a terrorist’s intentions.

¹⁹ The key steps terrorists would have to take on the pathway to a nuclear attack, are discussed in Bunn et al. (2003, pp. 21–31). Also see Maerli (2004, p. 44) and Ferguson and Potter (2005, pp. 112–113).

²⁰ It is beyond the scope of this chapter to detail the various acquisition routes a non-state actor might pursue. For an analysis of this issue see Ferguson and Potter (2005, pp. 18–31).

²¹ A technologically sophisticated terrorist group might be able to achieve success with a smaller amount of HEU if it could construct a ‘reflector’ to enhance the chain reaction.

²² The experiment, however, did not demonstrate how several individuals might obtain key components for an implosion type device, some ofwhich are very tightly controlled.

²³ For a discussion ofpossible routes to acquisition ofintact nuclear weapons, see Ferguson and Potter (2005, pp. 53–61). Potential routes include deliberate transfer by a national government, unauthorized assistance from senior government officials, assistance from the custodian of the state’s nuclear weapons, seizure by force without an insider’s help, and acquisition during loss of state control over its nuclear assets due to political unrest, revolution, or anarchy.

²⁴ Empirically speaking, the record ofnon-use should not be compared over the long history of terrorism, but only over the period since it became feasible for non-state actors to acquire or use nuclear weapons, Circa 1950.

²⁵ See, for example, Ferguson and Potter (2005, p. 40), Jenkins (1986, p. 777), Hoffman (1993a, pp. 16–17), and Clutterbuck (1993, pp. 130–139).

²⁶ Since these weapons were too difficult to acquire and use reliably.

²⁷ Indeed, the former head of the CIA’s Bin Laden Unit has explained that, ‘What al-Qaeda wants is a high body count as soon as possible, and it will use whatever CBRN [chemical, biological, radiological, nuclear] materials it gets in ways that will ensure the most corpses’ (Scheuer, 2002, p. 198).

²⁸ For instance, The Turner Diaries, a novel written by the former leader of the National Alliance, William Pierce, described and which has had considerable influence on many right-wingers, describes racist ‘patriots’ destroying cities and other targets with nuclear weapons (Macdonald, 1999).

²⁹ For one thing, many deranged or excessively aggressive individuals cannot function as part ofa group.

³⁰ Allegedly, subsequent efforts by Aum representatives to meet with Russia’s minister of atomic energy were unsuccessful.

³¹ The farm was purchased for the dual purposes of testing chemical weapons and mining uranium.

³² Following its sarin attack on the Tokyo subway in 1995, Aum reappeared under the name of Aleph. In 2000, Japanese police discovered that the cult had obtained information about nuclear facilities in a number of countries from classified computer networks (Daly et al., 2005, p. 19).

³³ For a discussion of some of the incidents, see Leader (1999, pp. 34–37) and Daly et al. (2005, pp.31-33)

³⁴ For an assessment of these documents, see Albright (2002). Al Qaeda’s nuclear programme: through the window ofseized documents [online]. Policy Forum Online, Nautilus Institute. Available from: http://nautilus.org/acrchives/fora/Special-Policy-Forum/47_Albright.html [Accessed 15 September 2006.]

³⁵ For a review ofsome of these reports see (Daly et al., 2005, pp. 40–45). One of the more sensationalist reports emanating from Israel claimed that the terrorist organization had acquired eight to ten atomic demolition mines built for the KGB (Jerusalem DEBKA-Net-Weekly, 12 October 2001 cited by Daly et al., p. 41). Another report from the Pakistani press suggests that two small nuclear weapons were transported to the US mainland (The Frontier Post, 2001). Ifpress reports can be believed, on occasion, bin Laden and his senior aides have sought to give credence to these stories by bragging oftheir acquisition ofnuclear weapons (Connor, 2004; Mir, 2001). A sceptical assessment ofthese risks is provided by Sokov (2002).

³⁶ Daly et al. provides a related but alternative assessment of the unsuccessful procurement efforts (2005).

³⁷ To some extent, this apparent divergence in threat assessments among experts is due to their focus on different forms ofnuclear terrorism and different time-frames. Nevertheless, there is no clear prevailing view among experts about the immediacy or magnitude of the nuclear terrorism threat. For an extended review ofexpert opinions on various proliferation and terrorist threats -although not precisely the issue ofuse of a nuclear explosive, see Lugar (2005).

³⁸ For a discussion of this and other nuclear pathways involving state sponsorship see Ferguson and Potter (2005, pp. 54–61).

³⁹ Some breakthroughs might lead to weapons that are more likely to successfully detonate, improving success rates but not overall destruction.

⁴⁰ See, for example, the 1983 movie War Games. Schollmeyer provides a review of other fictional accounts of nuclear violence (2005).

⁴¹ Sagan made important study of the broader but related issue of the possibility of achieving fail safe systems in large organizations such as the military (1993).

⁴² The Hiroshima bomb from highly enriched uranium had a yield of between 12.5 and 15 kilotons (Rhodes, 1986, p. 711).

⁴³ Estimates come from Helfand et al. (2002) and Bunn et al. (2003, p. 16). Both derive their estimates from Glasstone and Dolan (1977) and their own calculations.

⁴⁴ Casualty estimates from these two attacks vary by a factor of 2, from 68,000 at Hiroshima (Glasstone and Dolan, 1977)to 140,000 (Rhodes, 1986).

⁴⁵ Whether or not a fire storm is generated would depend on the exact location of the blast. A smaller, ground-based explosion is less likely to trigger a fire storm, but an excess of glass, flammable material, gas mains, and electrical wires might trigger one in a city (Eden, 2004).

⁴⁶ Neither the U.S. Office of Technology Assessment (1979) nor Glasstone and Dolan (1977) attempt to calculate the economic impact of a nuclear attack.

⁴⁷ The actual percentage of those likely to succumb to long-term psychological illness will depend on several factors, including the individual’s proximity to the attack location, whether or not a person became ill, previous exposures to trauma, the individual’s prior psychological state, the presence or otherwise ofa support network and the amount ofexposure to media coverage (Pangi, 2002); for more on the links between terrorism and subsequent psychological disorders, see Schlenger (2002) and North and Pfefferbaum (2002).

⁴⁸ The ratio ofunexposed to exposed patients has been conservatively estimated as 4:1. (Department ofHomeland Security, 2003, p. 34) Department ofHomeland Security Working Group on Radiological Dispersal Device (RDD) Preparedness, Medical Preparedness and Response Sub-Group. (2003). Radiological Medical Countermeasures. Becker notes that estimates state that in any terrorist event involving unconventional weapons, the number of psychological casualties will outnumber the number ofphysical casualties by a factor offive. Becker (2001). Are the psychosocial aspects ofweapons ofmass destruction incidents addressed in the Federal Response Plan: summary ofan expert panel. Military Medicine, 166(Suppl. 2), 66–68.

⁴⁹ This is presuming, ofcourse, that they could not be easily retaliated against and could credibly demonstrate the possession ofa robust nuclear arsenal.

⁵⁰ For more information on the topic of disruptive technologies and their singular adoption behaviour, see Bower and Christensen (1995).

⁵¹ See, in particular, the growing literature on the promise and problems associated with implementing United Nations Security Council Resolution 1540, including Jones (2006).

⁵² As Ehud Sprinzak has argued, ‘the vast majority of terrorist organizations can be identified well in advance … and the number of potential [WMD] suspects is significantly less than doomsayers seem to believe. Ample early warning signs should make effective interdiction of potential superterrorists much easier than today’s prevailing rhetoric suggests’ Sprinzak (2000, pp. 5–6).