Tactical Diversity in Militant Violence October 2015

Militant groups, like all organizations, face crucial decisions about the strategies that they employ. In this article, we assess why some militant organizations successfully diversify into multiple tactics while others limit themselves to just one or a few. This is an important puzzle because militants with increasingly diversified tactics are more likely to stretch counterterrorist defenses, achieve tactical success, and threaten state security. We theorize that government repression and inter-organizational competition put pressure on militants and incentivize groups to diversify their tactical portfolios in order to ensure their survival and continued relevance. The results from empirically analyzing multiple datasets show robust support for our theory. To address the possible endogeneity of repression and diversification we then confirm these findings in a more fully identified specification that employs ethnic fractionalization as an instrument in a multi-process recursive model. Finally, we demonstrate that organizations that diversify under pressure adopt more disruptive tactics such as hijacking and suicide bombing, rather than devolving into less threating approaches such as isolated shootings and kidnappings. The policy implication is that while countries cannot anticipate the character of future tactical innovations, they may be able to anticipate which groups will most readily adopt them. “Tactical Diversity in Militant Violence” 2 Mao Zedong (1963, p. 245) advised that militant leaders “should know not only how to employ tactics but how to vary them,” because this would allow irregulars to surprise better equipped state forces, keep them on their heels, and eventually overcome their defenses. Mao is far from alone in this emphasis on tactical diversity: the writings and practices of leaders as disparate as Sun Tzu and Osama bin Laden stress the benefits of variety in the use of force. Non-state actors in particular rely on tactical diversity to reduce the predictability of their actions, thereby spreading state defensive capabilities thin. Tactical diversity is therefore a key component of an effective strategy in asymmetric conflict because it helps to overcome disadvantages in terms of resources and manpower. This echoes counterterrorist and counterinsurgent policymakers who see expansive tactical repertoires as a serious impediment to a successful state response (Paquette 2010, 33). Prominent cases from the terrorism literature bolster the notion that diversification is disruptive to states and beneficial to militants. The Popular Front for the Liberation of Palestine (PFLP), for example, bedeviled Israeli counterterrorism efforts for decades by consistently expanding their tactical portfolio. By altering their mix of (and approaches to) hijackings, kidnappings, assassinations, and bombings they complicated Israeli counterterrorism efforts, while simultaneously keeping militant rivals and their political audience guessing. Indeed, the “innovative tactical approach employed by the PFLP and its offshoots...[made] international terrorism a permanent and significant factor on the international stage, and whose tactics were copied by Palestinian and other groups for years to come (Schweitzer 2011, 27).” Among scholars, however, the question of tactical diversity has fallen by the wayside. What work there is (e.g. Moghadam 2013), primarily focuses on the related “Tactical Diversity in Militant Violence” 3 question of innovation, rather than diversification per se. Others focus on particularly disruptive tactics in isolation. Examples include suicide bombing (e.g. Atran 2003; Pedahzur 2005), improvised explosive devices (e.g. Ackerman 2008; Barker 2011), aerial hijacking (e.g. Dugan et al. 2005), kidnapping (e.g. Brandt and Sandler 2009), and WMD terrorism (e.g. Ackerman 2005; Blum et al. 2005). Little attention, however, is given to the extent to which organizations use tactics in combination. In response to this shortcoming, we explore the conditions under which organizations adopt and employ diverse portfolios of tactical capabilities. Despite the apparent benefits of broad tactical expertise, variation within the level of diversification across groups suggests that it is not universally desirable. Indeed, not all organizations diversify even if they have the resources to do so. For example, the Weather Underground, Euskadi Ta Askatasuna (ETA), and the Red Army Faction all limited the number of tactics that they employed, preferring tried and true methods of violence to the uncertainty of experimentation and diversification. This reticence suggests that, despite the apparent advantages, tactical diversification comes with costs and risks that some groups lack the incentive to incur. Why then do some organizations employ many tactics while others rely on one or a few? We argue that militant groups diversify when their organizational viability is threatened, overshadowing the costs of expansion and amplifying the need for tactical successes. We focus on the two preeminent threats to organizational survival: from the state and from competitors. In the face of substantial repression from the state, militants rely on tactical expansion to circumvent counterterrorism measures, improve their success rate, and ultimately ensure their continued relevance. Similarly, when faced with rivals – “Tactical Diversity in Militant Violence” 4 and particularly very capable rivals – groups will tactically expand as a means of signaling their own strength and resolve in order to maintain the appeal to local populations thereby ensuring their continued access to resources and recruits. We test these arguments in the context of both the Global Terrorism Database (GTD) and Minorities at Risk Organizational Behavior (MAROB) datasets, finding clear evidence that both state repression and intergroup competition lead to tactical diversification. To address the potential endogeneity between repression and tactical diversification we confirm these findings using a multi process instrumental variable model in which we rely on ethnic fractionalization as an excludable indicator associated with repression but not tactical diversity. Finally, we then consider the consequences of diversification to understand whether organizations escalate into more sophisticated and lethal tactics or devolve into myriad low-tech approaches. The results are consistent with our theory, showing that organizations that diversify tend to escalate upwards into more advanced options like suicide bombings and coordinated attacks, but they also tend to inflict more casualties and strike a greater proportion of “hard” targets. When groups tactically contract, the trend reverses and groups become significantly less likely to use sophisticated methods against hard targets. The results have significant implications for our understanding of subnational political violence. We find a meaningful relationship between organizational duress (in the form of both state repression and inter-organizational competition) and tactical diversification and, through this mechanism, the escalation of violence. When it comes to 1 This logic draws explicitly on the outbidding mechanisms described by Bloom (2005) Kydd & Walter (2006), and others. “Tactical Diversity in Militant Violence” 5 competition, our findings provide some support for longstanding arguments about “outbidding” as a factor motivating the adoption of high-profile tactics such as suicide bombing (Kydd and Walter 2006; Bloom 2004; Findley and Young 2012). From a counterterrorist perspective, however, the conclusion is disquieting – cracking down on organizations, if they are able to diversify, can lead to a spiral of bloodshed. Understanding Diversification For many organizations the logic of diversification is rather intuitive: as the saying goes, it is unwise to “put all your eggs in one basket.” When operating in an environment of uncertainty and danger, strategically minded actors reduce their exposure to risk by avoiding reliance on a single strategy. That said, while diversification should be employed preemptively as a hedge against risk and uncertainty, it is more commonly a post hoc response to external challenges and setbacks (March and Simon 1958; Romanelli and Tushman 1994). Research shows that firms, for example, expand their strategies in response to external pressures and competition (Lawrence and Lorsch 1967; DiMaggio and Powell 1991; March and Simon 1958; Thompson 1967). As Chakrabarati (2014) notes in the context of firm responses to the recent financial crisis, the more extensively and rapidly that environments change, the more that organizations need to adapt to survive. In such environments, shocks and disruptions become stimuli for diversification and other forms of 2 Many readers will rightly think of diversification in terms of financial planning, where the same basic logic holds. (see, for example, Markowitz 1968). It is economic orthodoxy that investment portfolios with diverse combinations of stocks and bonds are more likely to achieve stable, long-term gains than bets on a single industry or company (Goetzmann and Kumar 2008). “Tactical Diversity in Militant Violence” 6 risk taking as firms seek out strategies to mitigate such occurrences in the future (McNamara and Bromiley 1999; Weitzel and Jonsson 1989). Of course, militant groups are not firms, but there are theoretically useful parallels. At the most basic level these are both organizations seeking success in competitive environments, and scholars can make inferences particularly by drawing on the basic nature of group behavior. Indeed, a substantial and growing portion of the terrorism literature establishes the commonalities between firms and militant organizations and then draws on them to generate theoretical expectations that find empirical support (e.g. Crenshaw 1987; Shapiro 2013; Abrahms and Potter 2015). If, however, these conceptual analogies are not theoretically useful the proof will be in the results – since hypotheses drawn from those analogies will find support in the data. Perhaps more analogous to militant groups are state militaries that value diversification for very similar reasons. Interest by militaries in diversification goes back at least to Sun Tzu, who writes “...when I have won a victory I do not repeat my tactics but respond to circumstances in an infinite variety of ways (Sun Tzu 1963, 65).” Unpredictability places pressure on ones adversaries, increasing confusion and making them more likely to commit mistakes (Levy 1983). Furthermore, diversified military power contributes to victory in war “because the state gains flexibility when it mixes instruments of power in varying combinations: it can thereby choose the best instrument(s) for the particular conditions faced and the level of victory sought (Martel 2011, 288).” The emphasis on diversification extends to the realm of nuclear security as well. Historically, states have sought to strengthen their nuclear deterrent by deploying weapons in multiple locations and by utilizing an array of delivery vehicles (Freedman 1981, 326). “Tactical Diversity in Militant Violence” 7 This is precisely why the United States developed a nuclear triad (nuclear-armed bombers, nuclear-armed submarines, and land-based nuclear-armed missiles) as a means of ensuring second-strike capability. Notably, this enormous investment occurred in the context of a pronounced rivalry with the Soviet Union (Schwartz 1998). Nonetheless, not all organizations diversify tactically. A major reason for this is that diversification is neither simple nor cheap. Research on firms, for example, shows that needless diversification can distract from core competencies (Raghuram, Servaes, and Zingales 2000). Militant organizations develop tactical experience over time and diversification can divert resources away from these developed abilities that have a higher probability of operational success. In addition, tactical diversification ultimately requires organizations to take risks, spending resources on an uncertain outcome. Diversification can prove unsuccessful if the new ability is never fully mastered or if the population does not approve. Ultimately, this suggests that militant groups sometimes face incentives to stick to the status quo, utilizing existing tactical options that they have already mastered rather than branching out towards new and uncertain abilities. Together, these examples underscore the general logic behind diversification: it increases flexibility, unpredictability, and complicates adversary calculations. Yet embracing diversification is risky and it requires resources that can tax an organization while simultaneously distracting from developed capabilities. As a result, organizations generally pursue diversification when the operating environment presents new challenges that tip the ratio of risk and rewards, incentivizing experimentation over complacency. In the next section, we consider how these ideas translate to militant organizations. “Tactical Diversity in Militant Violence” 8 Terrorism and the Incentives for Diversification How do these advantages and costs translate to case of militant groups? Although the process works through multiple mechanisms, tactical diversification ultimately undercuts and challenges defensive counterterrorism, creates new vulnerabilities, and raises the likelihood of attack success (Paquette 2010). First, diversification expands the number of targets that a state must defend and the ways in which it must defend them. According to Wilkinson (2014, 204) “...the key components of the counter-terrorism strategy must be geared to the type of terrorist threat confronted.” If militant organizations make predictable and limited tactical choices then governments can design their defensive efforts for fewer and more specific modes of attack (Stevenson 2001), but diversification undercuts this sort of specialization. The British government, for instance, was able to focus its operations on remotely detonated explosives and armed assaults because they were relatively unconcerned by the possibility of IRA suicide operations or aerial hijackings (Secretary of State for the Home Department 2011). More varied threats require a complex and costly response and the corresponding rebalancing of resources is a difficult task, requiring coordination and effective communication between different agencies at both local and federal level (Bergen et al. 2010, 31). Second, if tactical diversity successfully stretches defenses and forces states to prepare for a broader range of possible attacks, it can ultimately introduce new vulnerabilities that militants can then exploit. As Crenshaw notes, “The purpose of innovation in terrorism is to maintain the possibility of surprise because it is critical to success (Crenshaw 1987, 15).” Since all objective measures of strength and power tend to “Tactical Diversity in Militant Violence” 9 favor states, this element of unpredictability is ultimately what allows terrorist attacks to succeed. Moreover, for many states, defensive spending is essentially zero-sum because counterterrorism budgets are at least somewhat fixed, with state decisions centered on how to allocate funds to defend possible targets based on expectations about different types of attack (Faria and Arce M 2005; Golany et al. 2009; Rosendorff and Sandler 2004). As a result, tactical diversification can force states to apportion their defensive resources more broadly. Combined, reapportioning fixed budgets and the uncertainty of new defenses can create avenues for militants to exploit as states simply cannot defend every asset equally well, which ultimately increases the likelihood of successful attacks. Third, tactical diversification enables militants to overcome or circumvent defensive innovations. Wilkinson and Jenkins (2013, 24) find that “the history of attacks on aviation is the chronicle of a cat-and-mouse game, where the cat is blocking old holes and the mouse always succeeds in finding new ones.” Consider groups that specialized exclusively in either hijacking or remotely detonated bombs, both of which were largely nullified as viable tactics by technological and procedural adaptations by states. Metal detectors brought about a drastic drop in the success rate of aerial hijacking (Im et al. 1987; Dugan et al. 2005), while authorities can now quickly screen for radio transmissions that suggest the presence of a remotely-detonated explosive (Hoffman 1993). Groups with a diverse tactical arsenal can alter their operational profiles to outpace such changes in the defensive environment. This can manifest as a major innovation in response to initiatives like metal detectors, but also as more subtle adjustments to smaller changes in the defensive environment to take advantage of temporary or emerging vulnerabilities. For a terrorist attack to succeed, there needs to be a match between the organization’s tactical “Tactical Diversity in Militant Violence” 10 capabilities and the operational requirements of the attack – more tactical capabilities mean that more operations are potentially on the table (Jackson and Frelinger 2009). The tactical success that arises from diversification contributes to organizations’ core long-term objectives: survival and strategic success. Blomberg et al (2010, 18) find that “the level of violence perpetrated by an organization...suggests that success breeds survival.” Success can also translate into organizational strength by inspiring support among the population (Paul 2009, 113). Given these benefits, it should come as no surprise that diversification is also associated with strategic success since militants with diverse tactical portfolios allow organizations to impose more costs on their adversaries. There is clear empirical support for the association between diversification and favorable political outcomes. For example, as indicated in Figure 1, among the 181 militant organizations that achieved formal talks with the government (as identified by Cronin (2009)), the average number of tactics employed is 4.6. However, for unsuccessful groups, the average number of tactics is only 3 (p<0.001). A similar pattern emerges among groups that did and did not reach their strategic goals, with the latter employing 4.1 tactics compared to 3.2 for their less successful counterparts (p=.056). Ultimately, groups wielding a broader tactical arsenal achieve somewhat greater success. 3 If the threshold is raised to successful talks, then the difference is increases slightly to 4.75 and 3 tactics for successful and unsuccessful groups, respectively. “Tactical Diversity in Militant Violence” 11 Figure 1: Relationship between Terrorist Success and Tactical Diversity Data from Cronin (2009) The factors that impede diversification in other fields likewise exert an influence on militant groups. Indeed, many organizations with extensive capabilities and resources do not draw on these advantages to diversify their tactical arsenal. This tendency arises from a logical bias toward the status quo. As we have noted, research on organizational behavior finds that groups most commonly diversify tactics and strategies in response to substantial external pressure (DiMaggio and Powell 1983; DiMaggio and Powell 1991). Lacking this pressure, terrorist groups have little motivation to expend resources to institute internal changes, particularly if those changes might expose them to risk (Shapiro 2013; Horowitz 2010b). The risks associated with diversification can be substantial. A less focused group with an overly broad agenda and resources that are spread thin is less likely to recruit new 4 Cronin identifies a number of strategic goals. Government negotiation indicates that a group achieved formal, strategic negotiations with the government, even if they ultimately failed; non-failed government negotiations means that formal, strategic negotiations took place that were not formally abandoned; and finally, some strategic success refers to whether or not any level of a group’s strategic objectives were ultimately met. 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 Government Nego3a3on Strategic Success Ta c$ cs Successful Groups Unsuccessful Groups “Tactical Diversity in Militant Violence” 12 members and maintain the ones that it has, leading to splits within the organization. Jemaah Islamiyya and Tanzim Qaedat al-Jihad, for example, splintered around 2003 over the use of suicide bombing and whether more resources should be devoted to religious and civilian outreach or indiscriminate violent attacks (Surrette 2009; Magouirk et al. 2008). Moving into less tried and true tactics also introduces the risk of failed missions that can cast a positive light on state counterterrorism efforts, making terrorists appear less threatening to the civilians they target and driving down their support among those they seek to win to their political cause. The central objective of militant organizations, and arguably any organization, is survival (Wilson 1989; Olson 1982; Olsen and March 1989). Adaptation occurs primarily when it bolsters survival and is curtailed when it puts it at risk (DiMaggio and Powell 1983; Levinthal 1991). Thus, militant organizations diversify their tactics when circumstances force them to adapt – a process that has direct parallels in the way that existential threats incentivize tactical innovation in national militaries (Posen 1984, 1993), In contrast, organizations in less precarious positions rely on patterns and routines that have worked in the past; for them, change introduces an element of risk and uncertainty that is not worth the cost. Although militant groups strive for their political objectives it is rarely at the expense of their organizational viability. Consequently, groups will overcome the barriers to diversification when they face a mix of pressures and incentives that force them to do so. Two sets of incentives appear critical for tipping the calculus away from the status quo and towards tactical expansion: state repression and group competition. “Tactical Diversity in Militant Violence”