Targeting of militant
leaders is central to many states’ national security strategies, but does it
work? What should policymakers expect when armed forces capture or kill
militant leaders? Is leadership decapitation more likely to succeed or fail under
certain conditions? These questions have never been more pressing than
after the May 2011 killing of al-Qaida leader Osama bin Laden. As relevant as
these questions are to current U.S. policy and strategy, they are also fundamental
questions of asymmetric warfare. They matter because almost all policies of
“high-value” targeting require difªcult judgments concerning both the potential
consequences and the opportunity costs of targeting militant leaders. The
decision to target enemy leaders requires that policymakers adjudicate among
numerous difªcult, and potentially contradictory, choices. Leadership targeting
strategies affect how states allocate scarce military, intelligence, and
economic resources; how they construct their counterinsurgency or counterterrorism
postures; and how interested foreign and domestic audiences react to
their behavior.
Despite the stakes, scholars have shown relatively little interest in leadership
decapitation. Those who have written on the topic have tended to argue
that leadership targeting is ineffectual and can be counterproductive.1
TarDoes
Decapitation Work?
Does Decapitation
Work?
Patrick B. Johnston
Assessing the Effectiveness of Leadership
Targeting in Counterinsurgency
Campaigns
Patrick B. Johnston is Associate Political Scientist at the RAND Corporation. He wrote this article while he
was a fellow at the Center for International Security and Cooperation and the Empirical Studies of Conºict
Project at Stanford University and at the International Security Program at Harvard Kennedy School’s
Belfer Center for Science and International Affairs. A supplemental appendix is available online at http://
patrickjohnston.info.
The author would like to thank Max Abrahms, Mia Bloom, Stephanie Carvin, Martha Crenshaw,
Lynn Eden, James Fearon, Joseph Felter, Bryan Price, William Reno, Anoop Sarbahi, Paul
Staniland, David Steinberg, and the anonymous reviewers for commenting on earlier versions of
this article.
1. Robert A. Pape, Bombing to Win: Air Power and Coercion in War (Ithaca, N.Y.: Cornell University
Press, 1996); Robert A. Pape, “The Strategic Logic of Suicide Terrorism,” American Political Science
Review, Vol. 97, No. 3 (August 2003), pp. 1–19; Stephen T. Hosmer, Operations against Enemy Leaders
(Santa Monica, Calif.: RAND, 2001); Paul Staniland, “Defeating Transnational Insurgencies: The
Best Offense Is a Good Fence,” Washington Quarterly, Vol. 29, No. 1 (Winter 2005/06), pp. 21–40;
Mohammed M. Hafez and Joseph M. Hatªeld, “Do Targeted Assassinations Work? A Multivariate
Analysis of Israel’s Controversial Tactic during Al-Aqsa Uprising,” Studies in Conºict and Terrorism,
Vol. 29, No. 4 (June 2006), pp. 359–382; Or Honig, “Explaining Israel’s Misuse of Strategic AssassiInternational
Security, Vol. 36, No. 4 (Spring 2012), pp. 47–79
© 2012 by the President and Fellows of Harvard College and the Massachusetts Institute of Technology.
47
geting enemy leaders, argues Robert Pape, “has never been effective” as a
coercive tool in interstate war.2
Decapitating terrorist organizations is not effective
either, according to Pape, whose high-proªle study of suicide terrorism
concludes that decapitation strategies “have met with meager success.”3
Jenna
Jordan’s recent study supports Pape’s earlier conclusion. Terrorist organizations
rarely collapse after their top leaders are captured or killed, she ªnds.
Jordan concludes that leadership decapitation is “a misguided strategy.”4
This consensus is premature. Researchers have conducted few systematic assessments
of leadership decapitation’s effectiveness; evidence remains scant.5
But contrary to scholars’ claims that leadership decapitation never works, the
evidence appears to be more mixed. In numerous cases, decapitation was vital
in degrading and defeating militant groups. In Peru, for example, Shining Path
leader Abimeal Guzmán’s 1992 capture crippled the group’s bid for power. In
Turkey, the capture of Abdullah Ocalan, leader of the Kurdistan People’s Party,
in 1999 precipitated the group’s steep decline. And in Italy, authorities used
critical intelligence obtained from captured Red Brigades leaders to dismantle
remnants of the organization.6
Moreover, the research design and methodologies used in nearly all previous
studies make it difªcult to draw credible conclusions about the impact of
leadership decapitation. Three problems are common in the literature. First,
the security studies literature, for example, relies uniformly on no-variance de-
signs.7
Yet credible causal inferences cannot be made from studies that only
International Security 36:4 48
nations,” Studies in Conºict and Terrorism, Vol. 30, No. 6 (June 2007), pp. 563–577; and Jenna Jordan,
“When Heads Roll: Assessing the Effectiveness of Leadership Decapitation,” Security Studies,
Vol. 18, No. 4 (December 2009), pp. 719–755. At least one study suggests that decapitation is effective.
See Bryan Price, “Removing the Devil You Know: Unraveling the Puzzle behind Decapitation
Effectiveness and Terrorist Group Duration,” Ph.D. dissertation, Stanford University, 2009. Several
authors suggest that decapitation’s impact is conditional on other factors. See, for example, Daniel
Byman, “Do Targeted Killings Work?” Foreign Affairs, Vol. 85, No. 2 (April 2006), pp. 95–111; Daniel
Byman, A High Price: The Triumphs and Failures of Israeli Counterterrorism (New York: Oxford University
Press, 2011); Matt Frankel, “The ABCs of HVT: Key Lessons from High Value Targeting
Campaigns against Insurgents and Terrorists,” Studies in Conºict and Terrorism, Vol. 34, No. 1 (January
2010), pp. 17–30; and Austin Long, “Assessing the Success of Leadership Targeting,” CTC Sentinel,
Vol. 3, Nos. 11/12 (November 2010), pp. 19–21.
2. Pape, Bombing to Win, p. 316.
3. Pape, “The Strategic Logic of Suicide Terrorism,” p. 14.
4. Jordan, “When Heads Roll,” p. 754.
5. Few large-n studies of leadership decapitation exist. See Jordan, “When Heads Roll”; Price, “Removing
the Devil You Know”; and Patrick Johnston, “The Effectiveness of Leadership Decapitation
in Counterinsurgency,” paper presented at CISAC Social Science Seminar, Stanford
University, May 2009.
6. In addition, Aaron Mannes’s medium-n study found “some indication that decapitation strikes
can be effective in reducing terrorist group incidents.” Mannes’s results, however, were not statistically
signiªcant. Mannes, “Testing the Snake Head Theory: Does Killing or Capturing Its Leaders
Reduce a Terrorist Group’s Activity?” Journal of International Policy Solutions, Vol. 9 (Spring 2008),
pp. 43–44.
7. A notable exception, published in the economics literature, is Benjamin Jones and Benjamin
examine cases in which opposing leaders were captured or killed. Second,
scholars have tended to use extremely restrictive coding criteria, setting the
bar unrealistically high for decapitation to be considered successful; except in
cases where the target was quickly and decisively defeated following a
leader’s capture or death, scholars have usually coded decapitation as a failure.
This is appropriate for evaluating decapitation’s proximate strategic impact,
but it is inappropriate for assessing decapitation’s longer-term political,
military, and economic effects. Decapitation could have a wide variety of
effects—some positive, others potentially negative—that this approach does
not capture.8
A second problem is selection bias. Militant leaders tend to be
killed or captured at key junctures in campaigns—periods when governments
may already be more likely to win or lose.9
Security studies scholarship on
leadership decapitation—including large-N studies—fails to address this issue,
which makes it difªcult to identify whether decapitation explains the outcomes
of interest, or whether other factors that make decapitation more likely
to occur actually drive the relationship. This challenge is daunting, both for
quantitative and qualitative studies that rely on observational data. An experimental
design would solve this problem, but for many of the most important
security studies questions, especially the present one, an experiment is neither
desirable nor feasible. In these situations, scholars can instead exploit research
designs that focus on data where confounding factors are unlikely to cause
misleading correlations. Doing so helps scholars to isolate their variable(s) of
interest and to avoid making conclusions and policy recommendations based
on spurious, misleading ªndings.
This article addresses these challenges by analyzing a large number of cases
in which governments attempted—successfully and unsuccessfully—to remove
top militant leaders and the events that followed these attempts.10
This
approach relies on a natural experiment to help isolate the importance of militant
leaders. To the extent that chance plays a role in the outcome of operations
aimed at removing military leaders, this approach can help researchers assess
the likelihood that organizations whose leaders were captured or killed would
have fared differently had their leadership remained intact.
Does Decapitation Work? 49
Olken, “Hit or Miss? The Effect of Assassinations on Institutions and War,” American Economic
Journal: Macroeconomics, Vol. 1, No. 2 (July 2009), pp. 55–87.
8. This hypothesis is key to policy and doctrine, which prescribe leadership targeting as part of a
general strategy to reduce the threat of militant attacks by degrading the organizational capacity
of militants to conduct large-scale operations.
9. James D. Fearon and David D. Laitin, “Civil War Termination,” unpublished manuscript, Stanford
University, 2008, pp. 39–42; and Jones and Olken, “Hit or Miss?”
10. For a similar approach to studying the effects of national leaders on economic growth, democratization,
and war, see Benjamin Jones and Benjamin Olken, “Do Leaders Matter? National Leadership
and Growth since World War II,” Quarterly Journal of Economics, Vol. 120, No. 3 (August
2005), pp. 835–864; and Jones and Olken, “Hit or Miss?”
This approach is valid for identifying the effect of leadership decapitation as
long as decapitation operations’ outcomes are not systematically determined
by factors unaccounted for in the analysis. This assumption holds up to both
anecdotal and systematic scrutiny. As I argue below, the clandestine nature
of militant leadership and unforeseen or idiosyncratic circumstances can compromise
the chances of even the most well planned operations to succeed.
Large-N scrutiny supports this argument. Analysis of 118 decapitation attempts
from a sample of 90 counterinsurgency campaigns shows that factors
commonly associated with counterinsurgency success generally fail to predict
the success or failure of government actions to remove militant leaders.
My results challenge previous claims that removing militant leaders is ineffective
or counterproductive. On the contrary, they suggest that leadership decapitation
(1) increases the chances of war termination; (2) increases the
probability of government victory; (3) reduces the intensity of militant violence;
and (4) reduces the frequency of insurgent attacks.
It is important that the ªndings be interpreted with care and in light of their
limitations. Although the estimated impact of decapitation is substantial, decapitation
is not a silver bullet. A better interpretation is that, although decapitation
is likely to help states’ overall efforts against militant organizations,
other factors will also matter greatly in most cases.11
In other words, decapitation
is more likely to help states achieve their objectives as an operational component
within an integrated campaign strategy than as a stand-alone strategy
against insurgent and terrorist organizations.
The article proceeds as follows. First, I describe and critique the argument
that leadership decapitation is ineffective. Second, I describe my dataset, variables,
and key summary statistics. Third, I discuss my empirical methodology.
I begin by presenting evidence that decapitation attempt outcomes are plausibly
exogenous. Then I describe my estimation strategy for identifying the effects
of leadership decapitation. Fourth, I present the main results of my
analysis. I conclude the article by recapitulating my primary ªndings and discussing
their policy implications.
The Notion That Leadership Decapitation Does Not Work
Claims that leadership decapitation is ineffective or counterproductive usually
rest on three premises: organizational durability, martyrdom effects, and decentralizing
effects. I examine each premise in turn.
International Security 36:4 50
11. Matt Frankel emphasizes this point in his research on high-value targeting. Frankel, “The
ABCs of HVT,” pp. 20, 28. For an in-depth example of how integrating leadership targeting with
organizational durability
Individuals—including leaders—rarely factor signiªcantly into leading theories
of insurgency and counterinsurgency, which instead emphasize the civilian
population’s importance.12
These theories suggest that a multifaceted array
of actors, institutions, and structures, which are rooted deeply in society, make
up insurgent organizations. Such social organizations are likely to be highly
durable and larger than any individual or set of individuals. It follows from
the theories, then, that removing key individuals is unlikely to undermine insurgency;
effectively undermining insurgency requires the removal of societal
support.
Assuming that insurgent organizations are resilient to the loss of individual
leaders holds intuitive appeal, especially when considering high-proªle movements
such as the National Liberation Front in Algeria or the Vietcong, but the
assumption’s applicability to the wider universe of insurgencies is questionable.
It is not unreasonable to think that many guerrilla groups would lack the
robust structures necessary to insulate themselves from the shocks associated
with the loss of key leaders. The Janatha Vimukthi Peramuna (JVP), for example,
a communist insurgency that staged uprisings against the Sri Lankan government
in 1971 and 1987, suffered greatly in each conºict after Sri Lankan
authorities captured its leader, Rohana Wijeweera, who masterminded the
group’s overall strategy and tactical operations. In both conºicts, the JVP relied
heavily on Wijeweera’s operational skills and charisma. After his capture,
Wijeweera’s subordinate commanders failed to execute the operations he had
planned in each subsequent campaign, and the JVP was quickly defeated.13
Palestinian Islamic Jihad (PIJ) leader Fathi Shaqaqi was similarly crucial to his
organization’s cohesion and operational capabilities.14
It is therefore unsurprising
that Shaqaqi’s 1995 assassination—allegedly by Israeli agents—dealt
the PIJ a severe blow.15
Finally, even though scholars correctly observe that leadership decapitation
is rarely a silver bullet solution to insurgency, this does not mean that killing or
Does Decapitation Work? 51
other countermilitancy policies can enhance government campaign effectiveness, see Byman, “Do
Targeted Killings Work?” pp. 105–106.
12. Mao Zedong, On Guerrilla Warfare (New York: Praeger, 1961); David Galula, Counterinsurgency
Warfare: Theory and Practice (Westport, Conn.: Praeger Security International, 1964); and the U.S.
Army and Marine Corps, The U.S. Army/Marine Corps Counterinsurgency Field Manual, FM 3-24
(Chicago, Ill.: University of Chicago Press, 2007).
13. S. Arasaratnam, “The Ceylon Insurrection of April 1971: Some Causes and Consequences,”
Paciªc Affairs, Vol. 45, No. 3 (Autumn 1972), pp. 356–371.
14. Steven R. David, “Fatal Choices: Israel’s Policy of Targeted Killing,” in Efraim Inbar, ed., Democracies
and Small Wars (London: Frank Cass, 2003), p. 6.
15. For more detail, see the organizational proªle of PIJ on the website of the National Consortium
for the Study of Terrorism and Responses to Terrorism (START), http://www.start.umd.edu/
start/data_collections/tops/terrorist_organization_proªle.asp?idϭ82.
capturing an insurgency’s leadership cannot diminish insurgencies’ organizational
capabilities and effectiveness. On the contrary, removing key leaders
might have important effects, such as degrading insurgencies’ pool of skilled
commanders, strategists and operatives; disrupting insurgents’ planning,
training, and execution of operations and attacks; and, by putting remaining
insurgents on the defensive, assisting government forces in seizing or maintaining
the tactical and operational initiative.
martyrdom effects
A popular assumption is that costly “martyrdom effects” are a consequence of
capturing or killing top militant leaders.16
Instead of degrading groups’ morale
and esprit de corps, decapitation increases insurgents’ resolve, aids their
recruitment efforts, and intensiªes their desire to use violence in retaliation for
state actions.17
Jordan, for example, argues that “going after the leader may
strengthen a terrorist group’s resolve, result in retaliatory attacks, increase
public sympathy for the organization, or produce more lethal attacks.”18
While the commonly held view of insurgents and terrorists as irrational fanatics
makes the martyrdom argument seductive, there are two problems with
it. First, it tacitly assumes that insurgent leaders are popular and that their removal
will be unwelcome among subordinate members of the organization
and the population at large. Yet it can be these very actors who covertly provide
the intelligence used by governments to target insurgent or terrorist lead-
ers.19
This fact suggests that militant leaders who are targeted may be less
popular among key followers than the martyrdom theory would suggest.
Second, the martyrdom argument rests on the premise that emotions are the
primary driver of insurgent behavior. This claim clashes with leading scholarship
on insurgency, which suggests that militants are likely to make difªcult
choices on the basis of strategic calculation rather than on emotion alone.20
International Security 36:4 52
16. Byman, “Do Targeted Killings Work?” pp. 99–100; and David, “Fatal Choices,” pp. 8–9.
17. Catherine Lotrionte, “When to Target Leaders,” Washington Quarterly, Vol. 26, No. 3 (Summer
2003), pp. 73–86; Edward H. Kaplan, Alex Mintz, Shaul Mishal, and Claudio Samban, “What Happened
to Suicide Bombings in Israel? Insights from a Terror Stock Model,” Studies in Conºict and
Terrorism, Vol. 28, No. 3 (August 2005), pp. 225–235; and Jordan, “When Heads Roll,” pp. 82–83.
18. Jordan, “When Heads Roll,” p. 755.
19. See Johnston, “The Effectiveness of Leadership Decapitation in Counterinsurgency,” p. 8.
20. On strategic decisionmaking in insurgency, see especially Stathis N. Kalyvas, The Logic of Violence
in Civil War (New York: Cambridge University Press, 2006); Jeremy M. Weinstein, Inside Rebellion:
The Political Economy of Rebel Organization (New York: Cambridge University Press, 2006);
Roger D. Petersen, Understanding Ethnic Violence: Fear, Hatred, and Resentment in Twentieth-Century
Eastern Europe (New York: Cambridge University Press, 2002); Elisabeth J. Wood, Insurgent Collective
Action and Civil War in El Salvador (New York: Cambridge University Press, 2003); and Rogers
Brubaker and David D. Laitin, “Ethnic and Nationalist Violence,” Annual Review of Sociology,
Vol. 24 (August 1998), pp. 423–452.
So while the killing or capture of a guerrilla leader can lead to public outcries
from his supporters, it can also signal to the insurgency’s potential recruits
and ascendant leadership that the incumbent possesses signiªcant
strength and intelligence capabilities, possibly deterring additional mobilization
for insurgency.21
inadvertent decentralization
Third, analysts have suggested that leadership decapitation makes defeating
insurgencies more difªcult by decentralizing them.22
The assumption is that,
as organizations become less hierarchical, they evolve into localized cells capable
of persisting long after other parts of the organization have been neutral-
ized.23
Yet there is little empirical evidence that decapitation ºattens militant
organizational structures or that decentralized groups are more resilient to
state countermeasures. On the contrary, the opposite hypothesis is plausible:
even if decapitation does induce decentralized militant organization—
characterized by small cells with limited contact or knowledge of one
another—the net effect of these dynamics may be a weakening of the organization
that results from the difªculty or insecurity of movement and communications
among various cells, which makes organizing the large-scale
collective action necessary to conduct persistent, sophisticated attacks much
more difªcult.
In the next section, I discuss the dataset and variables used in the empirical
analysis.
Data
This article focuses on attempted removals of insurgent leaders in counterinsurgency
campaigns, where the “leader” is deªned as the most powerful
ªgure or ªgures in an insurgent organization. My focus is necessarily limited
to top leaders; systematically identifying and distinguishing among upperDoes
Decapitation Work? 53
21. Alexandre S. Wilner, “Targeted Killings in Afghanistan: Measuring Coercion and Deterrence
in Counterterrorism and Counterinsurgency,” Studies in Conºict and Terrorism, Vol. 33, No. 4 (April
2010), pp. 307–329.
22. For examples of this dynamic, see Byman, “Do Targeted Killings Work?” pp. 100–101; and David,
“Fatal Choices,” p. 8.
23. On this general dynamic in terrorist organizations and its implications for counterterrorism,
see Marc Sageman, Leaderless Jihad: Terror Networks in the Twenty-First Century (Philadelphia: University
of Pennsylvania Press, 2008). See also Bruce Hoffman, “The Myth of Grass-Roots Terrorism,”
Foreign Affairs, Vol. 87, No. 3 (May/June 2008), pp. 133–138. On organizational forms and
leadership decapitation in counterterrorism, see Audrey Kurth Cronin, “How al-Qaida Ends: The
Decline and Demise of Terrorist Groups,” International Security, Vol. 31, No. 1 (Summer 2006),
pp. 7–48; and Jordan, “When Heads Roll.”
echelon, midtier, and low-level leaders in clandestine organizations is prohibitively
difªcult. By contrast, the relative visibility of top leaders enables their
identiªcation in a way that minimizes measurement error that could lead to
misleading results. Focusing on top leaders is further justiªed by practical aspects
of my research question. Because top leaders are the most important
members of insurgent organizations and the highest-priority targets of antiinsurgent
operations, the most urgent ªrst-order issue, for both scholars and
policymakers, is to identify whether removing these speciªc individuals matters
for key outcomes of interest in counterinsurgency.24
dataset
To collect the data necessary for this study, I compiled a list of insurgent leaders
from the START Terrorist Organization Proªles (TOPS) database at the
University of Maryland.25
Having identiªed the top group leader or leaders, I
then collected data on leadership decapitation from the Lexis-Nexis Academic
Universe database.26
I performed keyword searches on the entire collection of
English-language news sources and reviewed the results for information on
leadership removals and attempted removals. I cross-validated each attempt
identiªed in the search results with at least one additional source before tagging
it for inclusion in the dataset.
I restricted my data collection to plausibly exogenous attempts to kill or capture
insurgent leaders. Examples of plausibly exogenous decapitation events
include attempts to remove leaders through assassination plots in which
bombs are planted or shots are ªred; combat operations in which ªreªghts or
air strikes directly target leaders’ units; and raids or sweeps of leaders’ compounds
or camp areas. Rumored plots that never materialized, and operations
in which leaders escaped before an attempt was made, are not plausibly exogenous
and were excluded. For each attempt that satisªed these criteria, I
coded the date, location, attempt type, and outcome. After ªltering the data
through these criteria, I was able to document 118 attempts. Forty-six of the
118 attempts (39%) resulted in the removal of a top-level insurgent leader.
A potential concern is that failed attempts are underrepresented in the
International Security 36:4 54
24. Future research is necessary to address second-order questions about the impact of removing
upper-echelon and midtier insurgents and terrorists from militant organizations. Targeting the
middle ranks of insurgencies has indeed been key to Israeli counterterrorism strategy as well as to
U.S. operations in Afghanistan and Iraq.
25. The TOPS database contains information on the top leader or leaders of most of the insurgencies
in my sample. I coded group leaders who were not identiªed in the TOPS database using historical
encyclopedias and secondary sources. See the database online at http://www.start.umd
.edu/start/data_collections/tops/.
26. The Lexis-Nexis website is accessible at http://www.lexisnexis.com/.
dataset. One might expect, for example, that failed attempts are underreported
because concealing them might be in the government’s interest. Upon closer
examination, however, theoretical and methodological considerations mitigate
this issue. Theoretically, it is likely that insurgent groups would have a similar
interest in revealing governments’ unsuccessful attempts. Uncovering failed
attempts might, for example, feed into insurgent propaganda by demonstrating
the government’s incompetence and unscrupulous behavior while making
insurgent leaders appear cleverer than government forces and occupants of
the moral high ground. As a result, even if governments would prefer to conceal
unsuccessful attempts, countervailing messaging by insurgents is likely to
thwart their efforts. Methodologically, even if instances of failure are missing
from the dataset, it would reduce the precision of my regression estimates’
standard errors but not undermine causal identiªcation unless a narrow set of
unlikely circumstances were to obtain—namely, if the likelihood of failing to
observe decapitation attempts was systematically higher around periods when
changes in the dependent variable are observed. This is unlikely given that
(1) the data are drawn from news reports, and (2) media reporting tends to be
most intense during critical periods of campaigns captured by my dependent
variables. In fact, it is possible that if any reporting bias does exist, it occurs
during periods when change is not observed on the dependent variables.
This would bias my estimates downward, not upward. Another consideration
is whether reporting differs by regime type given variations in press freedom.
A “counterinsurgency campaign” refers to a military contest between a state
and a nonstate actor or actors that employed a strategy of guerrilla warfare.
Following leading scholarship on insurgency and counterinsurgency, I deªne
“guerrilla warfare” as a strategy of armed resistance in which small, mobile
bands inºict violence using unconventional military tactics while avoiding direct
battle when possible and operating among the civilian population.27
I used four criteria to identify appropriate campaigns for analysis. The ªrst
is asymmetric conventional capabilities. Power asymmetries can be observed
when the relative sophistication and lethality of counterinsurgent forces’
Does Decapitation Work? 55
27. See, for example, James D. Fearon and David D. Laitin, “Ethnicity, Insurgency, and Civil War,”
American Political Science Review, Vol. 97, No. 1 (February 2003), pp. 75–90; Benjamin Valentino,
Paul Huth, and Dylan Balch-Lindsay, “‘Draining the Sea’: Mass Killing and Guerrilla Warfare,” International
Organization, Vol. 58, No. 2 (April 2004), pp. 375–407; Weinstein, Inside Rebellion; Jason
Lyall and Isaiah Wilson III, “Rage against the Machines: Explaining Outcomes in Counterinsurgency
Wars,” International Organization, Vol. 63, No. 1 (Winter 2009) pp. 67–106; Jason Lyall, “Do
Democracies Make Inferior Counterinsurgents? Reassessing Democracy’s Impact on War Outcomes
and Duration,” International Organization, Vol. 64, No. 1 (Winter 2010), pp. 10–16; and
Stathis N. Kalyvas and Laia Balcells, “International System and Technologies of Rebellion: How
the End of the Cold War Shaped Internal Conºict,” American Political Science Review, Vol. 104, No. 3
(August 2010), pp. 415–429.
weapons or other war-ªghting technologies are more sophisticated than those
used by insurgents. Second, insurgents using guerrilla warfare typically operate
within the civilian population rather than on a battleªeld separate from the
populace. Although it is difªcult to discern whether insurgents actually seek
uncoerced popular support, observing whether militant organizations implant
themselves in the civilian population is easier. The third criterion is tactical
mismatch. Unlike the raison d’être of the regular armies dispatched to suppress
them, insurgencies rely on unconventional military tactics, such as ambushes,
hit-and-run attacks, and sabotage to pursue their objectives. Militants
must be observed using these tactics while generally avoiding direct battle to
qualify for inclusion in the dataset. The ªnal operational criterion is a onemonth
minimum duration rule. These criteria help ensure that all campaigns
in the dataset were sustained, asymmetric violent conºicts between organized
military actors, not brief, disorganized bursts of violence or instances of rioting.
Campaigns that failed to satisfy each criterion were excluded from the
analysis. In all, I identiªed 90 campaigns from 1975 to 2003 that satisªed these
criteria.28
In total, the dataset contains 928 campaign-year observations, a sufªcient
number to detect statistical effects.
To estimate the effect of leadership decapitation on counterinsurgency
campaign outcomes and dynamics, I used two types of measures. The ªrst involves
campaign outcomes, which come from the Correlates of War (COW)
project.29
I examined campaign outcomes in two ways: termination and success.
Termination is a dummy variable, where “1” indicates that the campaign
dropped below a minimal threshold of violence in a given campaign-year.
Success is also measured as a dummy variable, where “1” indicates that a campaign
ended on terms favorable to the counterinsurgent in a given campaignyear
and “0” indicates that it did not.
The second type of measure involves conºict dynamics. These data come
from the Global Terrorism Database.30
I also examined conºict dynamics in
two ways: conºict intensity and insurgent-initiated incidents. Conºict intensity
measures the total number of conªrmed fatalities, by group, in each
International Security 36:4 56
28. My analysis is limited to campaigns from 1975 to 2003 because extending the analysis as far
back as 1945—the standard start date of several leading civil wars datasets—would likely produce
signiªcant undercounts of the “failure” variable, as less public information is available prior to the
mid-1970s, when an expanded global news media and new restrictions on secrecy and covert operations
led to more reporting of state attempts to remove leaders of both states and insurgent
organizations.
29. For campaigns not in the COW project data, I consulted Jason Lyall and Isaiah Wilson III,
“Correlates of Insurgency” dataset, 2009; the Global Terrorism Database; and other secondary
sources.
30. For full documentation, see the GTD codebook, p. 21, http://www.start.umd.edu/gtd/
downloads/Codebook.pdf.
campaign-year. This variable proxies overall conºict violence and insurgent
lethality.31
Insurgent-initiated incidents measures the number of attacks and
other violent incidents, by group, aggregated to the campaign-year level.32
This variable proxies insurgent groups’ levels of activity and operational tempos.
Taken together, these variables enabled me to test how leadership decapitation
affects both the lethality and rate of insurgent activities.
summary statistics
Table 1 provides summary statistics about decapitation attempts. With regard
to the manner in which attempts have been conducted, combat operations
have been the most common, comprising 34 percent of attempts, and shootings
the second most common, used in 29 percent of attempts. Attempts that
occurred in combat operations succeeded at removing insurgent leaders in
32 percent of the cases, and shooting attempts succeeded in 44 percent of the
cases. Raids and sweep operations have the highest success rate, at 64 percent,
and attempts to kill leaders using bombs and other explosive devices appear to
be particularly ineffective, as they succeeded in only 29 percent of the cases.
Full summary statistics can be found in the online appendix.33
Does Decapitation Work? 57
31. Because this variable includes government, civilian, and insurgent deaths, it is not a direct
measure of insurgent violence. Although one should expect the conºict intensity variable to be
noisy, it should still provide insight into whether removing insurgent leaders has a causal effect on
conºict escalation or de-escalation because successful and failed attempts should not be correlated
with observed or unobserved variables.
32. See the GTD codebook, p. 42.
33. The summary statistics include probabilities of transition from ongoing conºict to war termination
and ongoing conºict to government victory. Assuming no temporal dependence, the probability
of a campaign ending in a given campaign-year is about 9 percent. The probability of
government winning in a given campaign-year is about 5 percent. For violence, the average number
of people killed per campaign-year in my sample is approximately 66, and the average
number of annual insurgent attacks is 16.
Table 1. Summary Statistics: Decapitation Atttempts
Type Observations
Percentage
(total attempts)
Leader Removed
(percentage successful)
Shooting 34 29% 44%
Bombing 17 14% 29%
Raid/Sweep 25 21% 64%
Combat 41 34% 32%
Unknown 3 2% 0%
Total attempts 119 100% 40%
Figure 1 shows how the frequency of decapitation events has evolved over
time, plotting the frequency of attempts, and successful attempts, in each decade
since the 1970s by campaign-year. The ªgure indicates that both the rate of
leadership decapitation attempts and of successes increased around 2000. This
increase coincided with escalated high-value targeting efforts after the terrorist
attacks of September 11, 2001.34
Methodology
Identifying the effects of leadership decapitation is challenging. Establishing
the direction of causation is particularly difªcult, because governments might
target insurgent leaders disproportionately when they are either winning or
losing. To address this challenge, I use a large set of attempts to remove insurgent
leaders and exploit the “failures” as controls for the “successes.” My unit
of analysis is thus the outcomes of decapitation attempts rather than leaderInternational
Security 36:4 58
34. On the renewed vigor with which governments have targeted militant leaders since the September
11 attacks, see, in particular, Graham H. Turbiville Jr., Hunting Leadership Targets in Counterinsurgency
and Counterterrorist Operations: Selected Perspectives and Experience, Joint Special
Operations University, Report 07-6 (Tampa, Fla.: Joint Special Operations University Press, 2007),
pp. 8–9.
Figure 1. Attempted and Successful Decapitation Strikes
ship decapitation itself. Although the timing of decapitation strikes is not plausibly
exogenous—leaders are often targeted at key moments of campaigns
when a government is more likely either to win or to lose—the data suggest
that the success and failure of these attempts is, on average, exogenous.35
Accounts of “near misses” and “bad luck” are common in the historical record.
From the ªrst known assassination plot authorized by U.S. ofªcials
against a nonstate actor, which targeted Pancho Villa during the 1916 Punitive
Expedition, success in operations against high-value targets has been far from
a foregone conclusion. In the case of Villa, the expedition sought to eliminate
the legendary rebel for the threat he and his followers posed to American
towns in southern Texas, New Mexico, and Arizona. The United States’ manhunt
extended deep inside Mexican territory, but Villa continually evaded U.S.
forces. John Pershing, commander of the expedition, responded to these failures
by recruiting a team to inªltrate Villa’s bands and kill him. The team managed
to penetrate Villa’s camp and poison the rebel leader’s coffee during
breakfast one morning. Villa reportedly drank at least half of the laced coffee
but escaped with only minor illness.36
The United States’ failed attempt on Villa’s life foreshadowed the difªculties
that states would face in their attempts to neutralize insurgent and terrorist
leaders in the second half of the twentieth century. One example is the First
Russo-Chechen War, in which the Russian government allegedly sponsored
several failed assassination attempts against senior Chechen ofªcials. For instance,
in July 1996, Russian intelligence ofªcials were informed that Chechen
leader Dzhokar Dudayev would be chauffeured to an upcoming conference in
Moscow by a driver named Khamad Kurbanov. Based on this information,
Russian agents developed a plan to assassinate Dudayev during the Moscow
trip. The plan was put into motion weeks before the assassination was to take
place. It began when Russian police made what appeared to be a routine stop
of Kurbanov’s vehicle at a Russian-manned checkpoint inside Chechnya.
Kurbanov was brieºy taken inside a nearby ofªce for questioning. While the
police questioned Kurbanov, a team of Russian agents planted explosives under
the seats of his car. Once the explosives were in place, the Russians released
Kurbanov from questioning. Kurbanov unwittingly drove the explosive-packed
Does Decapitation Work? 59
35. The identifying assumption made in this type of research design is as follows: although attempts
to remove leaders may be driven by historical circumstances, the success or failure of decapitation
attempts can be treated as plausibly exogenous conditional on attempts taking place.
See Jones and Olken, “Hit or Miss?” p. 56.
36. Pancho Villa was ªnally assassinated in 1923. For more on this attempt, see Stephen F. Knott,
Secret and Sanctioned: Covert Operations and the American Presidency (New York: Oxford University,
1996), p. 171. See also Ward Thomas, “Norms and Security: The Case of International Assassination,”
International Security, Vol. 25, No. 1 (Summer 2000), p. 112.
vehicle without incident for weeks before Dudayev’s Moscow trip. Meanwhile,
Russian operatives prepared to detonate the explosives once Dudayev’s
presence in the vehicle could be conªrmed. Shortly before he was to ride with
Kurbanov, however, Dudayev’s itinerary changed, and he was forced to ride
with another driver. If not for this unexpected turn of events, Dudayev almost
certainly would have been killed.37
As I demonstrate below, decapitation attempts fail more often than they succeed,
and these outcomes are uncorrelated with key observable variables. As a
result, failed attempts provide an ideal set of counterfactual observations that
enable identiªcation of leadership decapitation’s causal impact.
exogeneity
Using failed attempts as controls for successes assumes that attempt outcomes
are uncorrelated with the error terms of the regression equations used to estimate
the effects of leadership decapitation. I test this assumption by putting
the independent variable on the left-hand side of the regression and examining
whether variables in my dataset predict successful attempts. The results of this
test are displayed in table 2. In column 1, the mean values of the variables are
presented. These values are all taken from the year before decapitation strikes
took place. Column 2 displays means of these variables in the year before
failed attempts; column 3 displays the differences in the means of successful
and unsuccessful decapitation attempts; and column 4 presents the results of
two-sided t-tests of the equality of these means.38
Table 2 shows that the sample of successful and failed assassination attempts
is indeed balanced across key variables: regime type; the counterinsurgent
state’s logged gross domestic product per capita; the logged population
in thousands of the counterinsurgent state; the logged average elevation of the
conºict theater in meters; and the logged distance from the counterinsurgent’s
capital city to the conºict theater in kilometers. The only variable for which
the mean difference is statistically signiªcant is the counterinsurgent nation’s
total population. The difference in means is signiªcant at the 10 percent level
(p-value ϭ 0.07). This preliminary analysis demonstrates that the possibility
that population is a confounding variable cannot be rejected.39
International Security 36:4 60
37. Gail Lapidus, “Contested Sovereignty: The Tragedy of Chechnya,” International Security,
Vol. 23, No. 1 (Summer 1998), p. 18; and Svante Cornell, Small Nations and Great Powers: A Study of
Ethnopolitical Conºict in the Caucasus (Richmond, U.K.: Curzon, 2000), p. 209.
38. These are results of t-tests that do not assume equal variance.
39. This evidence, however, is inconclusive; given that ªve variables are examined, it is not surprising
that two speciªcations were statistically signiªcant. See the supplemental table 3 in the online
appendix for additional analysis of sample balance. This analysis uses probit regressions of
attempt outcome on the variables examined in table 2 instead of t-tests. This analysis suggests that
identiªcation
To exploit the randomness in the success and failure of decapitation attempts
for causal identiªcation, my estimation strategy was to use simple OLS (ordinary
least squares) regressions that take the following form:
Yi ϭ ␤0 ϩ ␤1SUCCESSi ϩ ␥iXi ϩ εi,
where i indexes a campaign-year in which there is an decapitation attempt, Yi
is the dependent variable (campaign termination, campaign outcome, conºict
intensity, or insurgent attacks), SUCCESSi is a dummy variable equal to “1” if a
leader is captured or killed in that campaign-year and “0” if the leader escapes
any attempts, and Xi is a vector of other regressors.
The key identiªcation assumption is that, conditional on observables,
SUCCESSi is exogenous. Then, E|ε/SUCCESS,X] ϭ 0, and the average treatment
effect is:
␤1 ϭ E[Y]SUCCESS ϭ 1,X] Ϫ E[Y]SUCCESS ϭ 0,X].
This equation shows that the estimates from the OLS regression equation
written above identify the difference between successful and failed decapitaDoes
Decapitation Work? 61
once ªxed effects are added, population does not predict decapitation attempts. The results of this
analysis are similar, supporting the plausibility of the exogeneity assumption.
Table 2. Are Successful and Failed Attempts Similar? Pairwise t-Tests of Sample Balance
Success Failure Difference p-Value
Democracy ( 0.59 (0.53 0.05 0.42
(0.05) (0.04) (0.07)
Gross domestic product per capita ( 7.69 (7.7 Ϫ0.01 0.95
(0.13) (0.15) (0.2)
Population (11.13 (10.36 0.77 0.07
(0.32) (0.27) (0.42)
Military personnel ( 5.24 (4.95 0.29 0.45
(0.29) (0.25) (0.38)
Elevation (5.87 (6.09 Ϫ0.23 0.41
(0.24) (0.14) (0.27)
Distance ( 5.15 (5.35 Ϫ0.19 0.71
(0.38) (0.34) (0.51)
N (45 (58
tion attempts. If the regressions reject that ␤ is “0,” then the outcomes of bids
to decapitate insurgencies have a causal effect.
Decapitation attempts do not occur randomly, so this empirical approach
cannot conclusively demonstrate whether any observed effect is caused by
success, failure, or both success and failure. Addressing this question requires
a different approach. I used propensity-score matching to parse the effects of
successful and unsuccessful leadership targeting. Matching is the preferred approach
because it can ensure balance on observed covariates. Given that
matching cannot ensure balance on unobserved covariates, however, these results
are admittedly more speculative than those presented in the next section.
Results
This section presents the main results of my analysis. I begin by using OLS regressions
with robust standard errors adjusted for clustering at the campaign
level.40
All regressions include ªxed effects for the number of attempts that occurred
in a campaign-year and for the decade during which each attempt
occurred. I also include ªxed-effects speciªcations for the type of attempt (i.e.,
the method used to target the insurgent leader) and the region in which attempts
occurred. These speciªcations are labeled in each table.
termination
Table 3 displays estimates of leadership decapitation’s effect on campaign outcomes.
The ªrst three columns estimate the effect of decapitation on war termination.
The dependent variable is campaign termination; it is a dummy coded
“1” if the campaign ended in the year in which a decapitation strike took place.
The ªrst column presents the results without additional ªxed effects; the second
column includes ªxed effects for attempt type; the third column includes
ªxed effects for region; and the fourth column includes ªxed effects for both
attempt type and region. In each regression, campaign termination was regressed
on decapitation attempts’ success or failure; the results are estimates of
the average effect of successful decapitation strikes compared with failed
attempts.
The results displayed in table 3 suggest that campaigns are more likely to
end after leadership decapitation. The estimate shown in column 1 suggests
International Security 36:4 62
40. On using OLS to analyze limited-dependent variables such as those examined below, see
Joshua D. Angrist, “Estimation of Limited-Dependent Variable Models with Dummy Endogenous
Regressors: Simple Strategies for Empirical Practice,” Journal of Business and Economic Statistics,
Vol. 19, No. 1 (January 2001), pp. 2–16. Probit regressions (not reported), however, produce similar
results.
that leadership decapitation increases the probability of war termination by
27 percentage points and is signiªcant at the 1 percent level. This result is robust:
the estimates displayed in columns 2 and 3 range from 0.26 to 0.29, and
all of the speciªcations are signiªcant at the 1 percent level. In each speciªcation,
the lower bound of the 95 percent conªdence interval of the estimate is
above “0.” These results change little when attempt type or region ªxed effects
are included. They are also robust to nonparametric modeling; in each of the
nonparametric speciªcations, the results are signiªcant at the 1 percent level.
victory
Columns 4–6 of table 3 estimate the effect of decapitation on government victory.
The dependent variable is a dummy coded “1” if the government defeated
its opponent in the year that the decapitation strike occurred. As in the
termination analysis, the independent variable is attempt success or failure,
which is a dummy coded “1” if an attempt succeeded at capturing or killing its
target.
The results suggest that governments are more likely to win when they
successfully target militant leaders. The coefªcient in column 4 shows that incumbents
were an estimated 32 percentage points more likely to defeat insurgencies
in years where counterinsurgents removed militant leaders than in
years where such attempts failed—a sizable advantage. This estimate is statistically
signiªcant at the 1 percent level. Like the results reported in the campaign
termination analysis, the effect of decapitation victory is robust. In each
Does Decapitation Work? 63
Table 3. Leadership Decapitation and Campaign Outcomes
Dependent Variable: Termination Dependent Variable: Victory
(1) (2) (3) (4) (5) (6)
Success 0.273*** 0.290*** 0.260*** 0.321*** 0.338*** 0.310***
(0.079) (0.081) (0.091) (0.073) (0.075) (0.084)
Constant Ϫ0.140** Ϫ0.319** Ϫ0.427** Ϫ0.173** Ϫ0.416*** Ϫ0.505***
(0.068) (0.126) (0.179) (0.075) (0.129) (0.171)
Type
(ªxed
effect)
no yes yes no yes yes
Region
(ªxed
effect)
no no yes no no yes
N 103 103 103 103 103 103
Robust standard errors appear in parentheses. ***p Ͻ 0.01, **p Ͻ 0.05, *p Ͻ 0.10.
speciªcation, decapitation is signiªcant at the 1 percent level; the lower-bound
estimate of the 95 percent conªdence interval is above zero; and various combinations
of ªxed effects do not change the effect.
In sum, the evidence strongly suggests that leadership decapitation has
substantial causal effects on campaign outcomes—removing militant leaders
increases counterinsurgents’ chances of achieving quick, successful campaign
terminations.
lethality
Table 4 displays the estimated causal effect of leadership decapitation on the
intensity of violence in counterinsurgency. Consistent with the evidence that
leadership decapitation increases the likelihood of war termination and counterinsurgent
victory, the evidence also suggests that leadership decapitation
reduces conºict violence. Columns 1 and 2 in table 4 show the results of negative
binomial regressions in which the dependent variable is the number of
people killed by an insurgency in a given campaign-year. As expected, the sign
of the point estimate in column 1 is negative, but it is not statistically signiªcant.
The speciªcation in column 2 estimates the same negative binomial
model, but it adds region and attempt type ªxed effects. This regression is
signiªcant at the 1 percent level, and the point estimate is more than twice the
size of the coefªcient in column 1, suggesting that once differences that owe to
attempt type and region are accounted for, leadership decapitation is associated
with decreased violence.41
The result in column 3 provides additional
conªrmatory evidence. It presents the same negative binomial regressions as
columns 1 and 2 but includes a lag of the dependent variable on the right-hand
side of the equation. Accounting for the number of people killed by insurgencies
at time t Ϫ 1 helps control for any unobserved cross-sectional differences
in insurgent violence. The estimated effect of decapitation is again negative
and signiªcant at the 1 percent level.
attacks
Next, I examined the impact of leadership decapitation on the rate of insurgent
attacks. It is useful to examine attacks separately from lethality because
International Security 36:4 64
41. As before, all regressions include ªxed effects for the decade in which each decapitation attempt
occurred and for the number of attempts that were carried out during each campaign-year
with at least one attempt. This ensures that any violence-reducing effect observed in the regression
results cannot be attributed to unusually aggressive targeting operations or temporal trends. For
example, during the Cold War, there was less stigma attached to targeted killing programs that
aimed to eliminate enemy leaders in covert operations, a trend which was at least temporarily reversed
during the 1990s.
whereas violence usually captures the quality of militant operations—that is,
the extent to which the insurgency is able to inºict losses on its targets—attack
frequency captures the pace of militant activities. Militants using a guerrilla
warfare strategy might conduct many small attacks, with lower levels of
lethality, in order to harass and intimidate its adversaries, whereas other militant
organizations may conduct “spectacular” but infrequent attacks.42
I use a similar approach to estimate the effect of decapitation on insurgent
attacks. The baseline speciªcations are negative binomial regressions, speciªed
in table 4 both without (column 4) and with (column 5) ªxed effects. A lagged
dependent variable speciªcation is shown in column 6. The results suggest
that, on average, decapitation is associated with fewer insurgent attacks. The
results of the ªxed-effects speciªcations in columns 5 and 6, for example, are
negative and statistically signiªcant at the 5 and 1 percent levels, respectively.
The coefªcient shown in column 4 is also negative, but it is small and insigniªcant.
As with the violence analysis, this suggests that, after including basic
controls, decapitation is associated with fewer insurgent attacks.
Does Decapitation Work? 65
42. Indeed, scholars have also suggested that decapitation has different effects on levels of militant
lethality than it does on rates of militant attacks. For example, Byman observed that Israel’s
targeted killing program reduced the lethality of Hamas attacks but increased the total number of
attacks. Byman, “Do Targeted Killings Work?” p. 103.
Table 4. Leadership Decapitation and Violence
Dependent Variable: Conºict Intensity Dependent Variable: Attacks
(1) (2) (3) (4) (5) (6)
Success Ϫ0.774 Ϫ1.994*** Ϫ1.637*** 0.212 Ϫ0.728** Ϫ1.685***
(0.494) (0.426) (0.420) (0.480) (0.328) (0.444)
Constant Ϫ1.677* Ϫ1.640* Ϫ1.308 Ϫ0.925* Ϫ1.420* Ϫ1.392*
(0.890) (0.868) (0.950) (0.552) (0.860) (0.811)
Type
(ªxed
effect)
no yes yes no yes yes
Region
(ªxed
effect)
no yes yes no yes yes
Lagged
dependent
variable
no no yes no no yes
N 102 102 90 102 102 90
Robust standard errors appear in parentheses. ***p Ͻ 0.01, **p Ͻ 0.05, *p Ͻ 0.10.
success and failure
Targeting insurgent leaders is a game of chance. More bids to capture or kill
insurgent leaders fail than succeed. But what are the consequences of failure?
The element of chance in leadership targeting enables causal identiªcation.
The evidence presented above suggests that these outcomes—successful
versus failed decapitation strikes—have a signiªcant impact on the dynamics
and outcomes of counterinsurgency campaigns. Although it is tempting to attribute
the causal effects identiªed above to successful leadership targeting,
doing so would be premature. Because my identiªcation strategy does not include
an untreated control group—it instead uses exogenous variation in successful
and failed attempts—the possibility that failed attempts are driving the
observed relationships cannot be ruled out. Speciªcally, negative externalities
of failed decapitation strikes could underlie the identiªed effects. That is,
when the tactics commonly used in decapitation strikes, such as bombings and
raids, fail to eliminate insurgent leaders but incite mass resentment, these failures
could decrease the chances of war termination and counterinsurgent victory
and increase the chances of escalated levels of insurgent violence.
To account for this potential issue, I assessed the impacts of both successful
and failed decapitation strikes on counterinsurgency outcomes. Identifying the
independent effects of success and failure alone is more difªcult than identifying
the difference between them because, while the evidence suggests that the
success of decapitation strikes is exogenous, conditional on an attempt taking
place, decapitation strikes themselves do not occur at random. Treating them
as if they do risks conºating the effects of successful and failed decapitation
strikes with change that would have occurred regardless. For example, if decapitation
strikes are more likely to occur when counterinsurgents believe that
insurgents are growing, or are going to grow, in strength and lethality, they
have an incentive to strike at the insurgency’s leadership from a position of relative
weakness. This dynamic appears to be motivating the United States’ escalation
of high-value targeting in Pakistan’s Federally Administered Tribal
Areas, for example. These strategic choices could lead analysts to erroneously
attribute any observed growth in militancy to high-value targeting attempts,
even though high-value targeting might have had no impact on the insurgency’s
capabilities or behavior.43
International Security 36:4 66
43. Alexander B. Downes makes an analogous argument about states’ decisions to use force
against civilians during desperate moments of interstate wars. See Downes, “Desperate Times,
Desperate Measures: The Causes of Civilian Victimization in War,” International Security, Vol. 30,
No. 4 (Spring 2006), pp. 152–195. For a general theory of leaders’ decisions to “gamble for resurrection”
in war, see H.E. Goemans, War and Punishment: The Causes of War Termination and the First
World War (Princeton, N.J.: Princeton University Press, 2000).
Propensity-score matching is the best tool available for addressing this challenge.
Propensity-score matching uses observable characteristics to predict decapitation
strikes and then uses this information to stratify the sample into
control and treatment groups that are balanced on observables.44
Stratifying
the sample in this way enables me to compare similar years with and without
decapitation strikes as if they were similar treatment and control groups.45
To implement this approach, for all countries i engaged in counterinsurgency
campaigns in all years t, I used the following equation:
P(ATTEMPTit) ϭ ⌽(Xit).
This estimator is used to predict attempts conditional on observables. Based on
the predicted probabilities estimated from this equation, I formed four blocks,
denoted by b, for varying levels of the propensity score and then checked the
balance on the treatment and control covariates in each block. Once the sample
was stratiªed and balanced, I estimated regressions using the following
equation:
Yib ϭ ␣b ϩ ␤1SUCCESSib ϩ ␤2FAILUREib ϩ ␥Xib ϩ εib,
where ␣b indicates ªxed effects for each propensity score block.46
Table 5 shows separate estimates of the effects of successful and failed decapitation
attempts on campaign termination and success. For each of these
dependent variables, three speciªcations are presented: column 1 presents an
OLS regression without controls, ªxed effects, or matching; the speciªcation in
Does Decapitation Work? 67
44. Daniel E. Ho, Kosuke Imai, Gary King, and Elizabeth A. Stuart, “Matching as Nonparametric
Preprocessing for Reducing Model Dependence in Parametric Causal Inference,” Political Analysis,
Vol. 15, No. 3 (January 2007), pp. 199–236; and Donald B. Rubin, Matched Sampling for Causal Effects
(New York: Cambridge University Press, 2006).
45. Compared with experimental and quasi-experimental approaches, the major weakness of
matching is that assignment to treated and control groups is based on observables. Without full
knowledge of the data-generating process, it remains possible that my estimates will be biased because
of selection on unobservables. Although selection bias is a potential concern when using any
matching estimator, matching remains a useful technique for scholars seeking to identify causal effects
because it ensures sample balance on observables and excludes extreme counterfactuals. See
Gary King and Langche Zeng, “The Dangers of Extreme Counterfactuals,” Political Analysis,
Vol. 14, No. 2 (November 2006), pp. 131–159.
46. Before estimating the effects of successful and failed decapitation strikes, I examined whether
pretreatment covariates in my dataset predicted observed decapitation attempts. Supplemental table
4 in the online appendix shows the results of probit regressions that included the same variables
used in the t-tests presented in table 2 above. The incumbent’s GDPPC is a signiªcant
predictor of decapitation attempts in two of six speciªcations. This is intuitive: wealthier governments
should be more likely to have the capability to aggressively target insurgent leaders. I control
for this variable in the regressions.
column 2 includes control variables and ªxed effects for attempt type and region;
and column 3 includes all of these regressors and uses matching to
ensure balance on covariates.
The results strongly suggest that successful leadership removals, not blowback
from failed attempts, drive the overall effect of leadership decapitation.
The results are displayed in table 5. For both successful and unsuccessful decapitation
attempts, the results are similar across the matched and unmatched
samples and are robust to the inclusion of ªxed effects and controls. Conªdence
in the ªndings is enhanced by the fact that the point estimates for
successful leadership removals shown in table 5 are consistent with those displayed
in table 3, which used exogenous variation in attempt outcomes to examine
whether the correlation between successful attempts and campaign
termination and government victory differed from the correlations between
failed attempts and those outcomes. Speciªcally, the estimated effect of successful
decapitation attempts remains similar in size to the estimates shown in
table 3. The coefªcients presented in table 5 suggest that leadership decapitation
is associated with a 28-percentage point increase in the probability of
termination during the year in which the decapitation attempt occurred and a
29- or 30-percentage point increase in the probability of government victory.
Both of these results are signiªcant at the 1 percent level.
There is little evidence of a “blowback effect.” As the blowback hypothesis
would predict, the point estimates for failed attempts are negative, which indicates
that failed attempts to capture or kill insurgent leaders may have counterproductive
effects on governments’ chances of defeating insurgencies.
International Security 36:4 68
Table 5. The Impact of Successful versus Failed Attempts
Dependent Variable: Conºict Intensity Dependent Variable: Attacks
(1) (2) (3) (4) (5) (6)
Success 0.282*** 0.284*** 0.284*** 0.296*** 0.289*** 0.288***
(0.072) (0.073) (0.074) (0.069) (0.070) (0.070)
Failure Ϫ0.010*** Ϫ0.022 Ϫ0.030 Ϫ0.016 Ϫ0.022 Ϫ0.021
(0.037) (0.037) (0.033) (0.027) (0.028) (0.028)
Constant 0.039 0.155 0.028 0.020 0.012 Ϫ0.220
(0.032) (0.112) (0.250) (0.027) (0.070) (0.193)
Controls no yes yes no yes yes
Matching no no yes no no yes
N 932 932 932 932 932 932
Robust standard errors appear in parentheses. ***p Ͻ 0.01, **p Ͻ 0.05, *p Ͻ 0.10.
There is not enough evidence, however, to reject the null hypothesis—that
failed decapitation operations have no overall impact on states’ chances of
strategic success. Indeed, the estimated effect of failed attempts is small and
far from statistically signiªcant, with p-values that range from 0.356 to 0.788.
Taken together, this evidence strongly indicates that the successful removal of
insurgent leaders, not blowback from failed attempts, underlies my key ªndings
on the effects of leadership decapitation in counterinsurgency operations.
Results II: When Is Decapitation Effective?
The results presented above strongly suggest that decapitating insurgencies
has causal effects on counterinsurgency campaign termination, outcomes, levels
of conºict intensity, and insurgent attack rates. Another key question is
whether leadership decapitation is more or less effective against some types of
insurgencies than others. I examine this question below.
ideological and identity-based insurgencies
A central debate in the civil war literature concerns whether the dynamics of
“ideological” and “identity” conºicts differ.47
Communist insurgencies are
usually categorized as ideological movements; ethnic and religious groups
are usually classiªed as identity-based movements. Scholars suggest that a key
distinction between ideological and identity-based conºicts is that ideological
conºicts are fought over how polities should be governed, whereas identity
conºicts usually involve at least one party that views itself as fundamentally
different from the other and, consequently, is ªghting to pursue some
form of self-determination. This argument implies that fundamental differences
between belligerent parties characterize identity conºicts, making these
wars more difªcult to resolve.48
Ideology is more malleable, scholars argue,
and so ideological conºicts are easier to resolve.49
Does Decapitation Work? 69
47. Chaim Kaufmann, “Possible and Impossible Solutions to Ethnic Civil Wars,” International Security,
Vol. 20, No. 4 (Spring 1996), pp. 136–175; and Nicholas Sambanis, “Partition as a Solution to
Ethnic War: An Empirical Critique of the Theoretical Literature,” World Politics, Vol. 52, No. 4 (July
2000), pp. 437–483.
48. Monica Duffy Toft, The Geography of Ethnic Violence: Identity, Interests, and the Indivisibility of Territory
(Princeton, N.J.: Princeton University Press, 2003); Stacie E. Goddard, “Uncommon Ground:
Indivisible Territory and the Politics of Legitimacy,” International Organization, Vol. 60, No. 1 (Winter
2006), pp. 35–68; Ron E. Hassner, “The Path to Intractability: Time and the Entrenchment of Territorial
Disputes,” International Security, Vol. 31, No. 3 (2006/07), pp. 107–138; and Monica Duffy
Toft, “Getting Religion? The Puzzling Case of Islam and Civil War,” International Security, Vol. 31,
No. 4 (Spring 2007), pp. 97–131.
49. On the challenges of resolving ethnic conflicts via negotiated settlement, see Alexander B.
Downes, “The Problem with Negotiated Settlements to Ethnic Civil Wars,” Security Studies, Vol. 13,
To the extent that this argument is true, an observable implication is that
ideological insurgencies should be more likely to collapse after a leadership
decapitation incident because these groups should, on average, have less resolve
against a demonstrably threatening government or third-party counterinsurgent
than groups engaged in identity-based conºicts.
Yet scholars have made the opposite claim: they argue that insurgencies
with a communist ideology tend to be particularly durable because of their
mass-based ideology and political organizations, which are typically inºuenced
by Soviet political organization.50
The implication of this argument is
that communist insurgencies’ durability should make them more resilient to
the loss of key individual leaders than other types of insurgencies.
I examine these competing hypotheses empirically in tables 6 and 7; the results
support neither argument. The results are from OLS regressions in which
counterinsurgency victory is regressed on the outcome of decapitation attempts
against communist insurgent leaders.51
The main effect of successful
International Security 36:4 70
No. 4 (Summer 2004), pp. 230–279; and on religion, see Toft, “Getting Religion?”; and Ron E.
Hassner, War on Sacred Grounds (Ithaca, N.Y.: Cornell University Press, 2009).
50. Lucian Pye, Guerrilla Communism in Malaya (Princeton, N.J.: Princeton University Press,
1956); and Weinstein, Inside Rebellion, pp. 20–31.
51. Because these are saturated regression models, or regressions with discrete explanatory variables
where the model includes a separate parameter for all possible values taken by the explanatory
variables, the conditional expectation function is fit correctly regardless of the distribution of
Yi. Linear models can thus be used to estimate the effects of the regressors. OLS regression has numerous
advantages over nonlinear models in this situation, because nonlinear models require the
researcher to make numerous decisions (e.g., the weighting scheme and derivatives vs. finite difTable
6. Leadership Decapitation and Ideological Insurgencies
Dependent variable: Victory (1) (2) (3) (4)
Success 0.361*** 0.367*** 0.327*** 0.333***
(0.086) (0.083) (0.094) (0.093)
Ideological 0.140 0.139 0.095 0.064
(0.102) (0.106) (0.084) (0.100)
Success*Ideological 0.143 0.124 Ϫ0.109 Ϫ0.086
(0.183) (0.176) (0.178) (0.180)
Constant Ϫ0.222*** Ϫ0.433*** Ϫ0.312** Ϫ0.472**
(0.075) (0.144) (0.138) (0.202)
Type (ªxed effects) no yes no yes
Region (ªxed effects) no no yes yes
Observations 102 102 102 102
Robust standard errors appear in parentheses. ***p Ͻ 0.01, **p Ͻ0 .05, *p Ͻ 0.10.
decapitation strikes is statistically signiªcant at the 1 percent level across the
speciªcations. The preferred speciªcation, which includes the full battery of
ªxed effects and is shown in column 4, yields a point estimate of 0.333, with
a standard error of 0.093. The point estimate for successful attempts, conditional
on the target being a communist leader, is negative across the regressions
shown in table 8, but it is not statistically signiªcant in any of the
speciªcations. It is therefore possible that the effect of leadership decapitation
on communist insurgencies is negative, but there is insufªcient evidence to
demonstrate this conclusively.
Similarly, the results for identity-based groups, which are given in table 8,
show that leadership decapitation’s main effect is positive, but the effect of decapitating
identity-based insurgencies, which I proxy using insurgencies with
secessionist aims, does not differ signiªcantly from that of other types of insurgencies.
No clear pattern can be discerned from the interaction term. The effect
of decapitating identity-based insurgencies appears to be small and the direction
of the relationship dependent on model speciªcation.
Thus it does not appear that the effect of removing the leaders of identityDoes
Decapitation Work? 71
ferences), whereas OLS is standardized and yields estimates that are consistent with the marginal
effects that must be computed from the estimates of nonlinear models in order to produce a causal
interpretation of these estimates. For more on this methodological choice, see Joshua D. Angrist,
“Estimation of Limited-Dependent Variable Models with Dummy Endogenous Regressors,” Journal
of Business & Economic Statistics, Vol. 19, No. 1 (January 2001), pp. 2–28; and Joshua D. Angrist
and Jörn-Steffan Pischke, Mostly Harmless Econometrics: An Empiricist’s Companion (Princeton, N.J.:
Princeton University Press, 2009), pp. 48–51, 102–107.
Table 7. Leadership Decapitation and Identity-Based Insurgencies
Dependent variable: Victory (1) (2) (3) (4)
Success 0.317*** 0.350*** 0.292*** 0.330***
(0.100) (0.105) (0.107) (0.114)
Identity 0.050 0.115* Ϫ0.032 0.098
(0.046) (0.066) (0.112) (0.114)
Success*Identity 0.021 Ϫ0.017 0.026 Ϫ0.014
(0.155) (0.145) (0.161) (0.153)
Constant Ϫ0.213*** Ϫ0.452*** Ϫ0.264 Ϫ0.560***
(0.073) (0.121) (0.166) (0.204)
Type (ªxed effects) no yes no yes
Region (ªxed effects) no no yes yes
Observations 102 102 102 102
Robust standard errors appear in parentheses. ***p Ͻ 0.01, **p Ͻ0 .05, *p Ͻ 0.10.
based insurgent groups differs from the effects of removing the leaders of
other types of insurgencies. And overall, the analysis reveals no evidence that
the distinction between ideologically and identity-based conºicts is salient in
terms of leadership decapitation’s effectiveness.
center-seeking insurgencies
Having examined the effect of decapitation on secessionist insurgencies, I now
turn to center-seeking insurgencies. Center-seeking insurgencies are those
guerrilla movements whose stated goal is to become the sovereign government
of the countries in which they ªght, regardless of their ideology or organization.
Although all civil wars are difªcult to resolve through negotiations,
conºicts in which insurgencies seek the center are particularly difªcult to mediate.
James Fearon and David Laitin show that conºicts with center-seeking
insurgencies are less likely to end in negotiated settlement than are secessionist
conºicts, possibly as a result of commitment problems.52
If the nature of insurgencies’
aims affects the parties’ ability to credibly commit to peace, one
might expect that decapitating center-seeking insurgencies would make it
even more difªcult for governments to credibly commit, reducing the chances
of a successful resolution. I test this proposition in table 8.
The results displayed in table 8 show that although the point estimates of
the interaction of Success*Center-Seeking are all in the expected negative diInternational
Security 36:4 72
Table 8. Leadership Decapitation and Center-Seeking Insurgencies
Dependent variable: Victory (1) (2) (3) (4)
Success 0.354*** 0.354*** 0.354*** 0.354***
(0.111) (0.111) (0.111) (0.111)
Center-Seeking Ϫ0.037 Ϫ0.037 Ϫ0.037 Ϫ0.037
(0.038) (0.038) (0.038) (0.038)
Success*Center-Seeking Ϫ0.069 Ϫ0.069 Ϫ0.069 Ϫ0.069
(0.144) (0.144) (0.144) (0.144)
Constant 0.037 0.037 0.037 0.037
(0.038) (0.038) (0.038) (0.038)
Type (ªxed effects) no yes no yes
Region (ªxed effects) no no yes yes
Observations 102 102 102 102
Robust standard errors appear in parentheses. ***p Ͻ 0.01, **p Ͻ0 .05, *p Ͻ 0.10.
52. Fearon and Laitin, “Civil War Termination.”
rection, they are small and statistically insigniªcant. Thus, although it remains
possible that decapitation is systematically less effective against center-seeking
insurgencies, there is little evidence to substantiate such a claim.
islamist insurgencies
Analysts have suggested that leadership decapitation is not an effective instrument
against Islamist insurgencies—perhaps because several recent highproªle
Islamist groups, such as al-Qaida in Iraq, have operated through
relatively ºat, cell-based organizations. This proposition is examined in table
9. The interaction between Success*Islamist shows a relatively small and
insigniªcant relationship between successful decapitation attempts against
Islamist insurgencies and counterinsurgency victory. Detecting a statistical effect
is unlikely, however, because the number of decapitations of Islamist insurgent
leaders in the data set is small (N ϭ 10). Yet the consistently positive
relationship between Success*Islamist and government victory suggests it is
possible that using decapitation strategies against Islamist groups is more effective
than previously believed. And, to the extent that Islamist groups organize
as ºat, cell-based networks, removing the leaders of such decentralized
organizations may be an effective means of exploiting organizational vulnerabilities.
Given that my dataset does not include Islamist insurgencies from the
post–September 11, 2001, period, however, caution should be used in extrapolating
from these ªndings.
Does Decapitation Work? 73
Table 9. Leadership Decapitation and Islamist Insurgencies
Dependent variable: Victory (1) (2) (3) (4)
Success 0.316*** 0.336*** 0.268*** 0.283***
(0.087) (0.088) (0.089) (0.091)
Islamist Ϫ0.027 Ϫ0.030 Ϫ0.008 Ϫ0.063
(0.039) (0.053) (0.118) (0.148)
Success*Islamist 0.063 0.043 0.154 0.134
(0.186) (0.170) (0.216) (0.203)
Constant Ϫ0.168** Ϫ0.357*** Ϫ0.284** Ϫ0.430**
(0.081) (0.123) (0.120) (0.167)
Type (ªxed effects) no yes no yes
Region (ªxed effects) no no yes yes
Observations 102 102 102 102
Robust standard errors appear in parentheses. ***p Ͻ 0.01, **p Ͻ0 .05, *p Ͻ 0.10.
organizational age
A key argument in Jordan’s article on the effectiveness of decapitating terrorist
organizations is that decapitation is particularly ineffective against older organizations.
She claims that older terrorist organizations are more resilient to decapitation,
both when compared with younger organizations that suffered
decapitation and with similarly aged organizations that never suffered decapi-
tation.53
I test this claim indirectly by examining the impact of leadership decapitation
during different time periods of counterinsurgency campaigns to
assess whether insurgencies that are strong enough to survive to ªght longer
campaigns are also more resilient to leadership decapitation. The results are
displayed in table 10.
Table 10 compares the outcomes that follow successful and failed decapitation
attempts in the ªrst ten years of counterinsurgency campaigns as well as
attempts that occur in campaigns lasting longer than ten years. Essentially, this
compares attempts in the upper quartile of attempts, by duration, with attempts
in the bottom three quartiles. The ten-year length is also a substantively
recognizable duration, now that the U.S. campaign in Afghanistan is in its
eleventh year, and key questions about the effects of U.S. high-value targeting
loom as the U.S. government searches for a way to wind down the war on acceptable
terms.54
International Security 36:4 74
53. Jordan, “When Heads Roll,” pp. 740–747. For more on this hypothesis, see Martha Crenshaw,
“How Terrorism Declines,” Terrorism and Political Violence, Vol. 3, No. 1 (March 1991), p. 79. Michael
C. Horowitz also uses organizational age to explain terrorist group activities. See Horowitz,
The Diffusion of Military Power: Causes and Consequences for International Politics (Princeton, N.J.:
Princeton University Press, 2010).
54. It should be reiterated that these results are not directly applicable for predicting the effect of
Table 10. Leadership Decapitation and Organizational Age
(1) (2) (3) (4)
Dependent variable: Victory 0–10 Year Campaigns 11ϩ Year Campaigns
Success (0.279*** (0.279*** (0.455** (0.455**
(0.083) (0.083) (0.156) (0.156)
Constant (0.0238 (0.0238 (0 (0
(0.024) (0.024) (0.001) (0.001)
Type (ªxed effects) no yes no yes
Region (ªxed effects) no yes no yes
Observations 75 75 27 27
Robust standard errors appear in parentheses. ***p Ͻ 0.01, **p Ͻ0 .05, *p Ͻ 0.10.
The point estimates of success are in the expected positive direction and are
statistically signiªcant at the 5 percent level or above, suggesting that governments
are more likely to defeat insurgencies after successful decapitations than
after failed attempts regardless of the campaign’s duration. Interestingly, these
results suggest that the impact of removing insurgent leaders might be even
larger in long campaigns than in shorter campaigns.55
This is consistent with
the hypothesis that leadership decapitation can help break the morale of insurgencies
that have been engaged in long, often difªcult, campaigns.
capture versus killing
Finally, I examine the relationships between the methods of targeting and war
outcomes. Several scholars have made a distinction between capture versus
killing, suggesting that capture should be more effective because it can lead to
intelligence gains through interrogation.56
To test this hypothesis, I categorized
targeting attempts either as “lethal” or “nonlethal” based on my coding of attempt
types. Bombings, combat, and shootings were all categorized as lethal
attempts; raids and sweep operations, which can be lethal but often are not intended
to be, were categorized as nonlethal unless they ultimately resulted in
the use of lethal force.57
Twenty-ªve nonlethal attempts are documented in the
data, as compared to ninety-four attempts categorized as lethal.
Contrary to this conventional wisdom, the results shown in table 11 suggest
that killing insurgent leaders is likely to be more effective than capturing them.
There is a statistically signiªcant relationship between operations that resulted
in the deaths of militant leaders and quicker war termination and government
victory. This result remains similar when I control for failed attempts and other
covariates, and it is robust to the matching estimator described above. OperaDoes
Decapitation Work? 75
successful high-value targeting in Afghanistan or Pakistan. Rather, they provide general information
on the average effect of leadership decapitation in counterinsurgency campaigns across a
large number of cases since the 1970s.
55. To be sure, although these findings are statistically significant, given the relatively small sample
of long wars (N = 27), the precision of the point estimates is likely to be reduced. The results
(not reported) are similar, however, when other duration cut points are used.
56. See Frankel, “The ABCs of HVT,” pp. 24–26; and Cronin, “How al-Qaida Ends,” p. 736. Jordan’s
research suggests that capturing “upper echelon” terrorists (as opposed to terrorist leaders)
might be more strongly associated with terrorist organization collapse than killing upper echelon
members, but that there is a stronger association between killing top leaders and organizational
collapse than between capturing them and organizational collapse. See Jordan, “When Heads
Roll,” p. 736.
57. In his June 2011 testimony to the Senate Armed Services Committee, for example, commander
of the Joint Special Operations (JSOC) Command, Vice Adm. William McRaven, disclosed that
JSOC commandos in Afghanistan had discharged their firearms in only about 15 percent of the
raids conducted in 2010. See Aamer Madhani, “Special Ops Nominee Defends Night Raids in
Afghan War,” National Journal, June 28, 2011, http://www.nationaljournal.com/nationalsecurity/
special-ops-nominee-defends-night-raids-in-afghan-war-20110628.
tions that resulted in the capture of militant leaders are also positively associated
with these outcomes, but these results are smaller and statistically
insigniªcant. These results are consistent with Jordan’s ªnding that killing top
leaders is more frequently associated with successful countermilitancy than arresting
them.58
More important, they not only suggest that killing militant
leaders represents a severe blow to militant organizational capacity and morale,
but they are consistent with arguments made by U.S. counterterrorism
strategists that high-value targeting operations themselves can yield tangible
information through sensitive site-exploitation techniques and other activities
that may lead to additional operations. These claims were substantiated by the
intelligence windfall that resulted from the Navy SEAL raid that killed Osama
bin Laden in May 2011.59
Conclusion
Targeting militant leaders is now a centerpiece of U.S. strategy in Afghanistan,
Pakistan, Somalia, and Yemen, but does capturing or killing militant leaders
International Security 36:4 76
58. Jordan, “When Heads Roll,” pp. 736.
59. On targeting and intelligence collection, see Michael T. Flynn, Rich Juergens, and Thomas
Cantrell, “Employing ISR: SOF Best Practices,” Joint Forces Quarterly, Vol. 50, No. 3 (Fall 2008),
pp. 57–61. On the intelligence collected during the bin Laden raid, see, for example, Andrew
Tilghman, “Bin Laden Raid Also Yields Trove of Intel,” Army Times, May 2, 2011, http://
www.armytimes.com/news/2011/05/military-bin-laden-raid-intelligence-materials-050211w/.
Table 11. Capture versus Killing
(1) (2) (3) (4)
Dependent variable Termination Termination Victory Victory
Kill 0.382*** 0.378*** 0.367*** 0.369***
(0.094) (0.094) (0.093) (0.093)
Capture 0.025 0.028 0.069 0.066
(0.095) (0.095) (0.094) (0.094)
Failure Ϫ0.004 Ϫ0.008 Ϫ0.004 Ϫ0.001
(0.037) (0.036) (0.028) (0.028)
Constant 0.097 0.234 Ϫ0.029 Ϫ0.115
(0.109) (0.172) (0.068) (0.124)
Controls yes yes yes yes
Matching no yes no yes
Observations 927 927 927 927
Robust standard errors appear in parentheses. ***p Ͻ 0.01, **p Ͻ0 .05, *p Ͻ 0.10.
work? Most extant research eschews the notion that removing enemy leaders
can help governments achieve military and political goals. Regardless of
whether a government’s adversary is a state, a terrorist organization, or a
guerrilla insurgency, the scholarly opinion has been that high-value targeting
is ineffective at best and counterproductive at worst.
The evidence presented in this article challenges this view. In previous studies,
causal inference and generalizability have been difªcult given research
design and measurement issues. I addressed these issues by employing a datadriven
approach in which I analyzed variation in the consequences of successful
and failed decapitation attempts in campaigns dating from the mid-1970s.
After correcting for the endogeneity and measurement issues that have hindered
previous studies, I found that neutralizing insurgent leaders has a substantively
large and statistically signiªcant effect on numerous metrics of
countermilitancy effectiveness. Speciªcally, the results showed that removing
insurgent leaders increases governments’ chances of defeating insurgencies,
reduces insurgent attacks, and diminishes overall levels of violence. Because
these effects were estimated by comparing the consequences of successful and
failed decapitation attempts, I conducted additional analysis to ensure that the
observed effects can be attributed to successful operations against insurgent
leaders rather than to blowback from botched high-value targeting missions.
This was conªrmed to be the case.
Yet the data also show conclusively that killing or capturing insurgent leaders
is usually not a silver bullet. Neutralizing insurgent leaders signiªcantly
increases governments’ chances of reducing violence, terminating wars, and
defeating insurgencies. A variety of different empirical tests consistently demonstrated
that governments were more likely to defeat insurgencies following
the successful removal of top insurgent leaders, but this probability was consistently
estimated at around 25 to 30 percent—a far cry from the silver bullet
many look for when they analyze leadership decapitation. Yet this effect indeed
provides a sizable advantage, which can help explain why governments
continue to invest in high-value targeting despite its legal ambiguity and normative
disrepute.
These are not the only ªndings with policy implications. Importantly, the results
do not support the common argument that the costs of failed targeting
outweigh the beneªts of successful targeting; although there is abundant evidence
that capturing or killing insurgent leaders is associated with key metrics
of successful counterinsurgency, there is no credible evidence of a martyrdom
effect, whereby trying but failing to neutralize militant leaders decreases governments’
chances of defeating insurgencies or increases levels of antigovernment
violence. The apparently low costs of failed targeting to operational
Does Decapitation Work? 77
effectiveness is consistent with choices made by states, such as Israel and the
United States, to continue to aggressively target individual members of insurgent
and terrorist organizations—including midlevel operatives who can
potentially lead them to senior leaders—despite the inherent uncertainty,
difªculty, and risks of doing so, and to continue to invest in intelligence capabilities
and Special Operations Forces dedicated to kinetic and nonkinetic
targeting. The role, responsibilities, and budget of the U.S. Special Operations
Command continue to expand even as signiªcant budget cuts become a reality
for the Department of Defense. As long as the United States continues to move
its ªght from the battleªeld to the shadows, this trend will likely remain true.
International Security 36:4 78
Appendix. Successful Leadership Decapitations
Government Insurgency Leader Year
Morocco Polisario El-Ouali Mustapha Sayed 1976
Indonesia Fretilin Nicolau Lobato 1978
Mozambique Renamo Andre Matsangaissa 1979
Nigeria Maitatsines Mohammadu Marwa 1980
India PLA N. Bisheswar Singh 1981
India PLA Thoundam Kunjabehari 1982
Colombia M-19 Carlos Toledo Plata 1984
Somalia SSDF Abdullahi Yusuf Ahmed 1984
India PREPAK R.K. Tulachandra 1985
Yemen YSP Abdul Fattah Ismail 1986
Pakistan MQM Altaf Hussain 1986
India KCF Manbir Singh Chaheru 1986
India KLF Aroor Singh 1988
India KLM Avtar Singh Brahma 1988
India KCF Labh Singh 1988
Sri Lanka JVP Rohana Wijeweera 1989
Pakistan MQM Altaf Hussain 1991
Peru Shining Path Abimael Guzmán 1992
Chad MDD Goukouni Guet 1992
Algeria GIA Mansouri Meliani 1992
India BKI Sukhdev Singh 1992
Indonesia Fretilin Xanana Gusmao 1992
India KLF Gurjant Singh Budhsinghwala 1992
Chad CNR Abbas Koty 1993
Algeria GIA Abdelhak Layada 1993
Indonesia Fretilin Antonio Gomes da Costa 1993
Algeria GIA Cherif Gousmi 1994
Algeria GIA Mourad Sid Ahmed 1994
India BTFK Gurbachan Singh Manochahal 1994
Russia Chechens Dzhokhar Dudayev 1996
Sierra Leone RUF Foday Sankoh 1997
Chad FDR Laokein Barde 1998
Philippines ASG Abdura jik Abubakar Janjalani 1998
Peru Shining Path Oscar Ramirez 1999
Angola FLEC-R Antonio Bento Bembe 1999
Turkey PKK Abdullah Ocalan 1999
Sierra Leone RUF Foday Sankoh 2000
India UNLF Samarendra Singh 2001
Chad MDJT Youssouf Togoimi 2002
Angola UNITA Jonas Savimbi 2002
Algeria GIA Antar Zouabri 2002
Algeria GSPC Nabil Sahraoui 2004
Russia Chechen Aslan Maskhadov 2005
United States/Iraq AQI Abu Musab al-Zarqawi 2006
Philippines ASG Khadaffy Janjalani 2006
Sri Lanka LTTE Velupillai Prabhakaran 2009
Does Decapitation Work? 79