







































Re-Evaluating the Efficacy of Targeted Killing 

Zachary Cleary 

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Re-evaluating the Efficacy of Targeted Killing 

 

Zachary Cleary 

 

University of Illinois Urbana-Champaign 

 

 

 

 

 

 

Introduction 

The purposeful killing of select individuals is a cornerstone of modern counter-terror and 

insurgency doctrine. The CIA’s drone fleet strikes targets across the globe, while Israeli strikes 

on Hamas leadership have become so routine as to be compared to “mowing the grass” (Inbar & 

Shamir, 2014). Despite the ubiquity of targeted killing, the academic community is divided as to 

its effectiveness. This article seeks to demonstrate that, as the literature on targeted killing has 

matured and become more rigorous, the consensus has shifted from seeing targeted killings as an 

ineffective or counterproductive measure to viewing them as an effective tool. After reviewing 

the early arguments against targeted killing, this article assesses these claims in light of more 

recent research. It explores why and how targeted killings aid security forces and concludes with 

four policy lessons. 

 

 

 

 

 

 

 

 

 

 

  



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This paper uses the term “targeted killing” to refer to intentional strikes on high-value 

militants, generally leaders. The more limited term “decapitation strike” refers only to attacks on 

the most senior leader of an organization. The term “militant” is preferred to describe targets, as 

the groups this paper deals with blur the lines between insurgents and terrorists. This paper is 

restricted to concerns about the effectiveness of targeted killing as a counterterrorism and 

counterinsurgency strategy. It does not discuss the legality or morality of targeted killing. 

 Rigorous study of targeted killing is a recent phenomenon. Although targeted killing is a 

practice from time immemorial, systematic large-scale programs directed against militant groups 

are a product of the 21st century. The modern Israeli program, one of the earliest, began in 2000 

as a product of the Second Intifada (David, 2003, p. 1). The first American drone strike outside 

of a military operation was in 2002 (Sifton, 2012). 

 Early academic works on targeted killing pushed back against their already extensive use. 

Stephanie Carvin (2012) noted, “[I]t is not difficult to discern that the overwhelming number of 

empirical studies do not support the idea that targeted killings are an effective counterterrorism 

tactic” (p. 542). In this early phase, three arguments against targeted killing developed. The first 

and simplest was that it was generally ineffective. The second was that it was specifically 

ineffective against certain groups. The third was that targetted strikes create a backlash that 

outweighs any benefits. 

The first and most fundamental criticism of targeted killing is that it simply does not 

produce positive outcomes. One study on the protracted Israeli program found that targeted 

killings neither significantly increase nor decrease the level of violence (Hafez & Hatfield, 2006, 

pp. 377-378). Another work on the same program goes further and argues that strikes increase 

the expected rate of suicide bombings (Kaplan, Mintz & Mishal, 2005, pp. 232-233). Jenna 

Jordan (2009) found that groups that suffer leadership decapitation are 20 percent less likely than 

those who are not struck to be completely inactive in the two years following the strike (p. 746). 

Thus, Jordan concluded that targeting leadership is a counterproductive policy.  

 The second, more nuanced, argument concedes that targeted killing may be effective 

against some organizations. However, it contends that other militant organizations are resistant 

or even immune to the damage targeted killing inflicts due to their age, size, or ideology. Older 

organizations have had time to establish procedures, a bureaucracy, and a pool of veteran 

replacements, making the role of any one leader less vital. Jordan (2009) found that increased 

organization age reduces the likelihood of complete collapse after the death of a leader (p. 741). 

Likewise, larger groups are generally more dispersed and complicated; therefore, they may be 

more resilient when a single leader is killed. Jordan (2009) found that decapitation slightly 

increased the rate of collapse for groups up to 500 members (p. 747). However, for larger groups, 

leadership decapitation does not increase, but instead reduces the rate of collapse by up to 46 

percent. Thus, Jordan concludes that against any substantive foe, decapitation is 

counterproductive. Lastly, some argue that certain ideologies confer increased organizational 

resilience to decapitation as followers are bound together by a common cause greater than any 

one leader. Exactly which causes have this impact is debated. Jordan (2009) argues that religious 



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groups and separatist are particularly resilient to decapitation-induced collapse (p. 748). Jeremy 

Weinstein (2006) instead argue that the mass appeal of communist insurgencies makes them 

uniquely capable of absorbing the shock of decapitation (pp. 20-31). 

 The third criticism, the backlash argument, holds that the net impact of strikes is negative 

due to increased recruitment, retaliatory violence, and weakened norms that protect leaders. 

Adherents of this position argue that the outrage and collateral damage generated by strikes 

produce more recruits and support for militant groups (David, 2003, pp. 8-9). For instance, they 

hold that while Israeli strikes kill individuals, the recruits generated more than compensate for 

the few militants killed (Kaplan et al., 2005, pp. 232-233). Additionally, militant groups might 

retaliate by increasing violent activity to demonstrate strength, show defiance, and avenge the 

fallen (Byman, 2006, pp. 99-100). In her work, Carson (2017) finds that al-Qaeda responds to the 

killing of a leader with an increase in violence (p. 213). Mannes (2008) proposes that religious 

groups are likely to increase violence in response to the death of a leader, but his findings are 

inconclusive (p. 43). Steven David (2003) attempts to link four specific Israeli strikes to major 

episodes of Palestinian violence (p. 9). Carvin (2012) proposes that targeted killing weakens 

norms against killing political leaders and thus invites retaliatory assassination attempts on 

public leaders (pp. 536-537). 

This early consensus that targeted killing is at best useless, and possibly 

counterproductive, has been challenged by more recent research informed by better data, more 

realistic measures, and increasingly sophisticated analysis. Given the vanguard nature of their 

work, early authors had limited data (Carvin, 2012, p. 546). Thus, early efforts were often case 

studies or comparisons, which, due to their small scale, produce conclusions that cannot be 

generalized (Carvin, 2012, p. 547-548). Carvin (2012) acknowledges Jordan as a pioneer in 2009 

for her large dataset of 298 strikes, but she also argues that Jordan “seems to be missing the 

forest for the trees” because Jordan focused purely on individual strikes and not on campaigns (p. 

546).  Early works frequently fixated only on whether leadership removal led directly to the 

collapse of the targeted group. It is this logic that leads Jordan (2009) to conclude that targeted 

killing is a failed strategy, since it does not guarantee the disintegration of the target group within 

two years (pp. 753-754). Thus, Jordan is criticized for using unrealistically high coding standards 

of success (Johnston, 2012, p. 49; Price, 2012, p. 13). A more nuanced analysis indicates that 

decapitation strikes are correlated with increased organizational mortality rates (Price, 2012, p. 

43). Furthermore, there is evidence that successful high-level decapitation strikes increase the 

probability of government victory that year by 32 percent (Johnston, 2012, p. 63). Targeted 

killings may not guarantee victory, but they appear to increase its likelihood. 

 It may be true that some groups are more resilient than others to the effects of targeted 

killings; however, the exact characteristics that correlate with militant group durability are 

contested. The one point of consensus is that groups that depend heavily on a single highly 

charismatic leader and their cult of personality are especially vulnerable. The collapse of the 

Shining Path in Peru after its leader Manuel Guzman was captured is a classic example (Cronin, 

2009, pp. 18-19). It is logical that groups that are heavily invested or centered around the leader 



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suffer more when the leader is killed, but that is where agreement ends. Early assertions that age, 

size, or type of group are correlated with resilience to targeted killing have been qualified or 

contradicted by further research.  For instance, Johnston (2012) shows that even groups over ten 

years old suffer and are more likely to be defeated after a leader is killed (p. 74). Jordan’s 

conclusion that sufficiently large groups benefit from decapitation strikes is directly contradicted 

by Price’s (2012) latter finding that larger organizations do not fare better than smaller groups 

after a leader is killed (pp. 38-39). 

 The backlash argument remains mostly theoretical with little empirical evidence of a 

consistent trend of increased militant recruitment or material support after a leader is killed. 

While targeted killing is often unpopular in the target area, it does not appear that such 

sentiments translate to increased militant membership or mobilization (Johnston & Sarbahi, 

2016, pp. 211-212). If there was a backlash effect, it should be particularly visible after a failed 

strike. In such a scenario, the negative impacts of a strike, such as civilian casualties, would 

occur and there would be no actual damage to the militant organization. Yet, research shows no 

significant increase in conflict intensity or the number of attacks after failed attempts to kill 

leaders (Johnston, 2012, p. 68). Nor has Carson’s (2017) argument that militant groups will 

retaliate and increase violence in response to strikes been substantiated (Hafez & Hatfield, 2006, 

p. 378). Instead, Carson has been criticized for overstating the implications of statistically weak 

results gleaned from only ten data points (Forst, 2017, p. 222). As Forst (2017) rightly notes, 

“Failure to find is not at all the same as a finding of failure.” (p. 222). Instead, as will be 

discussed below, the balance of evidence suggests that strikes reduce militant violence. 

 Later research has generally contradicted earlier efforts and indicates that targeted killing 

is, in fact, effective. Thus, the logical next question is, “why?” The simplest reason is that 

targeted killing programs degrade militant leadership. Militant groups have limited recruitment 

pools and few skilled leaders. Eventually, a sustained program will eliminate the most competent 

leaders the militant group has. When leaders are replaced by less talented replacements, the 

group suffers (Johnston, 2012, p. 52). For an illustrative example, when Abu Musab al-Zarqawi 

of al-Qaeda in Iraq (AQI) was killed, his replacement, Abu Ayyub al-Masri, was a far less 

effective leader and his tenure marked a low point for al-Qaeda in Iraq. More generally, targeted 

killing programs often seek to neutralize other militant specialists beyond just leaders. Militant 

groups have limited numbers of skilled members such as bombmakers and forgers (Byman, 

2006, p. 103). Eliminating these individuals degrades the entire organization’s capabilities. 

Specialists must be trained, they cannot be replaced by generic recruits (Byman, 2006, pp. 103-

104). Even if a militant group has an extensive supply of talented replacements, it will still 

suffer. Each dead leader means a loss of experience and the connections that they have 

developed.  

 Targeted killings inhibit centralized control and can lead to groups splintering. Only the 

most organized militant organizations have formal succession protocols in place. The covert and 

dispersed nature of militant organizations, combined with their heavy emphasis on personal 

networks, make establishing such protocols difficult (Price, 2012, p. 18). Militant groups are not 



Re-Evaluating the Efficacy of Targeted Killing 

Zachary Cleary 

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like corporations and governments with clear and overt structures. Therefore, power transfers 

and successions are often fraught for militant organizations. Leadership turnover increases the 

likelihood of the group collapsing and killing leaders has a particularly pronounced impact 

(Price, 2012, pp. 41-42). When decapitation does cause splintering, the smaller, more diffuse, 

fragments lack the capability to launch large attacks or sustained campaigns. While splintering a 

group may eliminate the possibility of a single decisive victory, such victories are rare when 

dealing with militant groups. Instead of gambling on decisive victory, it is more practical to 

fracture large militant groups and then attempting to defeat the fragments in detail.   

 Beyond the damage dealt to the organization, targeted killings suppress and disrupt 

militant violence. Regardless of other benefits, this aspect alone makes targeted killings a 

valuable tool for combatting militants. The unexpected death of a valued leader disrupts the 

regular function of the target organization and interferes with its operational capacity. In his 

analysis of 118 decapitation attempts, Johnston (2012) finds that killing a leader results in 

decreases of both the number and total lethality of attacks (p. 65). Supporting this conclusion, a 

more specific study on drone strikes in Pakistan found an approximate 25 percent decrease in 

militant lethality in the week following a strike (Johnston & Sarbahi, 2016, p. 212). Perhaps 

early theories were correct in arguing that targeted strikes induce the desire for violent 

retaliation, but they failed to appreciate the difficulties of realizing such intentions. 

These findings indicate that targeted killings not only inhibit militants’ ability to carry out 

attacks (lower volume of attacks) but leaves them unable to compensate by increasing the quality 

of attacks that are conducted (lower total lethality of attacks). Research on Palestinian reactions 

to Israeli strikes indicates that, after a strike, the number of intended attacks is not decreased, but 

fewer are successfully carried to completion (Jaeger & Paserman, 2009, p. 340). To the extent 

this finding can be generalized to other conflicts, it suggests that the lack of backlash is due to 

reduced militant capability, not diminished will.  

However, it is essential to emphasize the temporary nature of this disruption effect. 

Eventually, the militant group replaces the slain leader and returns to normal operation. The 

reduction in number and lethality of attacks is not permanent (Johnston & Sarbahi, 2016, pp. 

215-216). This general pattern of temporarily reduced violence holds in the case of the Israeli 

program (Jaeger & Paserman, 2009, p. 332). Organizations can, in time, recover from individual 

blows. Thus, constant pressure via sustained targeted killing campaign is essential.  

One product of decentralized militant command is an increase in the proportion of 

indiscriminate attacks against civilians instead of targeted attacks on government or military 

targets. At first, this seems undesirable. One of the primary responsibilities of counterterror 

forces is the protection of civilians. However, there is a strong body of literature showing that 

indiscriminate violence targeting civilians backfires against militants and ultimately diminishes 

their prospects of victory (Abrahms & Potter, 2015, pp. 314-315). Senior militant leaders are 

aware of this trend and do their best to control such excesses (Abrahms & Mierau, 2017, p. 832). 

Senior leaders attempting to enforce restraint can be found across groups, from al-Zawahiri 

scolding Zarqawi for reveling in his prominence as “Sheikh of the Slaughterers” to PKK leader 



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Murat Karayilin directing his forces not to target civilians (Abrahms & Potter, 2015, p. 312). 

However, there is a principal-agent problem as there is a disconnect between militant leadership 

and the members who actually conduct attacks. Lower-level militants lack the perspective of 

senior leaders, may not have the capacity to easily strike military targets, and even have other 

incentives to target civilians (Abrahms & Potter, 2015, p. 316). Militant groups with a weaker, 

less centralized leadership are less able to restrain their foot soldiers and are 15 percent more 

likely to target civilians (Abrahms & Potter, 2015, p. 324).  

Targeted killings reduce leadership control and increase self-defeating indiscriminate 

attacks. Successful strikes increase the proportion of violence against civilians by seven percent 

and the act of attempting a strike alone increases the probability by 6.5 percent (Abrahms & 

Potter, 2015, p. 328). This indicates that the presence of an active targeted killing campaign 

forces leaders to take security measures that inhibit their ability to control their organization. It is 

important to note that this pressure only increases the likelihood of attacks against civilians; it 

does not reduce attacks on military targets (Abrahms & Potter, 2015, p. 329).  Security measures 

may leave the leader less able to restrain their forces, but still capable of directing attacks on 

military targets. However, successful strikes both increase the chance of attacks against civilians 

and decrease that of attacking military targets (Abrahms & Potter, 2015, p. 329). This suggests 

that killing a militant group’s leader degrades the group’s striking capability, so they are forced 

to settle for less difficult targets. Notably, there is brief delay before the reduction in attacks 

against military targets as plans in place before the attack are carried out (Abrahms & Potter, 

2015, p. 330). The disruption to the militant group’s operations becomes fully apparent once new 

directions or planning is required. Further studies have confirmed that militant groups engage in 

more indiscriminate attacks against civilians in the two weeks after a leader is killed (Abrahms & 

Mierau, 2017, p. 837). There is evidence that the increase is also not permanent and attacks on 

civilians return to normal levels eventually (Abrahms & Mierau, 2017, p. 845). As new leaders 

reassert control, discipline is once again imposed on the lower ranks. This ability to recoup from 

any individual strike further emphasizes the importance of a sustained targeted killing campaign 

instead of occasional strikes.  

 While the consensus on the efficacy of targeted killing has shifted, it is premature to 

declare the issue concluded. There is still much left unsettled and underspecified, and thus, this 

article echoes those cited in its call for further research. The direct causal links between strikes, 

loss of militant leadership, and increased proportion of attacks on civilian targets must be better 

established. How long the impact of a strike lingers remains unclear. There is no research on 

whether the effects of successive strikes are cumulative or independent. Nonetheless, while more 

research is needed, we can draw four valuable policy lessons from what has been done. First, 

targeted killing is probably not counterproductive. Second, there is utility in killing targets other 

than the primary leader. The death of mid-level leadership and specialists also disrupts militant 

operations. Third, sporadic strikes are insufficient since some of the most important impacts are 

temporary. Thus, a constant campaign is desirable. Fourth, states that engage in targeted killing 

should be aware of the increased likelihood of civilian deaths and be prepared for them. 



Re-Evaluating the Efficacy of Targeted Killing 

Zachary Cleary 

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 There is truth in the maxim that you cannot kill your way to victory in counterinsurgency. 

However, neither can there be a successful counterinsurgency operation without violence. 

Targeted killings are a further extension of that theme. A targeted killing campaign degrades 

militant leadership, inhibits coordination, induces self-defeating acts, and suppresses violence. 

The value of a sustained targeted killing campaign is the space that it creates for nation-building 

and the difficult tasks that do defeat militant groups. 

 

 

 

 

  



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http://www.jpost.com/Opinion/Columnists/Mowing-the-grass-in-Gaza-368516

