Leadership targeting has become a key feature of counterterrorism policy. Both academics and policymakers have argued that the removal of leaders is an effective strategy in combating terrorism. Leadership decapitation is not always successful, however, and existing empirical work does not account for this variability. A theory of organizational resilience explains why decapitation results in the decline of some terrorist organizations and the survival of others. Organizational resilience is dependent on two variables: bureaucratization and communal support. Older and larger organizations tend to develop bureaucratic features, facilitating a clear succession process and increasing their stability and ability to withstand attacks on their leadership. Communal support plays an important role in providing the resources necessary for terrorist groups to function and survive. Religious and separatist groups typically enjoy a high degree of support from the communities in which they operate, and thus access to critical resources. Application of this theoretical model to the case of al-Qaida reveals that Osama bin Laden's death and the subsequent targeting of other high-level al-Qaida operatives are unlikely to produce significant organizational decline.

Does leadership decapitation lead to the demise of terrorist organizations? Can the United States undermine or destroy terrorist organizations such as al-Qaida by arresting or killing their leaders? What explains organizational resilience to leadership targeting? Leadership decapitation, or the killing or capturing of the leaders of terrorist organizations, has become a core feature of U.S. counterterrorism policy. Many scholars and analysts claim that it weakens terrorist organizations and reduces the threat they pose. Unsurprisingly, they saw the killing of Osama bin Laden on May 2, 2011, in Abbottabad, Pakistan, as a major tactical victory for President Barak Obama and for the broader war on terrorism. Despite the success of this operation and subsequent attacks on al-Qaida leaders, decapitation is unlikely to diminish the ability of al-Qaida to continue its activities in the long run. Rather, it may have counterproductive consequences, emboldening or strengthening the organization.

Since the terrorist attacks of September 11, 2001, the United States has killed or captured many al-Qaida leaders as part of a general campaign to decapitate the organization. It has employed a variety of military operations to achieve this objective, including raids by Special Operations forces. Both bin Laden and Abu Musab al-Zarqawi, leader of al-Qaida in Iraq, were killed as a result of such raids. On October 5, 2012, U.S. forces captured Abu Anas al-Libi, an al-Qaida leader, in a raid in Libya. The United States has also relied heavily on drone strikes to target al-Qaida leaders and other militants in Afghanistan, Pakistan, and Yemen.

In June 2012, Abu Yahya al-Libi, then al-Qaida's deputy leader, was killed in Pakistan in a drone strike coordinated by the Central Intelligence Agency.1 Highly experienced, al-Libi served an important operational function within the organization. Scholars and policymakers saw his death as a significant blow to an already weakened al-Qaida.2 Nine months earlier, a Hellfire missile fired from a U.S. drone killed Anwar al-Awlaki, a Yemeni-American cleric linked to a number of terrorist plots in the West. On August 22, 2011, Atiyah Abd al-Rahman, believed to be the organization's second-highest leader, was reportedly killed in a drone strike in Pakistan.3 Rahman served an important communicative function between bin Laden and lower-level operatives. Ilyas Kashmiri, reputed to be a senior member of al-Qaida and the operational commander for Harakat-ul-Jihad al-Islami, was killed in a drone attack in South Waziristan on June 3, 2011.4 These examples illustrate the frequency with which the United States has targeted al-Qaida leaders and operatives over the past few years, specifically through the use of drone strikes.5

Despite these and other instances of successful targeting, al-Qaida remains a resilient terrorist organization. Applying a theory of organizational resilience, I examine why targeting al-Qaida's leadership is not an effective counterterrorism strategy and, indeed, is likely counterproductive. A terrorist group's ability to withstand attacks is a function of two factors: bureaucratization and communal support. Analyzing both when and why certain terrorist groups are able to survive leadership attacks, this article differs from existing work by providing a more nuanced lens through which to evaluate the effectiveness of counterterrorism policy.

The analysis proceeds as follows. First, I discuss existing studies on the effectiveness of targeting terrorist leaders. Second, I present a theory of organization resilience to leadership decapitation. Third, I apply the theory to the case of al-Qaida. Fourth, I assess empirical evidence on the effectiveness of targeting al-Qaida. I then discuss implications of these finding for U.S. counterterrorism policy.

The literature on the effectiveness of leadership targeting focuses on five areas: the role of leadership, intelligence, and organizational structure, as well as quantitative findings and counterproductive consequences. First, much of the optimism surrounding the removal of terrorist leaders is grounded in theories that analyze the role of these leaders within their organizations. Theories of charismatic leadership, for example, posit that the susceptibility of terrorist organizations to leadership targeting is a function of qualities inherent to the leader.6 These qualities not only sustain leaders’ legitimacy, but also foster the belief among followers that such leaders are irreplaceable.7 Theories of charismatic leadership, however, overpredict the success of leadership decapitation while overlooking both organizational variables and social context.

Other studies examine the contribution of leaders to organizational strength and cohesion. According to Bryan Price, terrorist groups are clandestine, values-based organizations, making leadership succession difficult.8 Violent organizations are more cohesive and are often led by charismatic leaders, making succession especially difficult. Clandestine organizations are more dependent than nonclandestine organizations on their leaders, who are unlikely to institutionalize their operations for both strategic and personal reasons, further complicating succession. Finally, because terrorist organizations are values based, leaders are harder to replace, and their removal can cause instability. Price offers one of the few theoretical explanations for leadership decapitation, but his model does not account for variation in the effectiveness of leadership targeting. By treating all terrorist organizations as values based, his theory overpredicts the occurrence of success.

The role of the leader can be another predictor of the ability of a decapitation strike to weaken the organization. Michael Freeman argues that the likelihood of success in targeting leaders can be determined by whether they have an operational or inspirational role.9 Organizations in which the leader has both operational and inspirational roles are the most likely to collapse after decapitation. Freeman claims that although organizations with charismatic leaders tend to be susceptible to leadership attacks, over time they can become more institutionalized and more resilient in the face of such attacks.

Second, targeting operations can yield critical intelligence about terrorist group activity and lead to organizational weakening. For example, authorities found documents during the arrest of the leader of Peru's Shining Path, Abimael Guzmán, that led to the capture of other members of the group.10 Leaders under arrest can provide information about their organizations’ location, capabilities, personnel, and operations.11

Third, some studies have found a link between organizational structure and group stability.12 Kathleen Carley, among others, argues that decentralized organizations are harder to destabilize than hierarchical organizations.13 Marc Sageman claims that, given the structure of such organizations, leaders may not be the right targets. In a study of the global Salafi jihad, Sageman argues that social networks provide an opportunity for socially and geographically isolated and alienated individuals to join a community. The social bonds created within these communities create and strengthen the ideological commitment of potential militants, encouraging them to join jihadist movements. The decentralized and local nature of these groups makes them difficult to target.

Fourth, quantitative studies on leadership targeting yield different results regarding whether and when decapitation is effective. Price finds that decapitation increases the mortality rate of terrorist organizations. Patrick Johnston concludes that decapitation decreases the intensity and frequency of militant attacks, increases the chance of war termination, and raises the probability of government victory.14 Johnston claims that although decapitation can “help break the morale of insurgencies that have been engaged in long, often difficult campaigns,”15 it is more effective as part of a larger campaign. Although Johnston's statistical findings are robust, his article lacks a theoretical discussion of decapitation: it does not provide an explanation for why decapitation is effective, how it can influence a group's operational capacity, and when states should or should not target militant organizations. Furthermore, Johnston focuses exclusively on insurgencies. Although some terrorist groups are also insurgents, many insurgent organizations do not employ terrorist tactics.

Fifth, some studies argue that leadership targeting may be counterproductive. Unintended consequences include the creation of a martyrdom effect, a surge in recruitment, the occurrence of retaliatory attacks, an increase in group resolve and strength, and a rise in the frequency and intensity of attacks.

In this section, I present a theory to explain why some terrorist groups are able to survive attacks on their leadership and others are not. “Organizational resilience” refers to whether a group that has experienced degradation can still engage in terrorist activity.16 Terrorist group resilience is a function of two variables: bureaucracy and popular support. Leadership decapitation is unlikely to result in the dissolution of groups that are highly bureaucratized or that have high levels of popular support because leaders matter less in these circumstances. Groups that are bureaucratic and have popular support are the hardest to destabilize through leadership targeting, and it in these cases that counterproductive outcomes are likely.

HOW BUREAUCRATIZATION INCREASES GROUP RESILIENCE

The theory of organizational resilience posits that the extent to which a terrorist organization is bureaucratized accounts for whether decapitation is likely to result in its demise. Bureaucratized terrorist groups are diversified, have a clear division of administrative responsibilities and functions, follow rules and procedures, and are thus more likely to withstand the sudden removal of a leader or leaders. Because smaller, younger, and more ideological organizations are less likely to be bureaucratized, they are more likely to succumb to attacks on their leadership.

Bureaucracies have universalistic rules that are critical when delegating responsibilities within an organization.17 Michael Crozier argues that “impersonal rules” create a kind of self-enforcing equilibrium by delimiting in great detail the function of every individual within the organization.18 These results prescribe the behavior to be followed in all possible events. According to Max Weber, the clear delineation of authority, rules, and functions makes bureaucracies the most efficient form of large-scale administration.19

BUREAUCRATIC STABILITY

Bureaucracies contain specific features that increase organizational stability and efficiency, making them more resilient to leadership attacks. First, they are characterized by organizational diversification, and they maintain a clear delineation between duties and power.20 As organizations become larger, more complex, and more specialized, they are likely to develop diversified functions that increase their stability. Peter Grinyer and Masoud Yasai-Ardekani find that an organization will become more diversified and structurally complex as its size increases.21 Organizational diversification, in turn, helps to create a reliable and diversified resource base, which is necessary to sustain terrorist group activities.22 David Veness claims that terrorist groups with diversified funding sources have higher survival rates.23 And in a discussion of older groups with functionally differentiated branches, Jodi Vittori argues that larger groups find it easier to obtain diversified funding resources.24

Second, bureaucracies establish rules and routines that can enhance organizational stability and efficiency.25 As Martha Feldman and Brian Pentland write, routines are “the primary means by which organizations accomplish much of what they do.”26 Barbara Levitt and James March argue that routines increase the capacity for organizational learning, which can in turn increase organizational capacity and efficiency.27 They also increase stability by making organizations capable of surviving leadership turnover. Organizations that do not establish routines will struggle until they are perceived as reliable and accountable by their members and by the communities in which they operate.28

Highly bureaucratic terrorist organizations are more likely to experience smooth leadership transitions. Thus the violent or sudden removal of a leader should be less destabilizing in hierarchical groups, which have clear succession processes. Moreover, the clear division of responsibilities found in such organizations allows them to continue functioning because each member has specific duties. Finally, rules and procedures make the organization much less dependent on the leadership. Because the group's operations are institutionalized, the sudden removal of a leader should not have lasting effects on the organizational capacity of a targeted group.

EVALUATING BUREAUCRACY AND TERRORIST ORGANIZATIONS

Like bureaucracies, many terrorist organizations are hierarchical: their authority comes from the top; they have an administrative staff; they follow rules and standard operating procedures; and they maintain functionally separate branches and infrastructure. Even clandestine organizations such as terrorist groups can organize themselves bureaucratically. For example, they may keep documents relating to their members, finances, and activities.29 Terrorist group documents can offer insight into the group's organizational structure. For instance, some terrorist groups keep rosters of individuals, their ranks within the organization, accounting information, and charts of the organization's structure. These documents offer evidence of institutionalized rules and operating procedures.

The existence of separate political, military, and social wings within a terrorist group can signal that it has become more complex and able to carry out separate and distinct functions. Hamas and the Liberation Tigers of Tamil Eelam offer two such examples. Through their social or political branches, terrorist organizations often provide social services to the communities in which they are based. This is an important means by which they acquire support. Efficient infrastructure is necessary to effectively provide social services to local communities. As a result, the provision of services should signal that a group has developed a sufficient degree of bureaucratic control to manage this infrastructure. This infrastructure, in turn, can increase a group's resilience to targeting efforts.

Older and larger terrorist groups are more likely to have developed bureaucratic features, increasing their stability, effectiveness, and ability to survive an attack on their leadership.30 Arthur Stinchcombe's “liability of newness” thesis, which posits that a higher number of new organizations fail than old organizations, provides theoretical grounding for the hypothesis that older and larger groups should be more stable.31 Stinchcombe argues that as a group ages, it is likely to develop rules and routines that temper the costs associated with newness, decreasing the likelihood of organizational failure.32 Studies in business management have found that regardless of a group's initial organizational blueprint, age and size are positively correlated with bureaucracy.33

Because terrorist groups are by nature clandestine and under constant threat from counterterrorism measures, developing a stable bureaucracy presents challenges for groups that require secrecy.34 Still, many terrorist organizations, including the Shining Path and the Revolutionary Armed Forces of Colombia, have become highly bureaucratic. Some terrorist organizations, such as Hamas, are hierarchical at the upper levels, while maintaining decentralized networks at the operational level.35 These characteristics make many terrorist organizations exceedingly resilient to countermeasures.36

As mentioned earlier, much of the conventional wisdom regarding the effectiveness of leadership decapitation is based on theories of charismatic leadership. Even if terrorist groups depend on a charismatic claim to authority, charisma can become routinized, ultimately resulting in a bureaucratic form of authority. Routinization establishes norms and rules for recruitment, eliminating succession problems. The leader's message becomes institutionalized.37 Further, a routinized organization can provide for a group's needs by developing the economic conditions necessary to raise taxes and contributions. This point is fundamental for terrorist organizations, which must raise funds while remaining covert.

HOW POPULAR SUPPORT INCREASES GROUP RESILIENCE

Popular support is essential to a terrorist group's ability to maintain organizational strength and capacity following an attack on its leadership. Organizations with high levels of support have an easier time acquiring the resources necessary to carry out effective campaigns. Scholars including Roger Petersen and Scott Atran have argued that effective insurgencies require vast amounts of popular support.38 Militant organizations have recognized the importance of local community support.39 Groups with public support are likely to be seen as legitimate by their communities, further increasing their strength and effectiveness. As a result, counterinsurgency strategy has focused on winning “hearts and minds” to reduce the desire for rebellion. Underlying this approach is the idea that by addressing grievances, counterinsurgents will gain local support that could otherwise help insurgents.40 Because religious and separatist organizations often represent the views and beliefs of the community from which they emerge, they should have higher levels of communal support than ideological organizations, making ideological organizations easier to destabilize.

POPULAR SUPPORT AND STABILITY

Popular support contributes to terrorist group resolve and stability in many ways. It allows the group to recruit, raise money, provide critical resources, ensure its ability to operate as a covert organization, encourage more violent behavior, and maintain political and ideological relevance. First, supporters can provide useful information and be a source of recruits. Petersen suggests that the provision of resources, information, and recruits by the local community is key to understanding the success of rebellions.41 In a study examining terrorist organizations that carry out suicide attacks, Robert Pape argues that support can “enable a suicide terrorist group to replenish its membership.”42 Further, Atran claims that although reasons for communal support can differ, “without community support, terrorist organizations that depend on dense networks of ethnic and religious ties for information, recruitment, and survival cannot thrive.”43 Ultimately, communal support is critical for groups not only to succeed, but also to function.

Second, popular support can allow a terrorist group to function covertly by helping it avoid “detection, surveillance, and elimination by the security forces of the target society.”44 Because decapitation can generate a sense of outrage within the community, residents may respond to a targeted attack by offering a safe place in which a leader or key operatives can hide.

Third, public support for the use of violence can encourage terrorist groups to carry out more violent campaigns. Mia Bloom claims that when societies support the killing of civilians, terrorist groups have an incentive to adopt such tactics.45 In addition, terrorist organizations care about social approval and seek legitimacy to increase their status relative to rival militant groups. Risa Brooks argues that “the militant's home constituency forces militants to adhere to societal norms about how violence is used.”46 A society's tolerance for violence provides a group with physical security, intelligence, and defensive resources that can assist in concealing militants and in building infrastructure.47

Fourth, public support facilitates the ability of terrorist groups to maintain their political or ideological relevance. Local communities can lose interest in the ideology or aims of the group and thus undermine its cause,48 a phenomenon that explains the decline of many Marxist groups.49 The ideology on which religious and separatist groups is based does not depend on a particular group or leader for its articulation. A loss of public interest is therefore less detrimental to religious groups, whose ideology has appeal beyond the local community.

Fifth, local support is critical to the acquisition of resources that enable terrorist organizations to function.50 Resource mobilization theory can provide a way to understand how support and resources matter to a terrorist organization.51 Social movement organizations need resources to mobilize collective behavior to “sustain their activities and (perhaps) motivate people to contribute to their cause.”52 Groups with high levels of community support should be able to obtain more resources than those with less support. Mayer Zald and Roberta Ash posit that the environment of a social movement organization is composed of two elements: (1) the broader social movement, including the people who identify with it, and (2) the society in which the social movement operates. This constituent base determines the “ebb and flow of sentiments toward an organization” and is crucial for organizational success.53 And because its constituents control the size of a group's resource pool, the group with more community support should have a larger constituent base and thus larger resource flows.54Finally, political process theory, which attributes the success of social movements to political opportunity, further highlights the importance of public support to insurgencies. Noting that “indigenous structures frequently provide the organizational base out of which social movements emerge,” Doug McAdam identifies four resources that are critical for insurgent group activity: members, solidary incentives, communication networks, and leaders. These resources facilitate political action and ensure group survival, particularly in response to repression against the insurgent community.55

EVALUATING POPULAR SUPPORT FOR TERRORIST ORGANIZATIONS

Terrorist groups that provide social services to their local communities may experience increased public support, and thus a boost to their public image. Hamas's provision of social services to Palestinians living in the Gaza Strip and West Bank is a useful example.56 In creating local networks that have provided critical educational, social programs, and religious services, Hamas has established a well-organized, highly functioning infrastructure, allowing it to obtain resources for its political activities and to facilitate continued support.57 Organizations that provide social services are not only more resilient but also more effective.58

Second, a society's tolerance for violence can serve as an indicator of popular support. Heavy-handed counterterrorism tactics can increase public support for the terrorists’ cause. Bloom argues that the manner in which a state responds to terrorism will have an effect on whether suicide bombers can win the “hearts and minds” of the larger population.59 More generally, she argues that “some of the more heavy-handed counterterrorism tactics of certain states, such as preemptive attacks on the supporters of terrorism, are likely to backfire and mobilize greater support for terror.”60

Third, public opinion surveys are also useful in evaluating changes in support for terrorist organizations. Admittedly, there are obvious limitations to the use of public opinion data in this regard. In the case of al-Qaida, for example, there is a shortage of data in many of the countries in which the organization operates. A further problem is that most surveys do not collect data over time, making it difficult to identify how attitudes and support for al-Qaida and militancy may change. In addition, respondents may not feel comfortable or safe expressing their true feelings toward al-Qaida and militancy, in general. Still, trying to assess public opinion support for militancy can be useful, given its contribution to organizational resilience.

Some types of organizations generate more popular support than others. Indeed, organizational type can be a proxy for communal support. I argue that separatist and religious groups should have more support than ideological groups because it is easier for them to reproduce the doctrines on which their organizations are based.61 In comparison, the doctrines of ideological organizations usually depend on a set of beliefs exclusive to those groups, their leader, or a particular time period. For example, the Shining Path adhered to an interpretation of revolution grounded in Guzmán's extremely violent and uncompromising interpretation of Maoist beliefs.62 Other organizations tend to represent a minority view of the communities from which they emerged. These views are more often found on the fringe, making the role of individual leaders all the more necessary to promote the values and beliefs of the groups.

Although the tactics of terrorist groups can be more radical than what many communities would like, their beliefs often enjoy common support. Terrorist groups acting on behalf of separatist movements represent the desire of those communities to acquire some degree of autonomy or independence. Their ideology reflects the overall orientation of the communities from which those groups emerged and operate. As with religious organizations, this embeddedness provides separatist groups with a great deal of local support, making them more likely to be seen as legitimate in the communities within which they operate.63 Targeting policies can further increase local support for a terrorist organization, resulting in counterproductive consequences. The following section examines the interaction between bureaucracy and communal support as it pertains to organizational resilience and the possibility of retaliatory responses.

INTERACTION BETWEEN BUREAUCRACY AND COMMUNAL SUPPORT

Bureaucracy and communal support interact in multiple ways. Variation in organizational responses to decapitation is a function of variation in levels of bureaucracy and communal support. Terrorist organizations with high levels of both bureaucracy and communal support should be able to survive attacks on their leadership and carry out retaliatory attacks in response to decapitation (see figure 1, quadrant I).64 Leaders matter less in these cases, and it is easier for an organization to regroup and rebuild after having undergone such attacks. Organizations in quadrant II (high bureaucracy and low communal support) should also be able to survive attacks on their leadership, as should organizations in quadrant III (low bureaucracy and high communal support). There is an important difference between the two types of organizations, however. Organizations in quadrant II should find it easier to regroup and rebuild after experiencing a destabilizing leadership attack, whereas those in quadrant III should still survive, but are likely to have a harder time regrouping. Finally, if organizations have low levels of both bureaucracy and communal support (quadrant IV), they are likely to succumb to attacks on their leadership.

Figure 1.

Organizational Resilience to Leadership Decapitation

Figure 1.

Organizational Resilience to Leadership Decapitation

Bureaucracies require a supply of individuals who, after displaying organizational commitment and competence, can move up the organizational ranks. Volunteers and recruits often do not enter the organization with demonstrated competence. Those who display more commitment, passion, and expertise are able to climb the ranks. Terrorist organizations also fundamentally depend on the ability to recruit new members to fill positions occupied by militants who may have been captured or killed. A group with more communal support will be able to attract the recruits necessary for a group to regenerate. The next section examines data on leadership targeting.

EMPIRICAL FINDINGS ON LEADERSHIP DECAPITATION

To evaluate the effectiveness of leadership decapitation and identify the conditions under which decapitation is more or less likely to result in organizational decline, I created a dataset of 298 instances in which terrorist leaders from 92 terrorist organizations were arrested or killed from 1945 to 2004.65 I also examined 169 terrorist organizations to determine the rate of decline for groups that had experienced leadership targeting compared to those that had not, and found that decapitation does not increase the likelihood of organizational collapse. Somewhat counterintuitively, organizations that have not experienced decapitation are more likely to cease activity than those that have. Whereas 53 percent of decapitated terrorist groups fell apart, 70 percent of groups that did not experience decapitation are no longer active. The rate of decline is almost 20 percent lower for decapitated organizations.

The data from this earlier study support the predictions that emerge from the theory of organizational resilience. The rate of organizational decline is lower for larger, older, religious, and separatist organizations. The data indicate that larger, older, and religious organizations are highly resilient to leadership targeting. These group-level variables provide a way to evaluate the theoretical variables examined in this article. A group's age and size can act as proxies for bureaucracy, while a group's type can act as a proxy for communal support. Data from previous empirical results thus support the claim that the most resilient groups should be the most likely to be bureaucratized and have local support. So, how do these data apply to the case of al-Qaida?

Since 2001 al-Qaida has undergone a sustained campaign of leadership attacks. (When referring to al-Qaida in this article, I mean the larger umbrella organization that encompasses al-Qaida's core and affiliated organizations. At times, I look at specific affiliated organizations and indicate when this is done.) Experts disagree over the degree to which these leadership attacks have damaged the organization and even how to evaluate al-Qaida as an organization. Al-Qaida is a complex organization, composed of a core based largely in Pakistan, a periphery, and affiliated groups in Yemen, Somalia, the Islamic Maghreb, Egypt, Iraq, and Saudi Arabia. Although different organizations, al-Qaida core, al-Qaida in Iraq (AQI), al-Qaida in the Arabian Peninsula (AQAP), and al-Qaida in the Islamic Maghreb (AQIM) have been subjects of U.S. counterterrorism policy. Moreover, the ideology to which each group adheres is largely consistent across the organization. Each group has goals specific to its region, but the overall message of inspiring potential recruits remains largely the same. Although decapitation may continue to produce short-term effects on the operational capacity of al-Qaida, targeting its leaders is unlikely to result in significant organizational degradation.

THE BUREAUCRATIC STRUCTURE OF AL-QAIDA

Bruce Hoffman describes al-Qaida as exercising both top-down and bottom-up planning and operational capabilities along four levels.66 First, al-Qaida's core leadership exerts “some coordination, if not command capability, in terms of commissioning attacks, directing surveillance and collating reconnaissance, planning operations, and approving their execution.”67 Members of the second level, al-Qaida affiliates and associates, belong to insurgent or terrorist groups and have received some form of assistance, either material or spiritual, from al-Qaida. This level includes terrorist and insurgent groups in Bosnia, Chechnya, Indonesia, Kashmir, the Philippines, and Uzbekistan. Occupying the third level are al-Qaida locals who adhere to al-Qaida's ideology, have some experience with terrorism, and have some previous connection with al-Qaida. Finally, the al-Qaida network comprises homegrown Islamic radicals and local converts to Islam who have no direct contact with al-Qaida but are prepared to carry out attacks in support of its agenda.68 While al-Qaida the organization, which is headed by Ayman al-Zawahiri, has further decentralized since Hoffman offered this description, it still has a functional leadership, identifiable affiliates or franchises, local militants, and homegrown radicals.69

Despite its increasingly decentralized structure, al-Qaida retains elements of a well-organized group with a central command.70 In testimony to the U.S. House Armed Services Committee, Hoffman observed that “[a]l-Qaida remains a hierarchical organization: capable of ordering, planning and implementing bold terrorist strikes.”71 Most al-Qaida affiliates, such as AQAP, AQI, and AQIM, have sworn bayat (loyalty) to al-Qaida's leadership.72 Hoffman and Fernando Reinares argue that al-Qaida's core has “shown itself capable of adapting and adjusting to even the most consequential countermeasures directed against it, having, despite all the odds, survived for nearly a quarter of a century.”73

Highly bureaucratized terrorist organizations can face a trade-off between maintaining security and exercising organizational control.74 Yet, Jacob Shapiro uses documents from al-Qaida in Iraq's successor organization, the Islamic State of Iraq, to show that the organization has exhibited a “non-trivial” level of bureaucracy despite risks to its security.75 An examination of primary documents captured during U.S. counterterrorism efforts against al-Qaida and its affiliates since the invasion of Iraq in 2003 reveals a high level of bureaucratic organization. These include documents from the Department of Defense's Harmony database that provide a sense of the inner workings of these organizations.76 The “Harmony documents” reveal “how explicit al-Qaida has been in its internal discussions covering a range of organizational issues, particularly regarding the internal structure and functioning of the movement as well as with tensions that emerged within the leadership.” James Forest, Jarret Brachman, and Joseph Felter argue that the Harmony collection offers insight into how al-Qaida developed “Western-styled bureaucratic structures.”77 The documents also identify recruitment criteria, training programs for new recruits, and tactics.

Al-Qaida's bylaws clearly explain the group's goals, principles, voting laws, processes for airing grievances, the importance of reports, details on organizational structure, members’ duties, leadership responsibilities, financial policies, budgetary requirements, and policies for different committees (military, political, and security).78 Employment contracts, which are signed under oath, lay out membership duties, holidays, salaries, travel details, rewards, and punishment.79 Al-Qaida has also kept membership rosters of martyred individuals.80

Documents retrieved by coalition forces in Sinjar during the Iraq War also provide valuable information about AQI. The 109 documents analyzed in a report by West Point's Combating Terrorism Center include signed contracts; policy memos; press releases; and managerial reports on personnel, finances, and equipment.81 Shapiro's chapter in this report focuses on the managerial challenges facing terrorist organizations. He observes that leaders have to delegate duties, a process that can result in preference divergence between principals and agents and requires monitoring of the latter. Shapiro finds that “[l]eaders typically exercise control over their agents through a standard set of bureaucratic tools including policy memoranda, reporting requirements, and tracking spreadsheets.”82 (This process by which leaders must monitor their agents is consistent with this article's understanding of bureaucracy.) Peter Bergen also finds that, like its parent organization, AQI is highly bureaucratized. Noting, for example, that AQI asked its non-Iraqi recruits to fill out applications asking for demographic information. AQI also kept detailed information on battle plans, pay sheets, minutes of meetings, prisoners, rosters, and vehicle records.83 Documents captured from AQI show an interest in organizations similar to AQAM documents that recorded intelligence and security information, operational activity, training, personnel, recruiting techniques, strategy, and political goals.

Al-Qaida core and many of its affiliates have thus adopted features of traditional bureaucracies. Its hierarchy, despite repeated leadership attacks, remains surprisingly relevant. And recently, al-Qaida has benefited from political upheaval in places such as Libya and Syria, taking advantage of this upheaval to reaffirm its relevance. Zawahiri, for example, has made public statements about the legitimacy of particular affiliated organizations and their relationship to al-Qaida core. Al-Qaida continues to expand into new areas through affiliated organizations being created in weak states such as Somalia, Mali, and Kenya. It has also developed ties with local jihadist groups. Overall, al-Qaida core's hierarchy, though weakened, has adapted and withstood leadership attacks. A key reason for this resilience is continued public support for the organization and its objectives.

AL-QAIDA AND COMMUNAL SUPPORT

The resonance of al-Qaida's beliefs within local communities has increased the organization's ability to withstand leadership targeting. Al-Qaida's philosophy transcends not only the charismatic bin Laden, but also his specific interpretation of Islam. As Rohan Gunaratna observes, initially most Islamic struggles against non-Muslim governments were primarily engaged in territorial campaigns. These guerrilla and terrorist groups did not subscribe to a “universalistic brand of Islam.”84 Bin Laden was an activist and an ideologue; he developed and expanded the appeal of al-Qaida's beliefs, including an anti-Western and anti-Israel message, to attract a broad base of support.85 Pape argues that much of al-Qaida's appeal, however, is the result of the Western occupation of Muslim lands.86 Moreover, the movement is multiethnic, further broadening its appeal and contributing to the global and resilient nature of al-Qaida's beliefs, support, and infrastructure.

Al-Qaida's propaganda operations have helped to extend its belief system to many parts of the world. The use of the internet has improved communication between al-Qaida core and its affiliates. As Marc Sageman writes, “[This development] is potentially dangerous, especially in the context of [the] regrouping of [the] al-Qaida leadership.”87 The appeal of al-Qaida's beliefs, the growth of decentralized networks, and the regrouping of al-Qaida's leadership indicate the futility of capturing or killing bin Laden and other leaders within the organization. Opinion polls offer a glimpse into the role of public support for al-Qaida and recognition of the kind of social services that it has provided to local communities.

PUBLIC OPINION POLLS

Public opinion surveys have generally found that although a significant number of people support al-Qaida and the goals of other militant groups, they object to their tactics.88 The data from these surveys show that support for al-Qaida declined from 2010 to 2013 as the public continued to express fear of Islamic militancy. A study by World Public Opinion in 2009 found that people in majority-Muslim countries supported al-Qaida's goals. According to the report, “Views of al-Qaida are complex. Majorities agree with nearly all of al-Qaida's goals to change U.S. behavior in the Muslim world, to promote Islamist governance, and to preserve and affirm Islamic identity.”89 Sixty-six percent of respondents in eight countries stated that U.S. naval forces in the Persian Gulf were a bad idea. A majority of respondents in Egypt, the Palestinian territories, and Jordan approved of attacks on U.S. troops based in Muslim countries. Another survey carried out by World Public Opinion in 2009 in Azerbaijan, Indonesia, Jordan, Nigeria, Pakistan, the Palestinian territories, and Turkey found similar results.90 Negative views toward al-Qaida stem largely from public discomfort over attacking civilians. The surveys indicate that the majority of respondents renounce the use of attacks on civilians to achieve political objectives.

Recent surveys carried out by the PEW Center's Global Attitudes Project found that across eleven different Muslim populations, 67 percent of respondents expressed concern about Islamic extremism. In surveys conducted in Indonesia, Jordan, Pakistan, Tunisia, and Turkey, Muslim respondents felt that extremism has increased. At the same time, extremist groups such as al-Qaida have seen a decline in popular support. A poll carried out by the PEW Center's Global Attitudes Project in March and April 2012 found that majorities in Egypt, Jordan, Lebanon, Pakistan, and Turkey expressed unfavorable views of al-Qaida.91 Although these trends might suggest that al-Qaida may become more susceptible to decapitation, this is unlikely for two reasons. First, it still benefits from large pockets of support; almost 35 percent of the population in the Palestinian territories, Indonesia, and Egypt still support it.92 Second, it is al-Qaida's affiliates, some of which are enjoying increasing levels of support, that are the predominate targets.

After the September 11, 2001, terrorist attacks, the leadership of al-Qaida and the Taliban moved across the border from Afghanistan to Pakistan.93 By 2009, al-Qaida controlled all seven agencies of the Federally Administered Tribal Areas, extending its reach into the North-West Frontier Province, almost as far as Peshawar.94 Given the importance of Pakistan to al-Qaida's current operational capacity, it is useful to examine Pakistani attitudes toward al-Qaida and jihad, in general. To evaluate support for militancy in Pakistan, Christine Fair, Neil Malhotra, and Jacob Shapiro surveyed 6,000 Pakistanis in April 2009. Their study, which they designed to analyze “beliefs about Islam, Sharia, the legitimacy and efficacy of jihad, and attitudes towards specific militant organizations,” found significant support for jihad, especially when carried out by nonstate actors.95 Citing “al-Qaida's vigorous marketing efforts to depict its activities as seeking justice for the world's Muslims,” 47 percent of their interviewees believed that al-Qaida was fighting for justice. Although this figure is smaller than the percentage of those who believed that other groups were fighting for justice, according to Fair, Malhotra, and Shapiro, it is still a substantial minority. Moreover, 37 percent of respondents believed that al-Qaida stood for democracy, and 47 percent felt that al-Qaida was protecting Muslims.96 Among its conclusions, the survey found that “jihad has a considerable legitimacy among Pakistanis.”97

In an earlier survey of urban Pakistanis, Shapiro and Fair looked at support for militant organizations.98 They found that “urban Pakistanis support small militant organizations when two conditions hold: (1) those organizations are using violence in support of political goals the individual cares about; and (2) violence makes sense as a way to achieve those goals, given the respondent's understanding of the strategic environment.”99 Taken together, this survey and the study referenced in the paragraph above suggest some Pakistani support for militancy.

Polls conducted by the Arab Barometer in Yemen, a country in which al-Qaida has succeeded in holding significant amounts of territory, indicate considerable support for terrorist attacks carried out against American targets. For example, when asked if U.S. involvement in the region justifies attacks against Americans anywhere in the world, 73.4 percent of respondents answered yes.100

SOCIAL SERVICES

Some organizations, such as Hamas and Hezbollah, have institutionalized their provision of social services. In contrast, al-Qaida has provided social services only in areas where the government's ability to reach local residents is limited.

Providing social services increases not only a terrorist organization's base of support, but also its ability to raise funds—facts that al-Qaida has learned from the success of social welfare programs implemented by terrorist groups such as Lashkar-e-Taiba in Pakistan, Hamas, and Hezbollah.101 To support this finding, Juan Zarate and David Gordon point to bin Laden's statement issued after the 2010 floods in Pakistan in which bin Laden “focused heavily on the need to ensure relief for the Pakistani people and called for the provision of aid and the creation of ‘a capable relief task force.’”102

Since 2010 al-Qaida has become more communally active in Somalia and Yemen, both weak states with largely tribal societies in which the government has been unable to provide adequate services. Al-Qaida has begun to fill this gap by building schools and providing a variety of social services.103 Seth Jones observes that, in Yemen, al-Qaida “has exploited a government leadership crisis and multiple insurgencies to cement control in several provinces along the Gulf of Aden.”104 He continues, “Al-Qaida's affiliates in Somalia and Iraq also appear to be maintaining a foothold where there are weak governments, with al-Shabab in Kismayo and southern parts of Somalia, and al-Qaida in Iraq in Baghdad, Diylal and Salah and Din provinces, among others.”105 This combination of territorial control and provision of services is likely to increase popular support for al-Qaida, making the organization harder to weaken, particularly through the targeting campaign currently being employed in Yemen.

The theory of organizational resilience presented in this article posits that leadership targeting is unlikely to diminish al-Qaida's long-term operational capacity to engage in terrorist activity. Al-Qaida's behavior fits the pattern of a group against which decapitation will be ineffective. Formed in 1988, al-Qaida has been in existence for more than twenty-five years, a point at which terrorist groups become very stable. As a religious organization, its goals include establishing a pan-Islamic caliphate, overthrowing non-Islamic regimes, and expelling infidels from Muslim countries.106 Considerable disagreement exists over the size of the organization. For example, looking at the number of al-Qaida fighters, Bergen argues that in 2009 the core comprised 100 to 150 members in Afghanistan; the heart of the network (which is now in Pakistan) contained a few hundred “free agent” foreign fighters; and the final layer was composed of several thousand militant Pashtun tribal members.107 Excluding the Pashtun tribal members, al-Qaida still has at least 400 active members. Director of Central Intelligence Leon Panetta estimated that al-Qaida in Afghanistan consisted of 50 to 100 militants, but that “the main location of al-Qaeda is in the tribal areas of Pakistan.”108 The rate of collapse for decapitated groups with between 100 and 500 members is nearly 35 percent lower than for groups with 25 to 100 members. Even using a conservative estimate, destabilizing al-Qaida will be difficult. If one takes its affiliates into consideration, the organization is likely to be even more resilient.

Decapitation has not led to al-Qaida's demise, nor has it resulted in long-term organizational degradation. The remainder of this section evaluates changes in the frequency and lethality of its attacks. As mentioned earlier, one of the key challenges when discussing the operational capacity of al-Qaida is deciding whether to evaluate the organization as a whole or to disaggregate the analysis by evaluating al-Qaida core and its affiliated organizations separately. Here I assess al-Qaida as a whole unless otherwise specified. U.S. counterterrorism policy has increased its efforts in Yemen, Somalia, and Pakistan, indicating that the affiliated organizations are seen as posing serious national security threats. From 2001 to 2011, al-Qaida as a whole underwent 109 attacks on its leadership, weakening the operational capacity of its core.109 Some of its affiliated organizations, however, including AQAP, AQI, and AQIM continue to launch frequent, highly lethal attacks. Many scholars see AQAP as a significant and immediate threat, and the data here are consistent with that view. In Syria, Jabhat al-Nusra has become an effective force in fighting Bashar al-Assad's regime. The Islamic State of Iraq and Syria continues to operate and has, in fact, increased the frequency of its attacks against Shiite targets since the U.S. withdrawal.

Figure 2 plots instances of leadership decapitation against al-Qaida from 2001 to 2011. Figure 3 plots the number of attacks carried out by al-Qaida from 2001 to 2011.110 I use the Global Terrorism Database to identify the number and lethality of al-Qaida attacks. The data show that despite a sizable decline in 2006 and a smaller dip in 2009, the number of attacks carried out by al-Qaida rose steadily after the September 11 attacks with the beginning of the United States’ sustained targeting campaign. In 2010 the number of attacks against al-Qaida's leadership reached its peak, as did the number of attacks perpetrated by al-Qaida in 2011. Thus, despite having experienced the most intense period of targeting in 2010, the organization not only managed to recover, but was able to execute more attacks. Essentially, al-Qaida did not suffer a period of degradation.

Figure 2.

Instances of Decapitation against al-Qaida, 2001–11

Figure 2.

Instances of Decapitation against al-Qaida, 2001–11

Figure 3.

Al-Qaida Attacks, 2001–11

Figure 3.

Al-Qaida Attacks, 2001–11

Figure 4 and table 1 display the total number of attacks by all al-Qaida affiliates from 2001 to 2011. During this period, AQAP experienced a dramatic rise in attacks despite major U.S. targeting efforts carried out against al-Qaida operatives in Yemen. AQIM witnessed a decrease in activity every year following its peak in 2007. AQI, which carried out 60 attacks in 2005, saw a decline in activity in 2009, which in part could be a result of the U.S. surge in 2007. The number of AQI attacks, however, increased after the 2009 decline. Overall, the data indicate that al-Qaida affiliates proved remarkably resilient despite continued U.S. targeting operations.

Figure 4.

Al-Qaida Affiliates Number of Attacks per Year, 2001–11

Figure 4.

Al-Qaida Affiliates Number of Attacks per Year, 2001–11

Table 1.

Al-Qaida Affiliates—Number of Attacks, 2001–11

GroupNumber of Attacks
Al-Qaida 52 
Al-Qaida in Iraq 200 
Al-Qaida in the Arabian Peninsula 143 
Al-Qaida in the Islamic Maghreb 184 
GroupNumber of Attacks
Al-Qaida 52 
Al-Qaida in Iraq 200 
Al-Qaida in the Arabian Peninsula 143 
Al-Qaida in the Islamic Maghreb 184 

SOURCE: Data taken from the Global Terrorism Database.

Finally, figure 5 shows the lethality of attacks by al-Qaida and affiliates from 2001 to 2011. The highest number of deaths occurred in 2001, with the September 11 attacks.111 Al-Qaida core carried out only one small attack in 2011, but its affiliates launched numerous lethal attacks, despite ongoing targeting campaigns against both their leaderships and lower-level operatives. Al-Qaida affiliates were responsible for the deaths of nearly 700 individuals in 2011 alone.

Figure 5.

Lethality of al-Qaida Attacks, 2002–11

Figure 5.

Lethality of al-Qaida Attacks, 2002–11

The figures above do not indicate significant degradation of organizational capacity or a marked disruption in al-Qaida's activities. Still, the United States will likely continue its targeting operations, with a particular focus on leaders who possess operational roles. For example, al-Qaida's Atiyah Abd al-Rahman, who was killed by a drone strike in Pakistan in August 2011, communicated important information between the core in Pakistan and other al-Qaida affiliates. At the time of his death, it was argued that he would be very hard to replace. Nevertheless, he was replaced by Abu Yahya al-Libi, who was later killed by a drone strike in Pakistan in June 2012. Organizations may have difficulty regrouping after successful targeting efforts, yet ultimately their leaders will be replaced. There is a vast supply of new recruits who can be trained to fill their spots, and organizations with bureaucratic institutions should have an easier time with this succession process.

Despite its operational weakness, al-Qaida's core remains active. It continues to provide leadership directives to the larger movement. For example, in November 2013 and again in February 2014, Ayman al-Zawahiri stated that the Islamic State of Syria was formed to operate in Syria without permission from the organization's main command, that it should cease operations, and that Jabhat al-Nusra should remain an affiliated branch of al-Qaida.112 Michael Vickers, who has served as the Pentagon's undersecretary for defense intelligence since 2011, argues that even a severely weakened al-Qaida core would probably remain a propaganda arm.113 Propaganda has been critical to inspiring new recruits and is important in maintaining al-Qaida core's ties to its affiliates.114 And as Megan Smith and James Igoe Walsh argue, despite having undergone numerous drone strikes, al-Qaida has been able to continue generating propaganda for its cause.115

Leadership targeting has become a cornerstone of U.S. counterterrorism policy. Although targeting leaders can be effective in some cases, it is unlikely to result in the collapse of terrorist organizations generally being targeted today. Even if organizations are weakened after the killing or arrest of their leaders, they tend to survive, regroup, and continue carrying out attacks. The findings of this study have four implications for U.S counterterrorism policy.

First, decapitation can have counterproductive or adverse consequences, particularly if the leader plays a key inspirational or spiritual role.116 In the aftermath of the targeting of its leader, an organization may be motivated to retaliate. Terrorist organizations will often identify such targeting as the motive for their subsequent attacks. Revenge can be a powerful motivator: not only does killing a terrorist leader inspire the desire for retaliation on the part of an organization, but it can also increase sympathy and support for the organization from local and international communities.117 Civilian deaths can intensify this motive. Hamas, for example, has engaged in numerous acts of retaliation in response to the killing of some of its key leaders. After the assassination of Yahya Ayyash, Hamas's chief bomb maker, the group carried out four retaliatory bus bombings, which killed more than fifty people.118 The assassinations of Hamas leaders Sheikh Ahmed Yassin and Abdel Aziz al-Rantisi triggered massive local and international outrage. Yassin's death was condemned by the international community and unleashed a huge amount of sympathy throughout Palestinian society.119 Rantisi's death spurred less international condemnation than Yassin's, but it was a more serious loss for the organization. Rantisi was a skilled organizer with popular support. Clearly, bin Laden's death did not result in international condemnation or outrage, yet it is important to consider how sympathy and revenge can further motivate a terrorist organization.

Second, heavy-handed counterterrorism polices can generate organizational support. Policies that are seen as unreasonably severe can result in outrage toward the government employing them. Atran argues that coercive tactics do not dampen popular support for jihadist movements.120 The manner in which a state responds to terrorism can affect militant sentiments, the local population, and the international community.121 In response to the September 11 attacks, the United States launched ground invasions in Afghanistan and Iraq, both of which generated much sympathy for the militants and fierce condemnation of the U.S. decision to invade Iraq.

Third, drone strikes have had a significant impact on public opinion, not only in Pakistan and Yemen (the most frequent targets of these attacks), but also internationally.122 Although drone strikes have been in decline since 2012, they are still one of the primary ways to target terrorist leaders. These strikes can result in civilian casualties, which can generate sympathy for the groups being targeted.123 The New America Foundation estimates that, in 351 strikes, between 261 and 305 civilians were killed out of a total of 1,965 to 3,295 dead. The Bureau of Investigative Journalism estimates that, in 366 strikes, between 411 and 884 civilians were killed out of a total of 2,537 to 3,581.124 A study by Stanford and New York University argues that drone strikes have resulted in considerable civilian death, and as such are not supported by local civilians.125 As noted earlier, civilian deaths can increase local support for the targeted organization, fuel recruitment, and lessen support for counterterrorism policies.126 It should be noted, however, that it is hard to obtain reliable public opinion in Federally Administrated Tribal Areas. Moreover, some locals have hidden their opposition to drone strikes to avoid being seen as pro-Taliban. As a result, the level of public opposition to drones could be much higher than reported. Although it is unlikely that the use of such strikes will subside, criticism of their legality, efficacy, and consequences will remain prominent within public discourse.127

Fourth, future leaders may be more radical in their beliefs or more violent in their tactics. Leadership succession among Chechen militants and the Provisional Irish Republican Army demonstrates that more radical or violent leaders can emerge in the power vacuum left by a leader's death or arrest, potentially increasing both the frequency and lethality of future attacks.

In the case of al-Qaida, there is reason to believe that continued targeting also has potential for counterproductive consequences. Decapitation efforts against al-Qaida could instigate retaliatory attacks, fuel recruitment, or generate more sympathy for the movement, ultimately strengthening it. According to Bergen, although al-Qaida does not pose a significant threat to U.S. national security, the group is likely to withstand the capture or death of key leaders.128 He has argued that, in the short term, bin Laden's death would lead to anti-American attacks around the globe and, in the medium term, would be a major blow to the organization.129 Consistent with the findings of this study, Bergen has concluded that in the long term, bin Laden's death would bolster the power of his ideas, ultimately strengthening the organization. The resilience of these ideas is grounded in the belief of al-Qaida's members that they are carrying out a holy mission.130

The targeting of terrorist leaders affiliated with al-Qaida has been the cornerstone of U.S. counterterrorism policy since 2001. This article has developed a theoretical explanation for when targeting is effective. Terrorist organizations that possess characteristics such as bureaucratic forms of organization or substantial levels of communal support are more likely to survive attacks on their leadership than those that do not.

Using size and age to serve as proxies for bureaucracy and organizational type as a proxy for communal support, I found that older, larger, and religious groups are more likely to resist destabilization in the face of leadership attacks than are younger, smaller, ideological groups. Larger and older organizations tend to have more bureaucratic traits than smaller or younger groups, and religious and separatist groups have higher levels of local support than ideologically oriented organizations.

In the immediate aftermath of decapitation, a terrorist organization is often temporarily weakened, affecting its operational capacity. During this period, it will attempt to reorganize its leadership. From a counterterrorism perspective, the key objective is to prevent the organization from regrouping and reengaging in hostile activity. My examination of al-Qaida leads me to conclude that targeting al-Qaida is not likely to result in organizational decline or long-term degradation. Its bureaucratic organization and communal support have allowed it to withstand frequent attacks on its leadership. Although it has been weakened since the 2001 invasion of Afghanistan and subsequent efforts to kill or capture key leaders, it has adapted to a changing landscape. Moreover, the weakening of al-Qaida's core in Pakistan has not meant the decline of its affiliates and may embolden some of these groups to increase their level of militancy to achieve greater legitimacy within the extremist community.

Regardless of the effectiveness and potential for adverse consequences of its decapitation strategy, the United States is likely to continue targeting al-Qaida leaders because U.S. policymakers view the killing of high-level targets, such as bin Laden, al-Libi, al-Rahman, Kashmiri, and Mauritania, as successes in themselves. Ultimately, however, leadership targeting alone is not enough to effectively fight a strong and emboldened terrorist organization.

For helpful comments and suggestions, the author is grateful to Max Abrahms, Mia Bloom, Anne Holthoefer, John Horgan, Charles Lipson, Chris McIntosh, John Mearsheimer, Michelle Murray, Robert Pape, Dan Reiter, Sebastian Rosato, Lawrence Rubin, Keven Ruby, seminar participants at the Program on International Politics, Economics, and Security and the Program on International Security Policy at the University of Chicago and the Security Policy Workshop Series at the Elliott School of International Affairs at George Washington University, conference participants at the annual meetings of the International Studies Association and the American Political Science Association, and the anonymous reviewers.

1. 

According to the data on drone strikes collected by Peter Bergen and Katherine Teidemann at the New America Foundation, the United States carried out 9 strikes in 2004, 118 in 2010, 72 in 2011, 48 in 2012, and 9 from January 1 through March 10, 2013. See http://counterterrorism.new america.net/drones. For data on drone strikes from the Bureau of Investigative Journalism, see http://www.thebureauinvestigates.com/category/projects/drones/.

2. 

Declan Walsh and Eric Schmitt, “Drone Strike Killed No. 2 in Al Qaeda, U.S. Officials Say,” New York Times, June 5, 2012. In the aftermath of al-Libi's death, Peter Bergen argued that Ayman al-Zawahiri was likely the only remaining influential leader in al-Qaida. See Bergen, “And Now, Only One Senior al Qaeda Leader Left,” CNN Opinion, June 6, 2012, http://articles.cnn.com/2012-06-05/opinion/opinion_bergen-al-qaeda-whos-left_1_abu-yahya-aqap-drone-strikes?_s=PM:OPINION.

3. 

Mark Mazzetti, Eric Schmitt, and Robert F. Worth, “Two-Year Manhunt Led to Killing of Awlaki in Yemen,” New York Times, September 30, 2011.

4. 

Mark Mazzetti, “C.I.A. Drone Is Said to Kill Al Qaeda's No. 2,” New York Times, August 27, 2011.

5. 

Not only have drone strikes been used to kill militant leaders, but they have also been employed against lower-level operatives and antigovernment insurgent leaders in countries such as Pakistan and Yemen, often with the acquiescence of those countries’ governments. Furthermore, although drone strikes serve as an important tool for targeting leaders, they are not synonymous with leadership decapitation. This article focuses on the efficacy of targeting terrorist leaders.

6. 

See Max Weber, The Theory of Economic and Social Organization (New York: Free Press, 1964), p. 358.

7. 

Max Weber, From Max Weber: Essays in Sociology, trans. H.H. Gerth and C. Wright Mills (New York: Oxford University Press, 1946).

8. 

Bryan C. Price, “Targeting Top Terrorists: How Leadership Decapitation Contributes to Counterterrorism,” International Security, Vol. 36, No. 4 (Spring 2012), p. 14.

9. 

Michael Freeman, “The Headless Horseman: A Theoretical and Strategic Assessment of Leadership Targeting,” Terrorism and Political Violence, forthcoming.

10. 

Cynthia McClintock, Revolutionary Movements in Latin America: El Salvador's FMLN and Peru's Shining Path (Washington, D.C.: United States Institute of Peace Press, 1998), p. 92.

11. 

Audrey Kurth Cronin, How Terrorism Ends: Understanding the Decline and Demise of Terrorist Campaigns (Princeton, N.J.: Princeton University Press, 2009), p. 17.

12. 

See Daniel Byman, “Do Targeted Killings Work?” Foreign Affairs, Vol. 85, No. 2 (March/April 2006), pp. 95–111; Kathleen M. Carley, Ju-Sung Lee, and David Krackhardt, “Destabilizing Networks,” Connections, Vol. 24, No. 3 (2002), pp. 79–92; and James D. Thompson, Organizations in Action: Social Science Bases of Administrative Theory (New Brunswick, N.J.: Transaction, 2007).

13. 

See Kathleen M. Carley, “A Theory of Group Stability,” American Sociological Review, Vol. 56, No. 3 (June 1991), pp. 331–354; and Carley, Lee, and Krackhardt, “Destabilizing Networks.”

14. 

Patrick B. Johnston, “Does Decapitation Work? Assessing the Effectiveness of Leadership Targeting in Counterinsurgency Campaigns,” International Security, Vol. 36, No. 4 (Spring 2012), p. 50.

15. 

Johnston, “Does Decapitation Work?” p. 75. These findings run counter to mine and to Price's. Johnston’, however, uses ten years as a marker when analyzing the role organizational age plays in decapitation effectiveness. Had he divided groups over eleven years of age into different categories, these results might have changed. Both Price and I found that once a group crosses the twenty-year threshold, decapitation becomes much less effective.

16. 

Organizational degradation can be measured by looking at both the frequency and lethality of a group's attacks. In the 2011 study, I measured organizational degradation following decapitation strikes against the Revolutionary Armed Forces of Colombia, the Basque separatist organization ETA, and Hamas. See Jenna Jordan, “When Heads Roll: Assessing the Effectiveness of Leadership Decapitation,” Security Studies, Vol. 18, No. 4 (October 2009), pp. 719–755.

17. 

Michel Crozier, The Bureaucratic Phenomenon (Chicago: University of Chicago Press, 1963).

18. 

Crozier also discusses how a bureaucratic system of routine and rules can contribute to a “vicious cycle” in which individuals try to avoid face-to-face relationships. See ibid., p. 54.

19. 

Talcott Parsons, introduction, in Max Weber, The Theory of Social and Economic Organization, trans. A.M. Henderson and Parsons (New York: Free Press, 1947), p. 58.

20. 

Weber, From Max Weber.

21. 

Peter H. Grinyer and Masoud Yasai-Ardekani, “Strategy, Structure, Size, and Bureaucracy,” Academy of Management Journal, Vol. 24, No. 3 (September 1981), p. 475. See also Jodi Vittori, “All Struggles Must End: The Longevity of Terrorist Groups,” Contemporary Security Policy, Vol. 30, No. 3 (December 2009), p. 445.

22. 

Vittori, “All Struggles Must End,” p. 445.

23. 

David Veness, “Terrorism and Counterterrorism: An International Perspective,” Studies in Conflict and Terrorism, Vol. 24, No. 5 (September/October 2001), p. 410.

24. 

Vittori, “All Struggles Must End.” This is particularly apparent in the case of Hamas, an organization with separate wings that are assigned different tasks such as bomb making, logistical planning, or spiritual advising. Its resilience can be traced in part to its diversified functions and resource bases.

25. 

I make a distinction between efficiency and stability. “Efficiency” refers to how capably an organization functions, whereas “stability” refers to how well a group can respond to counterterrorism efforts and other challenges to its existence.

26. 

Martha S. Feldman and Brian T. Pentland, “Reconceptualizing Routines as a Source of Flexibility and Change,” Administrative Science Quarterly, Vol. 48, No. 1 (March 2003), p. 94. See also James G. March and Herbert A. Simon, Organizations (Cambridge, Mass.: Blackwell, 1993); and Thompson, Organizations in Action.

27. 

Barbara Levitt and James G. March, “Organizational Learning,” American Review of Sociology, Vol. 14 (1988), p. 320.

28. 

Mark A. Hager, Joseph Galaskiewicz, and Jeff A. Larson, “Structural Embededdness and the Liability of Newness among Nonprofit Organizations,” Public Management Review, Vol. 6, No. 2 (June 2004), p. 162.

29. 

Jacob N. Shapiro argues that terrorist organizations often face a choice between maintaining secrecy or efficiency. See Shapiro, The Terrorist's Dilemma: Managing Violent Covert Organizations (Princeton, N.J.: Princeton University Press, 2013).

30. 

See Josef Bruderl and Rudolf Schussler, “Organizational Mortality: The Liabilities of Newness and Adolescence,” Administrative Science Quarterly, Vol. 35, No. 3 (September 1990), pp. 530–547; John Freeman, Glenn R. Carroll, and Michael T. Hannan, “The Liability of Newness: Age Dependence in Organizational Death Rates,” American Sociological Review, Vol. 48, No. 5 (October 1983), pp. 692–710; Mark A. Hager et al., “Tales from the Grave: Organizations’ Accounts of Their Own Demise,” American Behavioral Scientist, Vol. 39 (August 1996), pp. 975–994; Hager, Galaskiewicz, and Larson, “Structural Embededdness and the Liability of Newness among Nonprofit Organizations”; Michael T. Hannan and John Freeman, “The Population Ecology of Organizations,” American Journal of Sociology, Vol. 82, No. 5 (March 1977), pp. 929–964; Robert O. Keohane, “The Demand for International Regimes,” International Organization, Vol. 36, No. 2 (Spring 1982), pp. 325–355; Jitendra V. Singh, David J. Tucker, and Robert J. House, “Organizational Legitimacy and the Liability of Newness,” Administrative Science Quarterly, Vol. 31, No. 2 (June 1986), pp. 171–193; and James Ranger-Moore, “Bigger May Be Better, but Is Older Wiser? Organizational Age and Size in the New York Life Insurance Industry,” American Sociological Review, Vol. 62, No. 6 (December 1992), pp. 903–920.

31. 

Arthur Stinchcombe, “Organizations and Social Structure,” in J.G. March, ed., Handbook of Organizations (Chicago: Rand McNally, 1965), pp. 142–193. Numerous studies support the empirical accuracy of the liability of newness thesis. See Ranger-Moore, “Bigger May Be Better, but Is Older Wiser?”; Freeman, Carroll, and Hannan, “The Liability of Newness”; Hager, Galaskiewicz, and Larson, “Structural Embededdness and the Liability of Newness among Nonprofit Organizations”; and Singh, Tucker, and House, “Organizational Legitimacy and the Liability of Newness.”

32. 

The liability of newness thesis is widely accepted by organizational theorists; studies have scrutinized its empirical roots, tested its accuracy, and generally confirmed that younger organizations have a higher failure rate than older organizations. See Ranger-Moore, “Bigger May Be Better, but Is Older Wiser?”; Bruderl and Schussler, “Organizational Mortality”; and Freeman, Carroll, and Hannan, “The Liability of Newness.”

33. 

See Jack A. Nickerson and Todd R. Zenger, “Comment: Dynamically Engineering Bureaucracy,” Journal of Law, Economics, and Organization, Vol. 15, No. 1 (April 1999), pp. 47–55; and James N. Baron, M. Diane Burton, and Michael T. Hannan, “Engineering Bureaucracy: The Genesis of Formal Policies, Positions, and Structures in High-Technology Firms,” Journal of Law, Economics, and Organization, Vol. 15, No. 1 (March 1999), pp. 1–41. Importantly, terrorist organizations do not necessarily increase in size as they age. Independent of the relationship between size and age, however, organizations that age or grow larger are more likely to develop some of the characteristics of bureaucracies that prove useful when carrying out an effective terrorist campaign.

34. 

See Shapiro, The Terrorist's Dilemma.

35. 

Although Weber argues that a hierarchical system of authority is a critical feature of a bureaucracy, Roger Mansfield notes, “At no point did he [Weber] suggest, however, that centralization of decision making in such a hierarchy was a characteristic of bureaucracy nor did he even make explicit the relationship between bureaucracy and centralization.” Mansfield points to “the absence of any positive relationship between centralization and bureaucratization. In general there is some evidence of negative association between these variables.” See Mansfield, “Bureaucracy and Centralization: An Examination of Organizational Structure,” Administrative Science Quarterly, Vol. 18, No. 4 (December 1973), pp. 477–488.

36. 

In discussing this quasi-bureaucratic organizational structure, Michael Kenney claims that the decentralized nature of networks “does not preclude the existence of vertical decisionmaking hierarchies within nodes that carry out the network's most dangerous activities.” See Kenney, From Pablo to Osama: Trafficking and Terrorist Networks, Government Bureaucracies, and Competitive Adaptation (University Park: Pennsylvania State University Press, 2007).

37. 

Weber, From Max Weber, p. 54.

38. 

See Roger D. Petersen, Resistance and Rebellion (Cambridge: Cambridge University Press, 2001); and Scott Atran, “Mishandling Suicide Terrorism,” Washington Quarterly, Vol. 27, No. 3 (Summer 2004), pp. 67–90. Although terrorist movements differ from insurgencies, many of the cases that I evaluate could be classified as involving both terrorist organizations and insurgent organizations. Insurgent organizations may adopt a strategy of terrorism, guerrilla warfare, or more conventional warfighting. This explains the partial overlap between studies of insurgencies and terrorist campaigns. Matthew Kocher suggests that the difference between terrorist groups and insurgent organizations is grounded in strategic choice. Terrorist organizations employ a strategy of punishment, whereas insurgencies use a strategy of denial. This definition, too, allows for potential overlap. For example, the Kurdistan Workers’ Party uses denial in rural areas and punishment in urban areas.

39. 

Paul Collier and Anke Hoeffler, “Greed and Grievance in Civil War,” Oxford Economic Papers, Vol. 56, No. 4 (October 2004), pp. 563–595.

40. 

See Ted Robert Gurr, Why Men Rebel (Princeton, N.J.: Princeton University Press, 1970). For a discussion of different views regarding popular support and counterinsurgency strategy, see Eli Berman, Jacob N. Shapiro, and Joseph H. Felter, “Can Hearts and Minds Be Bought? The Economics of Counterinsuregncy in Iraq,” Journal of Political Economy, Vol. 119, No. 4 (August 2011), pp. 766–819. Berman and his coauthors demonstrate an important relationship between the provision of local public goods and a reduction in insurgent violence.

41. 

Although Petersen does not discuss terrorist organizations specifically, he looks at rebellion as a general concept. See Petersen, Resistance and Rebellion.

42. 

Robert A. Pape, Dying to Win: The Strategic Logic of Suicide Terrorism (New York: Random House, 2005), p. 81.

43. 

Atran, “Mishandling Suicide Terrorism,” p. 82.

44. 

Pape, Dying to Win.

45. 

Mia Bloom, Dying to Kill: The Allure of Suicide Terror (New York: Columbia University Press, 2005).

46. 

See Risa A. Brooks, “Societies and Terrorist Violence: How Social Support Affects Militant Campaigns,” Marquette University, 2011, p. 27.

47. 

Ibid., pp. 27–28.

48. 

Cronin, How Terrorism Ends, p. 104.

49. 

Cronin points to the Weather Underground, the Red Army Faction, and 17 November as examples of groups whose ideologies became irrelevant. She also includes in this category groups that were supported by the Soviet Union and thus became historically irrelevant after its collapse. See ibid., pp. 105–106.

50. 

For a discussion of how insurgent groups’ survival depends on local supporters providing the means to acquire and hide resources, see Jeremy M. Weinstein, Inside Rebellion: The Politics of Insurgent Rebellion (Cambridge: Cambridge University Press, 2007); and Jeremy M. Weinstein, “Resources and the Information Problem in Rebel Recruitment,” Journal of Conflict Resolution, Vol. 49, No. 4 (August 2005), pp. 598–624.

51. 

See John D. McCarthy and Mayer N. Zald, “Social Movement Organizations,” in Jeff Goodwin and James M. Jasper, eds., The Social Movements Reader: Cases and Concepts (Chichester, U.K.: Wiley-Blackwell, 2009), pp. 193–210. Neil J. Smelser also questions the usefulness of the deprivation model in accounting for the occurrence of terrorist movements. See Smelser, The Faces of Terrorism: Social and Psychological Dimensions (Princeton, N.J.: Princeton University Press, 2007).

52. 

Jeff Goodwin, No Other Way Out: States and Revolutionary Movements, 1945–1991 (Cambridge: Cambridge University Press, 2001), p. 57.

53. 

Mayer N. Zald and Roberta Ash, “Social Movement Organizations: Growth, Decay, and Change,” Social Forces, Vol. 44, No. 3 (March 1966), pp. 327–341.

54. 

Zald and Ash argue that older organizations are more likely to have stable structures, increasing their ability to reach isolated adherents and thus potential constituents. Larger groups are also better able to reach isolated adherents and should thus have larger bases of support, enabling access to more resources. See ibid.

55. 

Doug McAdam, Political Process and the Development of Black Insurgency, 1930–1970 (Chicago: University of Chicago Press, 1999), p. 46.

56. 

Ami Pedahzur and Arie Perlinger, “The Changing Nature of Suicide Attacks: A Social Network Perspective,” Social Forces, Vol. 84, No. 4 (June 2006), pp. 1987–2008; and Ziad Abu-Amr, “Hamas: A Historical and Political Background,” Journal of Palestine Studies, Vol. 22, No. 4 (Summer 1993), p. 15.

57. 

Shaul Mishal, “The Pragmatic Dimension of the Palestinian Hamas: A Network Perspective,” Armed Forces and Society, Vol. 29, No. 4 (Summer 2003), pp. 569–589; and Sara Roy, “Hamas and the Transformation(s) of Political Islam in Palestine,” Current History, January 2003, pp. 13–20.

58. 

Eli Berman and David D. Laitin, “Religion, Terrorism, and Public Goods: Testing the Club Model,” Journal of Public Economics, Vol. 92, Nos. 10–11 (October 2008), pp. 1942–1967.

59. 

Bloom, Dying to Kill.

60. 

Mia Bloom, “Dying to Kill: Motivations for Suicide Terrorism,” in Ami Pedahzur, ed., Root Causes of Suicide Terrorism: The Globalization of Martyrdom (New York: Routledge, 2006), p. 49.

61. 

The category “ideological organizations” includes both left-wing and right-wing groups. For further discussion of how I classify organizations, see Jordan, “When Heads Roll.”

62. 

James Ron, “Ideology in Context: Explaining Sendero Luminoso's Tactical Escalation,” Journal of Peace Research, Vol. 38, No. 5 (September 2001), pp. 569–572.

63. 

There are cases in which the opposite is true. I argue, however, that this trend should be predominant.

64. 

This quadrant should also contain the fewest outliers.

65. 

Jordan, “When Heads Roll.”

66. 

See Bruce Hoffman, “The Myth of Grass-Roots Terrorism: Why Osama Bin Laden Still Matters,” Foreign Affairs, Vol. 87, No. 3 (May/June 2008), pp. 133–138.

67. 

Bruce Hoffman, “Combating Al Qaeda and the Militant Islamic Threat,” written testimony submitted to the U.S. House Armed Services Subcommittee on Terrorism, Unconventional Threats, and Capabilities (Santa Monica, Calif.: RAND, February 16, 2006), p. 3.

68. 

See ibid. For a debate about the intensity of the threat from homegrown terrorism, see Hoffman, “The Myth of Grass-Roots Terrorism”; and Bruce Hoffman and Marc Sageman, “Does Osama Still Call the Shots? Debating the Containment of Al Qaeda's Leadership,” Foreign Affairs, Vol. 87, No. 4 (July/August 2008), pp. 163–166.

69. 

See Canadian Security Intelligence Service, “The Future of Al-Qaeda: Results of a Foresight Project” (Ottawa: Canadian Security Intelligence Service, 2013). Thomas Joscelyn concurs with this assessment of al-Qaida. See Joscelyn, testimony to the U.S. House Committee on Foreign Affairs, Subcommittee on Terrorism, Nonproliferation, and Trade, 113th Cong., 1st sess., July 18, 2013 (Washington, D.C.: Congressional Record).

70. 

Hoffman, “Combating Al Qaeda and the Militant Islamic Threat,” p. 3.

71. 

Bruce Hoffman, written testimony submitted to the U.S. House Armed Services Committee, Subcommittee on Terrorism, Unconventional Threats and Capabilities, 110th Cong., 1st sess., February 14, 2007, http://www.fas.org/irp/congress/2007_hr/socom.pdf.

72. 

Joscelyn, testimony to the U.S. House Committee on Foreign Affairs, Subcommittee on Terrorism, Nonproliferation.

73. 

Bruce Hoffman and Fernando Reinares, “Al-Qaeda's Continued Core Strategy and Disquieting Leader-Led Trajectory,” ARI 37/2013 (Madrid: Elcano Royal Institute, September 10, 2013), p. 3.

74. 

Jacob N. Shapiro and David A. Siegel, “Moral Hazard, Discipline, and the Management of Terrorist Organizations,” World Politics, Vol. 64, No. 1 (January 2009), pp. 39–78; Jacob N. Shapiro, “Bureaucracy and Control in Terrorist Organizations,” Princeton University, 2008; and Shapiro, The Terrorist's Dilemma.

75. 

Shapiro, The Terrorist's Dilemma.

76. 

Harmony documents (originals and translations) are available through the Combating Terrorism Center website, http://www.ctc.usma.edu/programs-resources/harmony-program.

77. 

James J.F. Forest, Jarret Brachman, and Joseph H. Felter, “Harmony and Disharmony: Exploiting al-Qa'ida's Oganization Vulnerabilities” (West Point, N.Y. Combating Terrorism Center at West Point, 2006), p. 2. According to Shapiro, this level of bureaucratization not only lessens the effect of preference divergence, but can increase efficiency and signal legitimacy for local populations. See Shapiro and Siegel, “Moral Hazard, Discipline, and the Management of Terrorist Organizations”; and Shapiro, The Terrorist's Dilemma.

78. 

“Al-Qaida's Structure and Bylaws (English Translation),” Harmony #AFGP-2002-600048 (West Point, N.Y.: Combating Terrorism Center at West Point, n.d.).

79. 

“Al Qaida Constitutional Charter (Original Language),” Harmony #AFGP-2002-600045 (West Point, N.Y.: Combating Terrorism Center at West Point, n.d.).

80. 

“List of Names of Al-Qaida Members (Original Language),” Harmony #AFGP-2002-600046 (West Point, N.Y.: Combating Terrorism Center at West Point, n.d.).

81. 

Brian Fishman et al., “Bombers, Bank Accounts, and Bleedout: Al-Qa'ida's Road in and out of Iraq” (West Point, N.Y.: Combating Terrorism Center at West Point, 2008).

82. 

Jacob Shapiro, “Bureaucratic Terrorists: Al-Qa'ida in Iraq's Management and Finances,” in ibid., p. 75.

83. 

Peter Bergen, The Longest War: The Enduring Conflict between America and Al-Qaeda (New York: Free Press, 2011), p. 169.

84. 

Rohan Gunaratna, Inside Al Qaeda: Global Network of Terror (New York: Columbia University Press, 2002), pp. 71–72.

85. 

Ibid.

86. 

See Robert A. Pape and James K. Feldman, Cutting the Fuse: The Explosion of Global Suicide Terrorism and How to Stop It (Chicago: University of Chicago Press, 2010); and Pape, Dying to Win.

87. 

Marc Sageman, Leaderless Jihad: Terror Networks in the Twenty-first Century (Philadelphia: University of Pennsylvania Press, 2008), p. 130.

88. 

For a discussion of support for militant causes, see Bloom, Dying to Kill. Robert Pape and Kenneth Feldman analyze surveys by Shibley Tehami and find little support for al-Qaida's tactics and mixed support for its goals. Pape and Feldman claim that despite the lack of support for reestablishing an Islamic caliphate, there is support for al-Qaida's opposition to U.S. military policy. They find pockets of sympathy for al-Qaida in Egypt, Saudi Arabia, and Morocco, which the authors attribute to al-Qaida's strategic targeting of the United States. See Pape and Feldman, Cutting the Fuse, p. 180.

89. 

Steven Kull et al., “Public Opinion in the Islamic World on Terrorism, al Qaeda, and U.S. Policies,” WorldPublicOpinion.org, February 25, 2009, p. 3.

90. 

Steven Kull et al., “Public Opinion in the Islamic World on Terrorism, al Qaeda, and U.S. Policies.”

91. 

Pew Research Center, Global Attitudes Project, “On Anniversary of bin Laden's Death, Little Backing of al Qaeda,” April 30, 2012, http://www.pewglobal.org/2012/04/30/on-anniversary-of-bin-ladens-death-little-backing-of-al-qaeda/.

92. 

Seth G. Jones, “Think Again: Al Qaeda,” Foreign Policy, April 23, 2012, http://www.foreignpolicy.com/articles/2012/04/23/think_again_al_qaeda.

93. 

Bergen, The Longest War, p. 248.

94. 

Ibid., pp. 255–256. The North-West Frontier Province is now known as Khyber Pakhtunkhwa.

95. 

C. Christine Fair, Neil Malhotra, and Jacob N. Shapiro, “Islam, Militancy, and Politics in Pakistan: Insights from a National Sample,” Terrorism and Political Violence, Vol. 22, No. 4 (September 2010), pp. 495–521. For other studies that examine support for militancy in Pakistan, see C. Christine Fair, “Militant Recruitment in Pakistan: Implications for Al Qaeda and Other Organizations,” Studies in Conflict and Terrorism, Vol. 27, No. 6 (November/December 2004), pp. 489–504; and Jacob N. Shapiro and C. Christine Fair, “Understanding Support for Islamist Militancy in Pakistan,” International Security, Vol. 34, No. 3 (Winter 2009/10), pp. 179–218.

96. 

Fair, Malhotra, and Shapiro, “Islam, Militancy, and Politics in Pakistan,” p. 511.

97. 

Ibid.

98. 

See Shapiro and Fair, “Understanding Support for Islamist Militancy in Pakistan.” The conventional wisdom holds that poverty and Islamic religiosity are powerful predictors of militancy. This view has animated current policy toward Pakistan and other areas in which militancy occurs.

99. 

Shapiro and Fair, “Understanding Support for Islamist Militancy in Pakistan,” p. 83.

100. 

Mark Tessler et al., “Arab-Barometer: Public Opinion Survey Conducted in Algeria, Morocco, Jordan, Lebanon, Palestine, and Yemen, 2006–2007” (Ann Arbor, Mich.: Interuniversity Consortium for Political and Social Research, 2012). It is important to note that it is difficult to find reliable survey data in many of the areas that al-Qaida is most active and where the United States is targeting militants.

101. 

Juan C. Zarate and David A. Gordon, “The Battle for Reform with Al-Qaeda,” Washington Quarterly, Vol. 34, No. 3 (Summer 2011), pp. 103–122.

102. 

Ibid.

103. 

Scott Baldauf, “Is Al Qaeda in Yemen Connected to Al Qaeda in Somalia?” Christian Science Monitor, January 7, 2012.

104. 

Jones, “Think Again.”

105. 

Ibid.

106. 

Cronin, How Terrorism Ends, p. 182.

107. 

See Peter Bergen and Katherine Tiedemann, “The Almanac of Al Qaeda,” Foreign Policy, April 29, 2010, http://www.foreignpolicy.com/articles/2010/04/26/the_almanac_of_al_qaeda.

108. 

See Evan Harris, “CIA: At Most, 50–100 Al Qaeda in Afghanistan,” Political Punch blog, ABC News, June 27, 2010, http://blogs.abcnews.com/politicalpunch/2010/06/cia-at-most-50100-al-qaeda-in-afghanistan.html. These discrepancies among estimates of al-Qaida's size occur because scholars often measure different aspects of the organization: al-Qaida core, its network of decentralized fighters, or its affiliates. See Pape and Feldman, Cutting the Fuse, pp. 178–180.

109. 

All data on the lethality and frequency of al-Qaida attacks are from the Global Terrorism Database at the University of Maryland. See http://www.start.umd.edu/gtd/.

110. 

These numbers reflect reported incidents. Given that many of the early targeting efforts occurred covertly, the actual numbers could plausibly be higher.

111. 

I deleted this year from the graph to display more variation from year to year.

112. 

Ben Hubbard, “The Franchising of al Qaeda,” New York Times, January 25, 2014.

113. 

Vickers, however still advocates targeting as a key counterterrorism policy. See Michael Vickers, quoted in Adam Levine, “Al Qaeda Leader Killed in Pakistan,” September 15, 2011, http://security.blogs.cnn.com/2011/09/15/another-al-qaeda-leader-killed-in-pakistan/?hpt=hp_t2.

114. 

Using generation and dissemination of propaganda as a measure of al-Qaida's ability to undertake political action and violence, Megan Smith and James Igoe argue that drone strikes have not degraded al-Qaida. See Smith and Walsh, “Do Drone Strikes Degrade Al Qaeda? Evidence from Propaganda Output,” Terrorism and Political Violence, Vol. 25, No. 2 (February 2013), pp. 311–327.

115. 

See Smith and Walsh, “Do Drone Strikes Degrade Al Qaeda?”

116. 

Michael Freeman examines the difference in the effectiveness of targeting leaders with inspirational versus operational functions. See Freeman, “The Headless Horseman.”

117. 

Stephen R. David, for example, claims that targeted killings have an important revenge function for Israelis. See David, “Fatal Choices: Israel's Policy of Targeted Killing,” Mideast Security and Policy Studies No. 51(Ramat Gan, Israel: Begin-Sadat Center for Strategic Studies, Bar-Ilan University, 2002).

118. 

Hamas claims that the attacks were carried out in retaliation for Ayyash's killing. See Avery Plaw, Targeting Terrorists (Aldershot, U.K.: Ashgate, 2008), p. 167.

119. 

Khaled Hroub, “Hamas after Shaykh Yasin and Rantisti,” Journal of Palestine Studies, Vol. 33, No. 4 (Summer 2004), p. 21.

120. 

Atran, “Mishandling Suicide Terrorism.”

121. 

Bloom, Dying to Kill.

122. 

There is a considerable debate regarding the effectiveness of drone strikes, how many civilian deaths they cause, and the extent to which they influence public opinion. See Patrick B. Johnston and Anoop Sarbahi, “The Impact of U.S. Drone Strikes on Terrorism in Pakistan” (Cambridge, Mass.: Belfer Center for Science and International Affairs, Harvard Kennedy School of Government, 2011); David Kilcullen and Andrew McDonald Exum, “Death from Above, Outrage Down Below,” New York Times, May 16, 2009; Smith and Walsh, “Do Drone Strikes Degrade Al Qaeda?”; Walsh and Schmitt, “Drone Strike Killed No. 2 in Al Qaeda, U.S. Officials Say”; International Human Rights and Conflict Resolution Clinic of Stanford Law School and Global Justice Clinic at New York University School of Law, “Living under Drones: Death, Injury, and Trauma to Civilians from U.S. Drone Practices in Pakistan,” 2012, http://www.livingunderdrones.org; and International Crisis Group, “Drones: Myth and Reality in Pakistan,” Asia Report No. 247 (Brussels: International Crisis Group, 2013).

123. 

Again, there is considerable disagreement over the number of civilians or noncombatants who have been killed during drone strikes. For example, the International Crisis Group's report on drone strikes claims, “Both the international and Pakistani media often rely on figures provided by unnamed sources in the U.S government and/or Pakistani military, each with a vested interest in under- or over-reporting civilian causalities.” See International Crisis Group, “Drones,” p. 25. Pakistani journalists can also be coerced or threatened by members of Pakistan's Inter-Services Intelligence directorate and militants. C. Christine Fair has argued that the number of civilian casualties in drone strikes has been overreported. See Fair, “Drone Wars,” Foreign Policy, May 28, 2010; and Fair, “For Now, Drones Are the Best Option,” New York Times, January 29, 2013. There is also disagreement over what constitutes a civilian or a combatant. The Pakistani military, for example, considers civilians who harbor Taliban militants to be militants themselves. It also considers civilians who have not fled a conflict zone ahead of a military operation to be militant sympathizers and thus targets. The U.S. government argues that all military-age men killed in a strike zone are militants, unless proven otherwise. Despite considerable differences among existing drone strikes databases, all show a decline in the number of civilian deaths since 2011. Two more recent studies look at specific drone strikes to address some of the legal issues regarding civilian casualties. See Amnesty International, “‘Will I Be Next?’ U.S. Drone Strikes in Pakistan” (London: Amnesty International, 2013); and Human Rights Watch, “‘Between a Drone and Al Qaeda’: The Civilian Cost of U.S. Targeted Killings in Yemen” (New York: Human Rights Watch, 2013).

124. 

See International Crisis Group, “Drones,” p. 8. Kilcullen and Exum also express concern over the number of civilians injured or killed during drone strikes. See Kilcullen and Exum, “Death from Above, Outrage Down Below.”

125. 

International Human Rights and Conflict Resolution Clinic of Stanford Law School and Global Justice Clinic at New York University School of Law, “Living under Drones.”

126. 

Although support may increase, there are questions about whether it affects the ability of a group to recruit more members. The International Crisis Group's report claims, however, that drone strikes have minimal impact on recruitment. See International Crisis Group, “Drones.”

127. 

For research on issues related to the legality of drones strikes, see Mary Ellen O'Connell, “Seductive Drones: Learning from a Decade of Lethal Operations,” Journal of Law, Information, and Science, Vol. 21, No. 2 (August 2011), pp. 1–27; and Michael L. Gross, “Fighting by Other Means in the Mideast: A Critical Analysis of Israel's Assassination Policy,” Political Studies, Vol. 51, No. 2 (June 2003), pp. 350–368.

128. 

See ibid.; and Bergen, “Should We Still Fear Al Qaeda?” CNN Opinion, February 6, 2013, http://www.cnn.com/2013/02/03/opinion/bergen-al-qaeda-deadly.

129. 

Bergen, The Longest War.

130. 

Ibid., p. 547.