Among the chilling details unearthed in the manifesto of Norwegian domestic terrorist Anders Behring Breivik were passages advocating the use of biological weapons and especially Bacillus anthracis, the bacterium that causes anthrax. Most commentators rightly downplayed the issue, since no evidence has emerged that Breivik obtained the bacterium or the capability to produce and disseminate it.  At the same time, Breivik’s manifesto is yet another data point highlighting the appeal that biological weapons generally, and B. anthracis in particular, have to extremist groups and individuals seeking to cause mass casualties.
The most extensive non-state biological weapons program unearthed to date was organized in the 1990s by the Japanese Aum Shinrikyo cult.  Together with the 2001 letters containing B. anthracis mailed to the media and U.S. Congress, it is one of only two known non-state efforts to try to manufacture and disseminate aerosolized biological weapons or B. anthracis. Especially with so few cases on which to base analysis, Aum provides a key data point for assessing bioterrorism risks. But while much has been written about the group, most analysis has focused either on its successful chemical weapons attacks or the cult’s bizarre characteristics more generally. Aum’s failed biological weapons program has received far less attention, presumably in part because of a paucity of information. 
A recent report based on extensive interviews with key cult members, including some imprisoned and on death row in Japan, sheds new light on Aum’s biological weapons-related activities. The research effort that culminated in the publication of Aum Shinrikyo: Insights Into How Terrorists Develop Biological and Chemical Weapons was spearheaded by Richard Danzig, who served as Secretary of the Navy in the Clinton administration, and is a longtime advocate in Washington’s inner sanctums of more robust efforts to counter bioterrorism.  For full disclosure, this author worked on the early stages of the multi-year research effort that culminated in the report, though not the drafting of the final paper. The following draws on that work generally and the recently released report specifically.
Prior to the Danzig et al. study, key cult members had apparently never been debriefed in any detail about their biological weapons program. Japanese authorities were more interested in the chemical weapons program, because it produced casualties, than the biological weapons program that appears to have failed. It is unclear whether outside analysts had previously tried to gain access to imprisoned cult members, which would have required the cooperation of the Japanese government.
Newly available information about Aum’s biological weapons efforts provides grounds for both comfort and concern. The group grappled with challenges that will confront many non-state actors that might hope to employ biological weapons. Yet Aum’s struggles appear to have had as much to do with its often bungling approach as with the inherent challenges of deploying biological weapons, and future groups may navigate these challenges less ineptly. The ways in which Aum failed, and the trade-offs it confronted, provide lessons for policymakers looking to disrupt the efforts of future non-state actors that aspire to wield biological weapons.
From Yoga, Massage, and Alternative Medicine to Catalyzing the Apocalypse
Aum Shinrikyo began as a peaceful group before gradually morphing into an apocalyptic millenarian cult. The group evolved from a yoga studio founded in Tokyo in the mid-1980s by Chizuo Matsumoto (who later renamed himself Shoko Asahara), a semi-blind acupuncture, massage, and Chinese medicine practitioner.  Aum drew members stifled by a lack of purpose and spirituality in their lives, an early core of whom became Asahara’s inner circle.
The group grew rapidly; by 1989, it comprised about 4,000 members, and by 1995, when the cult carried out the sarin gas attacks on the Tokyo subway and Asahara and other key cult members were consequently arrested, it had about 10,000 members in Japan.  The cult controlled about two dozen properties in Japan and had foreign offices in the United States, Germany, and Russia. 
As early as 1985, Asahara predicted a coming apocalypse and identified himself and his acolytes as key to averting it. Over time, this prediction morphed into a belief that the apocalypse was inevitable but cult members alone would survive it, and finally that the cult should hasten the apocalypse by launching attacks, including with biological weapons. 
The group’s descent into violence was gradual. In late 1988, a follower accidentally drowned during ritual exercises, and fearing attention from authorities Asahara ordered his corpse burned and remains disposed of surreptitiously. When the deceased’s best friend became disillusioned with the cult and attempted to leave it early the following year, he was killed. A few months after that, Asahara ordered the killing of a lawyer representing families of cult members, and cult members also killed the lawyer’s wife and one-year-old son. 
One striking aspect of the Aum case is that roughly a dozen members of the inner circle personally carried out various criminal acts, including assassinations and the dissemination of biological and chemical agents. Cult rank-and-file appear to have assisted, likely often unknowingly, for example by staffing chemical and biological weapons production facilities, but appear not to have been directly involved in carrying out attacks. For members of the inner circle, crossing lesser thresholds to illegal action and violence appears to have reduced inhibitions to carrying out subsequent, more transgressive acts, and also made it difficult for members to contemplate leaving, since they were criminally implicated.
The trigger for the cult’s shift from apocalypse survival to apocalypse initiation appears to have been its unsuccessful attempt to compete in Japan’s 1990 parliamentary elections, on which it spent millions of dollars but garnered only a token number of votes.  The group’s efforts to develop apocalypse-hastening weapons melded science and science fiction; members were fascinated by futuristic weapons concepts such as plasma guns that could atomize human bodies or mirrors several miles across that would float in space and reflect the sun’s rays.  Several cult members visited the archive of Nicolai Tesla in Serbia to research his writings about earthquake-generating machines.  The cult purchased land in Australia with the intention of prospecting for uranium to build nuclear weapons.  And Aum purchased military hardware from the former Soviet Union, including AK-47 assault rifles, production equipment to manufacture its own versions in Japan, and a surplus MI-17 military transport helicopter, although its procurement efforts—like its later biological weapons efforts—were characterized by short attention spans and short shrift to technical challenges. 
While some of Aum’s efforts are best characterized as science fiction, the cult’s pursuit of chemical and biological weapons was substantially grounded in science. Chemical weapons were pursued in parallel with and ultimately as a substitute for failed biological weapons efforts. The cult reportedly manufactured small quantities of phosgene, hydrogen cyanide, soman, GF and VX nerve agents, and attempted to employ some of these in targeted assassinations, consistently without success.  It produced and disseminated larger quantities of sarin, with which it was able to kill and injure on several occasions.  Although Aum apparently dabbled with a variety of biological agents, it only seriously attempted to obtain and disseminate two, botulinum neurotoxin (BoNT), obtained from the bacterium Clostridium botulinum, and B. anthracis. The focus of this brief is Aum’s biological weapons efforts, which have received relatively little attention to date and on which the Danzig et al. study sheds more new light.
Botulinum Neurotoxin: Trying to Deploy the Most Potent Poison
After deciding that the lawyer representing cult members’ families should be killed, Asahara asked his disciples what the most potent poison was, and one replied, “botulinum.” Although not employed to assassinate the lawyer, after the humiliating 1990 electoral defeat Asahara ordered the toxin’s acquisition. 
As with B. anthracis, the cult chose not to try to obtain C. botulinum from legitimate culture collections, presumably fearing such a mode of acquisition could be traced back to Aum following any attacks.  Instead, cult members gathered soil from an area known to contain the bacterium with the intention of culturing it.  The cult may also have obtained material from a South American culture collection.  One key cult member recalls the group worked with at least five distinct strains of C. botulinum, suggesting that some effort was made to isolate C. botulinum from the thousands of other bacterial and fungal species a soil sample would contain, though no information sheds light on the methods by which the cult attempted this task.  If no isolation was attempted, that would provide one clear explanation for the apparent abject failure of Aum’s C. botulinum efforts, since a soil sample would contain thousands of living bacterial and fungal species that would crowd out any desired C. botulinum the samples might have contained.
Cult members cultivated material in two very large, crude, homemade fermenters; whether these were capable of maintaining the anaerobic (oxygen-free) environment or temperatures required is unclear. No efforts were made to purify the resulting yellow liquid, a mixture of growth media and bacteria. According to a key cult member, at least some of the product was contaminated with Bacillus [subtilis] natto, an aerobic bacterium used in Japan to ferment soybeans, although how the contaminant was identified remains unclear.  Enormous volumes of the yellow liquid were supposedly produced; based on data provided by interviewed cult members Danzig et al. estimate total production at a remarkable 450 metric tons. 
Given the challenges Aum faced and its crude approach, the cult’s efforts to produce BoNT unsurprisingly appear to have been unsuccessful. Mice on which the yellow liquid was tested showed no toxic effects, and one cult member reportedly slipped into a fermenting tank and nearly drowned, but subsequently showed no signs of illness.  In early 1990 the cult nonetheless disseminated large volumes of the liquid from trucks fitted with crude spray devices, deploying these in the vicinity of two U.S. Naval bases, the Narita airport, the Japanese Diet, the Imperial Palace, and the headquarters of a rival religious group.  No one appears to have been affected (including cult members who accidentally exposed themselves during the dissemination process), and the efforts went unnoticed by legal authorities.
In fall 1990, three Aum leaders were arrested for fraudulently purchasing land for a new compound; unbeknownst to the police, chemical weapons production facilities were under construction on the new land. According to a key cult member, the arrests were interpreted as a sign that a police raid was imminent, and Aum responded by dismantling its chemical and biological weapons facilities.  In 1992 the cult reinvigorated its efforts with a new focus on B. anthracis, detailed below. When these efforts failed to produce any casualties, in 1993 the group again attempted to produce BoNT and used small quantities of material it produced to unsuccessfully attack individuals and a subway station. 
A variety of factors may have contributed to the failed BoNT efforts. Several analysts have speculated that Aum may not have acquired a strain of C. botulinum capable of producing significant toxin.  Available information suggests the cult may simply have cultured a soil sample without attempting to isolate C. botulinum, which would not have yielded meaningful quantities of toxin even if the sample had contained a toxin-producing strain alongside thousands of other organic contaminants.
Even if the group did acquire and isolate a toxigenic strain, conditions for appropriate anaerobic fermentation may not have been achieved. Two cult members indicated the presence of bacterial contamination, and this would have interfered with the growth of C. botulinum.  It is also possible that some toxin was successfully produced but degraded or destroyed during processing, storage, or dissemination, or that whatever toxin was present was too dilute to have an effect. The most likely hypothesis remains that the cult failed to obtain or isolate the requisite bacteria.
Bacillus Anthracis: “Genetic Engineering” to Produce Lethality?
In 1992, Aum reinvigorated its biological weapons efforts in the context of more robust militarized interaction with the outside world, the trigger for which seems to have been leader Asahara’s whims rather than any particular external event.  Efforts now focused on B. anthracis, the bacterium that causes anthrax. As with the C. botulinum, Aum decided not to try to obtain material from a culture collection for fear the acquisition could be traced. An unsuccessful effort was apparently made to steal a strain from a laboratory, after which a cult sympathizer provided access to a vaccine strain of the material, although the details remain murky. 
Perhaps the most important puzzle on which the Danzig et al. report sheds potential light is with its alternative theory about how the cult ended up with a vaccine strain of B. anthracis. The conventional wisdom is that this represented bungling, possibly as simple as a clerical error when ordering material from a culture collection. Others have suggested that the anthrax dissemination was only intended as a trial run, or that the effort was sabotaged.  Danzig et al. advance a plausible, if still speculative, alternative explanation.
The cult member in charge of biological weapons efforts had completed undergraduate studies in agricultural and veterinary medicine at a university with a substantial anthrax collection, including both Sterne and Pasteur vaccine strains, before going on to PhD studies in virology.  Danzig et al. speculate that a contact at his old university provided him with B. anthracis, a supposition supported by new analysis of the samples gathered by the Japanese police, which suggest that the cult’s material closely matched the particular strain of Sterne held by the university. 
Two key cult members indicated that Aum members working on the project were aware they had a vaccine strain but planned to use “genetic engineering” to convert it to a more lethal form. While other analysts have dismissed this as more science fiction than science, Danzig et al. speculate that the cult may have obtained both Sterne and Pasteur strains and sought to combine them to produce a virulent strain.  It turns out that Russian scientists had published a paper detailing such an effort in 1989, and scientists at the Japanese agricultural and veterinary university had been working on the technique around the same time.  It bears emphasizing that no concrete evidence suggests the cult obtained a Pasteur strain, and even if it had, employing Sterne and Pasteur strains to create a virulent pathogen is a challenging task almost certainly beyond cult members’ capabilities.
As with BoNT, in 1993 the cult began attempting to mass produce B. anthracis without evidence that it had successfully obtained a pathogenic strain. Material was prepared in crude drum fermenters. No efforts were made to purify the 10-20 metric tons of liquid slurry produced, which was dispersed using a homemade sprayer, first from the roof of a cult building located in a residential neighborhood and later from a modified truck.
In the former case, some birds and neighborhood pets were apparently killed, though whether by the substance released remains unclear. Neighbors complained of the foul odor and gelatinous substance that rained down in the building’s vicinity, leading the police to visit and gather samples, but these were not tested until after the 1995 sarin subway attacks.  After attacks with liquid slurry failed to produce any casualties, the group began to employ crude drying devices to produce a powder, an unknown quantity of which was disseminated by truck in Tokyo. 
Although some neighborhood birds may have perished, it appears no humans were harmed as a result of Aum’s B. anthracis efforts. In fact, multiple cult members apparently inadvertently inhaled the material produced and subsequently reported no ill effects.  As with BoNT, a variety of factors appear to explain Aum’s lack of success. If the cult was indeed attempting to produce a virulent strain of B. anthracis using two vaccine strains, this remarkably ambitious effort unsurprisingly failed. Even in the unlikely event that the effort had been successful, the resulting strain might not have been sufficiently robust for subsequent production, storage, and dissemination. In the even more unlikely event that Aum had produced and successfully stored volumes of a virulent strain, it is possible that poor dissemination capabilities might have damaged the material or failed to aerosolize it so that sufficient quantities could be inhaled. For example, the cult employed a homemade nozzle that reportedly spouted rather than sprayed and dispersed material during the day, exposing it to UV radiation and thermal updrafts that would have reduced concentrations at ground level.  But the most plausible hypothesis remains that Aum failed to obtain a virulent strain of B. anthracis.
Learning from Aum’s Failed Efforts
Especially in light of the paucity of bioterrorism cases, Aum’s failed efforts to deploy effective biological weapons are a rich data point for assessing the threat and identifying policies to ameliorate it. Every case has its idiosyncrasies, and perhaps none quite so much as Aum, which really was “stranger than fiction.” But with that caveat in mind, the case does suggest three generalizations about the bioterrorism threat.
Putting the bioterrorism threat in perspective
Cult leader Asahara took a key lesson from his acolytes’ repeated failures to mount an effective biological weapons attack: American hyping of the bioterrorism threat was intended to mislead groups like his into pursuing this unproductive path in lieu of other, potentially more effective weapons.  Although to this observer it appears unlikely Washington’s public diplomacy efforts are quite so crafty (at least not intentionally so), Aum’s struggles do suggest that successful bioterrorism is more challenging than it is often portrayed.
Generalizations from one case should be taken with a grain of salt, all the more so when the case is as idiosyncratic as this one. But the cult brought to bear both some degree of relevant expertise and very substantial resources. The head of the biological weapons program had completed undergraduate studies in agricultural and veterinary medicine and conducted PhD studies in virology, albeit was not a microbiologist and lacked tacit knowledge regarding working with bacteria.  Another senior member was a medical doctor. As for resources, the cult possessed and was willing to spend millions of dollars on its unconventional weapons programs and constructed substantial infrastructure to support it.
The Aum case particularly highlights the importance of specialized, tacit knowledge to be able to isolate, manipulate, cultivate, and sustain living organisms, somewhat in contrast to chemical weapons development efforts.  The cult’s failure to successfully deploy biological weapons appears to be over determined. Whatever the causes of its failures—and these remain somewhat ambiguous—it appears that plenty of others stood between the cult and a successful bioterrorism attack. For example, the cult appears to have failed to obtain a pathogenic strain of B. anthracis or a toxigenic strain of C. botulinum. But had it succeeded, it appears likely the cult would have struggled to cultivate those strains. Had it overcome that hurdle, cult members would almost certainly have exposed themselves during the production and dissemination process. Had they avoided those hurdles, Aum’s crude production and dissemination techniques would have meant that few if any non-cult members would have been sickened by the crudely disseminated slurry, even if it had contained BoNT or a virulent strain of B. anthracis.
Effective dispersal is a significant hurdle
Discussions of bioterrorism tend to focus on the possibility that individuals or groups might obtain agents they could use to conduct attacks, but often give short shrift to how readily such agents could be disseminated if they were obtained. The evidence suggests that Aum likely failed to obtain potent agents, and that its struggles to distribute what it did obtain effectively are therefore not necessary to explaining its failure to cause harm via biological weapons.
Nonetheless, Aum’s struggles to effectively disseminate the material it produced highlight an important finding. Obtaining agents is likely the greatest hurdle to successful bioterrorism, but disseminating them to cause large numbers of casualties, and simultaneously avoiding exposure of those doing the disseminating, is a non-trivial secondary challenge that popular discussions of bioterrorism often overlook.
Where there is smoke, there may later be fire
Aum’s efforts were characterized by steadily escalating levels of attempted violence, a relatively seamless transition from individual to mass attacks, and from conventional to unconventional weapons, and a trial-and-error process of repeated errors but persistence and attempts at correction in the face of failure.
Like other non-state groups, Aum engaged in steadily escalating levels of illegal action and violence. The group began with the illegal disposal of the body of a cult member who had been accidentally killed and escalated to attacks on individuals perceived to be antagonistic to the cult and ultimately the general populace. Initial transgressions appear to have cemented group affiliation, emboldened cult members and especially the leader Asahara, and made it difficult for members to back out as violence escalated.
One striking element of the case is the relatively seamless transition from individual to mass attacks, and from more to less conventional ones, (i.e., from killing a lapsed cult member by strangling him with a rope to attempting to expose large populations to BoNT and B. anthracis). Normative inhibitions appear to have played little role, although it is hard to know how far that can be generalized beyond the case.
Relatedly, the cult was not dissuaded by repeated failures, and it was emboldened at the lack of consequences for its earlier actions. This suggests that where there is smoke there may be fire, in other words, failed attacks may be harbingers of future, and potentially more successful, ones. The pattern of trial, error, and potential later success also provides support for a “broken windows” theory of counterterrorism: responding robustly to more modest initial transgressions may make subsequent greater transgressions less likely. 
 Philipp C. Bleek is assistant professor of Nonproliferation and Terrorism Studies in the Graduate School of International Policy and Management at the Monterey Institute of International Studies, a Graduate School of Middlebury College, and fellow at the James Martin Center for Nonproliferation Studies. He thanks Richard Danzig, Jessica Varnum, and Ray Zilinskas for helpful comments on earlier drafts.
 One striking thing about Breivik’s manifesto is the sobriety of its analysis of anthrax, especially given the author’s apparent lack of relevant expertise. However, since much of the manuscript was plagiarized from various sources, whether Breivik deserves much credit for the analysis is debatable. “Theoretically,” the manifesto says (in this case channeling Wikipedia), “anthrax spores can be cultivated with minimal special equipment and less than a first-year collegiate microbiological education.” But in practice, the document notes, the procedure “is difficult and dangerous.” Andrew Berwick (pseudonym), 2083: A European Declaration of Independence (self-published, 2011), accessed November 4, 2011 at https://www.kevinislaughter.com/wp-content/uploads/2083+-+A+European+Declaration+of+Independence.pdf, pp. 952-954, 957, 959, 961-965.
 As William Rosenau notes, “Aum is the only example of a terrorist group that has attempted to carry out mass murder with biological toxins and human pathogens. Other terrorists have attempted to acquire human pathogens, and one religious cult has succeeded in poisoning food with dangerous bacteria. But to date only Aum has attempted to create and use bioweapons on a large scale. In short, Aum is an important source of empirical information on sophisticated terrorist efforts to acquire these weapons.” William Rosenau, “Aum Shinrikyo’s Biological Weapons Program: Why Did It Fail?” Studies in Conflict and Terrorism Volume 24, Number 4 (2001), p. 290.
 John Parachini wrote in 2005, “Aum’s research about biological weapons remains remarkably obscure in official, journalistic, and scholarly accounts…These activities warrant considerably more thorough examination than they have received thus far.” John Parachini, “Aum Shinrikyo,” in Brian Jackson et al., Aptitude for Destruction, Volume 2: Case Studies of Organizational Learning in Five Terrorist Groups (Santa Monica, CA: RAND, 2005), p. 19.
 Richard Danzig et al., Aum Shinrikyo: Insights Into How Terrorists Develop Biological and Chemical Weapons (Washington, DC: Center for a New American Security, 2011). Danzig’s prior work on the topic includes Richard J. Danzig, Rachel Kleinfeld, and Philipp C. Bleek, After an Attack: Preparing Citizens for Bioterrorism (Washington, DC: Center for a New American Security, 2007); Richard J. Danzig, A Policymaker’s Guide to Bioterrorism and What to Do About It (Washington, DC: National Defense University, 2009); Richard Danzig, Catastrophic Bioterrorism: What Is To Be Done? (Washington, DC: National Defense University, 2003). Subsequent references to “Danzig et al.” refer to the Aum Shinrikyo report.
 Aum appears to refer to the “ohm” sound yoga practitioners make; Asahara (then Matsumoto) called his yoga school Aum, Inc. Shinrikyo means teaching of truth. An earlier iteration of the group was called Aum Shinsen no Kai, or Aum Mountain Hermit’s Society, based on a prophecy that survivors of the coming apocalypse would be benevolent shinsen, or mountain hermits. Ian Reader, Religious Violence in Contemporary Japan: The Case of Aum Shinrikyo (Honolulu: University of Hawaii Press, 2000), p. 89.
 Reader, pp. 63, 92. Only a modest fraction of these were “monks” or “nuns” who had fully rejected all ties to the outside world. The group also attempted to open branches in Germany, the United States, and Sri Lanka, and was apparently most successful in Russia, where it attracted approximately tens of thousands of followers after Asahara visited the country with several hundred Japanese members on a “Salvation Tour,” including “spectacular” events and considerable radio and television advertising. Parachini, pp. 29-31.
 Appendix C: Aum Shinrikyo Facilities in Global Proliferation of Weapons of Mass Destruction: A Case Study on the Aum Shinrikyo Senate Government Affairs Permanent Subcommittee on Investigations, October 31, 1995, accessed November 4, 2011 at www.fas.org/irp/congress/1995_rpt/aum/index.html.
 Reader, pp. 88-93. Although the cult’s often-inept violence attracted police attention, a combination of equally-inept policing and strict laws protecting religious organizations allowed it to act with relative impunity.
 Reader pp. 143-145, 148-151; Danzig et al., pp. 9, 12, 14.
 Reader, pp. 148, 153-158.
 Reader, p. 180.
 Robert Jay Lifton, Destroying the World to Save It: Aum Shinrikyo, Apocalytic Violence, and the New Global Terrorism (New York: Metropolitan Books, 1999), pp. 119-120. One can imagine the elderly archivist’s bafflement at the strange Japanese visitors who spent day after day digging through the archives for earthquake generation-related material.
 Parachini, p. 23
 Parachini, p. 26; Reader, p. 217; Lifton, p. 181.
 Danzig et al., p. 29.
 The Danzig et al. study also includes a rich account of Aum’s chemical weapons efforts with some new details about the cult’s activities, including the most thorough discussion of the cult’s crude but effective sarin dissemination techniques published to date.
 Danzig et al., p. 16.
 Since the cult operated a hospital, it could plausibly have obtained the bacterium from a commercial culture collection.
 What was gathered remains unclear, but a key cult member told Danzig et al. that the cult worked on at least five strains or variants of C. butulinum, although some material may later have been obtained from a South American culture collection. How the cult isolated and identified the strains on which it supposedly worked remains unclear. Danzig et al., p. 16.
 The Danzig et al. study notes this possibility but does not attribute it to a source; see endnote 68, p. 54.
 Danzig et al, p. 16.
 Danzig et al., p. 17.
 A key cult member described to Danzig et al. two or three cube-shaped steel boxes, with dimensions of 2 x 2 x 2.5 meters, used as fermenters, and approximately 50 batches of yellow liquid produced. The total volume supposedly produced would be sufficient to fill dozens of full-size fertilizer transport trucks, suggesting that perhaps the cult member’s recollections should be taken with a grain of salt. That said, Aum had both very substantial financial resources (a study by the U.S. Senate Government Affairs Permanent Subcommittee on Investigations estimated Aum’s total resources in 1995 at more than $1 billion), and the land and manpower for substantial facilities. Global Proliferation of Weapons of Mass Destruction: A Case Study on the Aum Shinrikyo, Senate Government Affairs Permanent Subcommittee on Investigations, October 31, 1995, accessed November 4, 2011 at www.fas.org/irp/congress/1995_rpt/aum/index.html.
 Mice were apparently injected with the yellow liquid; whether ingestion and aerosol inhalation were also employed is unclear. There appears to have been some uncertainty about whether some mice were affected; some did die, but it was unclear whether this was linked to the administration of the botulinum. Danzig, p. 16 and endnote 76, pp. 54-55.
 Danzig et al., p. 17.
 Danzig et al., pp. 17, 20.
 Danzig et al., p. 21.
 W. Seth Carus, Bioterrorism and Biocrimes: The Illicit Use of Biological Agents Since 1990 (National Defense University, 2002), p. 50; Gregory D. Koblentz, Living Weapons: Biological Warfare and International Security (Ithaca, NY: Cornell University Press, 2011), p. 213; Milton Leitenberg, Assessing the Biological Weapons and Bioterrorism Threat (U.S. Army War College, 2005), p. 60.
 Danzig et al., p. 17.
 Danzig et al, pp. 20-21.
 Some of the uncertainty stems from the fact that the individual in charge of the cult’s biological weapons efforts declined interview requests from Danzig et al., and other key cult members disclaim knowledge of his bacillus anthracis source(s). Danzig et al., pp. 21, 23.
 Parachini, p. 21.
 Unfortunately, the cult member in charge of the biological weapons program declined to meet with Danzig and his colleagues.
 Paul Keim, who with colleagues had analyzed a sample from Aum’s 1993 attempted B. anthracis attack and identified it as a benign Sterne vaccine strain, conducted further analysis in 2010 in response to a request from Danzig et al. and determined that, “The genome sequence was extremely similar not just to Sterne but specifically to the 34F2 strain then available at Obihiro,” the university where the cult member in charge of the biological weapons program had conducted his undergraduate studies. Danzig et al., p. 23.
 Virulent B. anthracis possesses two plasmids, while the Sterne and Pasteur strains each possess only one of the two and can consequently stimulate immune reactions without being lethal. The two strains can be employed to yield virulent bacteria via either cell-to-cell “mating” (conjugation), or the use of a virus that infects bacteria (transduction). The technique is challenging and likely beyond the abilities of Aum’s members, but Danzig et al.’s speculation that it was being attempted finds considerable support from the accounts of cult members and other information. Danzig et al, pp. 23-25.
 The speculation is further reinforced by the recollection of one key cult member that a microscope was used to confirm success in transforming the vaccine strain to a more virulent one. The second plasmid found on a virulent anthrax strain generates a capsule that can be viewed after staining under a light microscope. Danzig et al, p. 24. The Russian paper cited is A.S. Stepanov, “Transduction and Conjugation Transfer of the pX02 Plasmid in Bacillus anthracis” Molekuliarnaia Genetika, Mikrobiologia, I Virusologia 12 (1989), pp. 39-43.
 Raymond A. Zilinskas, Biological Warfare: Modern Offense and Defense (Lynne Rienner, 2000), p. 81; Lifton, p. 188; Danzig, p. 25.
 Danzig et al., p. 25.
 Danzig et al., p. 25.
 Gregory D. Koblentz, Living Weapons: Biological Warfare and International Security (Ithaca, NY: Cornell University Press, 2011), p. 213.
 Danzig et al., p. 26, based on Danzig interview with Fumihiro Joyu, April 21, 2008. One can imagine Al Qaeda operatives similarly grumbling about chemical, biological, and especially nuclear terrorism risk assessments; the online humor magazine The Onion nicely captured that scenario in a story headlined “Terrorist Has No Idea What To Do With All This Plutonium” a few years ago. November 30, 2005, accessed October 2, 2011 at www.theonion.com/articles/terrorist-has-no-idea-what-to-do-with-all-this-plu,1847/.
 Tacit knowledge is knowledge that cannot be conveyed in words or symbols, but must be learned by doing, often through a process of trial-and-error. A paradigmatic example is learning to write a bicycle; a textbook on bicycle-riding would presumably be of little use to mastering the core skill of balancing while operating the bicycle.
 Successfully mounting a B. anthracis attack requires skills associated with obtaining, growing, processing, sporulating, drying, pulverizing, testing, and disseminating, posing major challenges even for those trained as, for example, medical doctors or veterinarians.
 The “broken windows” strategy of policing was first articulated by James Q. Wilson and George L. Kelling in a 1982 article in the Atlantic Monthly, in which they suggested that not fixing broken windows would encourage greater transgressions. The approach was famously implemented in New York in the early 1990s, first by the head of the city’s Transit Police, William Bratton, and then by Major Rudy Giuliani and his police commissioner, Howard Safir. As implemented in New York, one notable example of “broken windows” were the “squeegee men” who cleaned car windshields at intersections and then demanded payment. James Q. Wilson and George L. Kelling, “Broken Windows: The Police and Neighborhood Safety” The Atlantic Magazine (March 1982), accessed November 4, 2011 at https://www.theatlantic.com/magazine/archive/1982/03/broken-windows/4465/.