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By J.G. Seabrook

Decapitating a terrorist group by removing its leader is an effective tactic. Whether a leader is killed or captured, the group must deal with re-establishing leadership, smoothly transition from one leader’s vision to another’s, minimise any disagreements over new leadership, review how the leadership loss happened, and then recommence operations. Tactically, it is effective. However, decapitation’s effectiveness at an operational level across a conflict zone and strategically into the subsequent generations cannot so clearly be judged. Removing a strong leader can make way for another to consolidate a greater threat. The loss of an inspiring leader is often referenced as the fuel to recruit more willing terrorists. Also, removing a terrorist leader resets counter-terrorism organisations’ own intelligence-gathering and operations planning – though terrorists should not be protected through counter-terrorists’ unwillingness to start again.

This essay will argue decapitation is an effective counter-terrorism tactic, but that like all tactics it should be executed as part of an intelligence-driven, operationally layered strategy. Wanton killing should be avoided, however, the removal of a personality unlikely to allow an eventual negotiated peace is a legitimate toll for conflict resolution. First this essay will define decapitation, and examine how academic texts describe killing or capturing terrorist leaders. Then it will look to broaden the definition to consider forms of temporary decapitation other than capture, specifically neutralising a terrorist leader’s power through other means. This will look at how sustained pursuit of a terrorist leader can absorb so much time and effort they can no longer functionally lead. Then the essay will examine killing, capture, and neutralisation using effective and ineffective examples of each to compare the conditions that make decapitation an effective overall counter-terrorism tactic.

Most texts focus on defining decapitation in the broader context of a terrorist group’s viability afterwards. Broader studies of terrorist groups create this lens rightly, though doing so also colours assessments of decapitation’s effectiveness as a counter-terrorism tactic. If we judge decapitation’s effectiveness only compared to that group’s dissolution, then we ignore the nuances that time gained, capability degraded, and inadequate subsequent leadership might offer to counter-terrorism stakeholders at all levels. Osama bin Laden’s killing for example resulted in the less inspiring Ayman al-Zawahiri’s succession and a relatively unimpressive track record for al-Qaeda’s subsequent operational effectiveness. As such, in defining both decapitation and its effectiveness, this essay will argue decapitation must be judged across strategic, operational, and tactical contexts. 

Audrey Kurth Cronin, the authority on ending terrorism, defines decapitation as the removal by arrest or assassination of strategic and operational leaders[1]. This definition will lead most academic analysis to define decapitation in terms of killing and capture. However, this essay will consider decapitation in more mechanical terms to better judge effectiveness. This allows analysis of temporary and permanent removal of strategic and operational leaders, and as such how both temporary and permanent decapitation might shape a terrorist group’s activities. This becomes especially important when considering how counter-terrorism policy and planning may benefit from temporarily removing leaders to undermine a group’s tactical effectiveness during a key milestone in the group’s planning. For example, the capture of a tactical or operational commander in the Islamic State’s Afghanistan branch (ISIS-Khorasan) prior to Ramadan or Afghanistan’s fighting season could reduce violence in that leader’s area of operations precisely as it attempts annual increases in tempo. Losing a charismatic mastermind will surely have a more damaging effect on a group if it comes at the precise moment the leader is most needed.

Furthermore, by defining decapitation as temporary or permanent removal of leaders, we can analyse the effectiveness of the operation in non-immediate terms. The capture of some operational leaders will no doubt yield opportunities in future counter-terrorism operations not always immediately obvious to planners. In judicial systems in Iraq and Afghanistan, for example, terrorist leaders can be eventually released either following their sentence or after some form of corruption. 

Extremists commonly return to their terrorist group or another, as the Islamic State group’s leaders did. Self-proclaimed caliphs Abu Bakr al-Baghdadi and now Amir Mohammed Abdul Rahman al-Mawli al-Salbi returned to Tanzim Qa’idat al-Jihad fi Bilad al-Rafidayn[2] – the group that evolved into the Islamic State of Iraq and then the Islamic State of Iraq and the Levant (ISIL). Their time in custody will have included interrogation for intelligence and law enforcement purposes. Journalist Martin Chulov cites al-Mawli’s 2004 detention in the United States Military’s Camp Bucca[3] as one source of the Western intelligence services’ scant information on the current ISIL caliph. Al-Mawli’s ethnic origin as a Turkman and the degree of collaboration with American interrogators will surely offer opportunities to undermine the legitimacy and piety of the Salafist, self-proclaimed ruler of all Muslim Arabs. As such, al-Mawli’s temporary capture will no doubt enable efforts to end his leadership of the ISIL.

Furthermore, by defining decapitation in terms of temporary or permanent removal of a leader, we can also analyse the effectiveness of removing leaders from the operational environment by eliminating their ability to participate. In this case, a leader’s removal is not necessarily into a counter-terrorism organisation’s control. When counter-terrorism operations focus enough time and effort on a terrorist leader, that pressure can effectively neutralise the leader. Keith Cozine argued in his analysis of Osama bin Laden’s killing, that the intensity of the American intelligence community’s efforts to find bin Laden meant his only real objective was to stay alive and symbolically lead al-Qaeda[4]. Until his killing, bin Laden was effectively neutralised, devolving his leadership responsibilities to others, while not being able to empower those delegates with as much authority as his death did, when they all moved up the leadership ladder. Determining options for ending terrorism with the use of decapitation should consider this strategic neutralising effect, especially when we consider the reality Audrey Kurth Cronin presents, “ISIS is not al-Qaeda.  It’s not an outgrowth or part of the older radical Islamist organisation…ISIS is its successor.”[5] Did bin Laden’s death set the conditions for another terrorist organisation to aspire to the role as leading radical Islamist threat?

Killing a terrorist leader is the quintessential decapitation tactic. Groups without the leaders, who built them into serious threats, are judged more likely to weaken or fall apart. In terrorist groups built as personality cults without leadership redundancy and corporate resiliency, the permanent removal of a leader seems more likely to end the terrorist threat. Small groups will more likely be vulnerable to lethal decapitation. Within the broader Hezbollah movement, Lebanon’s small Islamic Jihad Organisation (IJO) relied on its founder and inspiring mastermind Imad Mughniyeh for most of its operational successes. When they merged, Hezbollah benefitted from the motivated Mughniyeh’s drive. In describing Israel’s history of targetted killings, Ronen Bergman noted how Mughniyeh was the fundamental driving force behind Hezbollah and IJO’s overseas attacks[6]. As a result, Israel’s Cabinet found it easy to justify his killing. Bergman argues the distinct link between Hezbollah’s slowed overseas operations and the timing of Mughniyeh’s death. Shi’a firebrands have, however, used Mughniyeh’s death to motivate more support for their cause. Hassan Nasrallah declared Hezbollah’s open warfare with Israel at Mughniyeh’s funeral[7]. Ten years later, the late Major General Qassem Suleimani[8], Iran’s former expeditionary operations commander, used Mughniyeh’s death to justify Iran’s military adventurism.

Resilient, well-designed leadership architectures in terrorist groups can reduce the targeted killing’s effectiveness. Groups with less personalised names like ‘the foundation’ (al-Qaeda) or ‘the state’ (al-Dawah – ISIL) seem likely to present assassination planners with more risks and trade-offs based on their inherent leadership redundancy. These include the likelihood of a more dangerous leader emerging from lower in the network or the martyrdom of one leader inspiring more recruits. Michael Kirk-Smith and James Dingley note how terrorism often thrive on its martyrs and the mass communal and highly emotive funerals that follow. These often become platforms for recruiting and reinvigorate a cause[9].

Cronin argues ISIL has evolved into more a state sponsor of terrorism than a simple terrorist organisation[10]. With the loss of any territory in Iraq or Syria, the group’s new ‘external operations’ reality seems likely to present a greater threat to the West than when their atrocities were contained in Iraq and Syria. ISIL leader Abu Bakr al-Baghdadi’s October 2019 killing came after the group’s territory was lost and the “pseudo-state led by a conventional army”[11] was mostly destroyed. Al-Baghdadi’s death at his own hand was not as effective as an earlier assassination would have been. While the Defeat-ISIL Coalition will likely have attempted to use Baghdadi’s death as a metaphor for ISIL’s own pitiful position, in reality his death was not very effective in undermining the group’s contemporary operations. In fact, the change in leadership as the Islamic State group committed to decentralised global operations seems more likely to have created a greater problem for intelligence communities and militaries to assess and counter. While al-Baghdadi killed himself, the capture mission sent to fetch him seems unlikely to have had any other result. As such, this essay assessed that decapitation as a killing, despite being a suicide. 

More academics than not seem to agree the most effective decapitation tactic is capture[12]. It has the lowest ethical concerns and matches democratic preferences best. Several examples also show the easy correlation between arrests decapitating a movement and its decline. Cronin cites Japan’s Aum Shinrikyo, whose leaders were incarcerated after a sarin gas attack, precipitating the group’s decline from 40,000 supporters in 1995 to approximately 1,650 fifteen years later[13]. Cronin highlights at a more academic level how capture reiterates the rule of law, applying law enforcement and judicial solutions to problems[14]. This, in turn, robs terrorist leaders of any glamour, putting them on the same standing as any other criminal being processed through a faceless bureaucracy. Put more simply, Cronin points out, “there is nothing glamourous about languishing in jail.”[15] While the judicial process robs terrorists of any sense of legitimacy, capture offers counter-terrorism policy-makers and planners more options in dismantling the broader organisation.

By imprisoning a terrorist leader, a state then controls the narrative around them, while simultaneously placing the organisation in huge difficulty. Does a terrorist group simply replace their leader once captured? If so, would that not undermine the legitimacy of the captured leader’s tenure and operations? A newly installed leader would more likely remain in their predecessor’s shadow, or worst be beholden to snippets of direction from an isolated detainee. With a terrorist leader still alive, a new leader often struggles to capitalise on the full authority of the leadership role. Turkey presents an excellent example of how to use a leader’s capture to best effect with the detainment of Abdullah Öcalan, the leader of the Partiya Karkaren Kurdistan (PKK). Despite recent Turkish claims the PKK remains an overwhelming existential threat, in reality Öcalan’s imprisonment crippled the PKK. The Washington Post reported security analysts’ opinion in 1999 that Öcalan’s capture at the tail end of a Turkish military campaign to forcibly root out PKK sympathisers was effectively the end of the PKK after operations resulting in 37,000 casualties[16].

Control over Öcalan has slowly given Turkey considerable ability to reduce Kurdish terrorism to remnants of its once massive fighting force. This began in 1999 when photographs of a drugged, groggily slumped-over, and disoriented Öcalan were broadcast internationally piercing the personal reputation Öcalan had groomed to endear him as a romanticised freedom fighter across the Kurdish diaspora. This media effort steadily continued and resulted in Öcalan reversing his position twenty years after imprisonment, claiming he no longer sought Kurdish independence, and wanted to find a solution to Kurdish identity within the Turkish state[17]. Twenty years may seem like a long counter-terrorism campaign, but when attempting to ensure generational change, this investment in undermining terrorism’s underlying causes is necessary.

In analysing the end of Basque terrorism, Joseba Zulaika and Imanol Murua describe the beginning of Euskadi ta Askatasuna’s (ETA’s) downfall as the result of the strategic neutralisation of both ETA and their political masters in Batasuna[18]. After decades of violence and peace negotiations, the Spanish Government effectively left Batasuna with no options but to end the armed resistance. The Basque independence movement had been neutralised through arrests and harassing Police operations[19]. The movement’s neutralisation seems more coincidentally the sum of official efforts to counter the organisation’s military arm. It does demonstrate, however, how layered strategy and operations can multiply the effectiveness of other counter-terrorism efforts. Zulaika and Murua argue the Spanish Government’s tactics mounted to harassment – but given the higher ethical quandaries associated with killing[20], this seems a low bar to clear in countering terrorism[21]. Arresting key terrorist leaders deters a group’s supporters or sympathisers from getting caught providing support. Arresting associates of terrorist leaders and their more legitimate political masters deters supporters from being associated at all. The Basque case shows how neutralising key leaders and capturing the most effective terrorist commanders can isolate a group from its base, and eventually starve it of any legitimacy.

With any decapitation effort, intelligence must drive operations and policy. Not only in the tactical effort to find a terrorist, but in the operational analysis of when and which decapitation method would be most effective. Ideally, tactical level intelligence will pre-empt and stop attacks. Kirk-Smith and Dingley noted a key lesson from practitioners’ reflections on intelligence gathering during Northern Ireland’s Troubles was, “the ability to pre-empt terrorist acts and so make their entire existence, effort, and self-sacrifice seem pointless and a waste of time and resources[22].” Stopping enough attacks and publicising a group’s impotence can likewise have a neutralising effect. Why follow leaders who cannot actually perpetrate anything of note? With enough intelligence resources, providing effective counter-terrorism security can isolate leaders from their support base. With the right information operations and public relations, terrorist leaders can be decapitated by influence activities that cut them off from legitimacy and competence. 

Separately, an interesting example of decapitation with layered operational effects is shown when the Abu Sayyaf Group’s leader Hatib Hajan Sawadjaan was killed in April 2020 in the southern Philippines[23]. Though a seemingly simple decapitation, its operational effectiveness was amplified as the group struggled to decide whether to find a new leader. For some months following the Sawadjaan’s reported killing, Abu Sayyaf argued over whether or not he was dead. As a result, the effective neutralisation of the group’s leadership was dragged out as the group could not begin the process of finding a new leader. Cronin describes how Abu Sayyaf’s succession is littered with leaders being killed or captured[24]. After the killing of the group’s founder Abdurajak Abubakar Janjalani, Abu Sayyaf reoriented away from fanaticism onto a more malleable criminal modus operandi. With this year’s confusion over Sawadjaan’s death, the Armed Forces of the Philippines (AFP) not only neutralised Abu Sayyaf but also (probably by accident) delayed the reconstitution of effective leadership. In this case, the AFP arguably used a kinetic operation to have an information-operations effect, resulting in more time to evaluate Abu Sayyaf’s next moves and to plan how to neutralise them. This was especially important in Abu Sayyaf’s case where history showed Janjalani’s death resulted in three splintered groups going in different directions[25].

This essay set out to prove how decapitation could be an effective tactic. Like any action, it is only effective when well suited to the situation and layered with other tactics and planning. Small terrorist groups reliant on a charismatic leader or built as a personality cult are the most vulnerable to decapitation whether an assassination or capture. Both can undermine a group’s ability to function. Meanwhile capturing enemies provides greater opportunities to degrade a terrorist group. Öcalan’s case proves how to most effectively exploit a decapitation with information operations to influence supporters and sympathisers. Efforts to humiliate a terrorist leader are an effective way to undermine the imprisoned leader’s legitimacy and control. This essay broadened the definition of decapitation to be the temporary or permanent removal of leaders, owing to the opportunities presented by those temporary removals through capture or neutralisation in longer campaigns. Decapitation is an effective counter-terrorism tactic, but it needs to be one effort woven into broader strategic, operational, and tactical undertakings to counter terrorism. If it is not layered into a holistic counterterrorism policy or strategy, then it can too easily create greater problems than it solves.


1.  Audrey Kurth Cronin, How Terrorism Ends: Understanding the Decline and Demise of Terrorist Campaigns, (Princeton and Oxford: Princeton University Press, 2009), 27.

2. Jeffrey Poole, “Zarqawi’s Pledge of Allegiance to al-Qaeda: From Mu’Asker al-Battar, Issue 21” Terror Monitor, Vol. 2 No. 24, Jamestown Foundation, 16 December 2004.

3. Martin Chulov and Mohammed Rasool, “Isis founding member confirmed by spies as group’s new leader,” The Guardian, 20 January 2020, available at, (accessed 15 August 2020).

4.  Keith Cozine, “Teaching the Intelligence Process: The Killing of Bin Laden as a Case Study,” Journal of Strategic Security, Vol .6, No. 5 (also in Vol. 6, No. 3) 2013, 80-87.

5.  Audrey Kurth Cronin, “ISIS is not a Terrorist Group,” Foreign Affairs, Vol. 94, No. 2, March-April 2015.

6. Ronen Bergman, Rise and Kill First: The Secret History of Israel’s Targeted Assassinations, (New York: Penguin Random House, 2018). 

7. Anti-Defamation League, “Hezbollah Threatens “Open War” on Israel,” 31 March 2008, available at (accessed 29 August 2020).

8. Fars New Agency, “The revenge for Imad Mughniyeh’s blood is the destruction of the Zionist Regime,” Farsi News, 15 February 2018. available at (accessed 27 August 2020).

9. Michael Kirk-Smith and James Dingley, “Countering terrorism in Northern Ireland: the role of intelligence,” Small Wars Journal¸ Vol. 20, Nos. 3-4, September – December 2009, 557.

10.  Audrey Kurth Cronin, “ISIS Is More Than A Terrorist Group,” Foreign Affairs, 23 March 2016, available at, (accessed 26 August 2020.).

11. Cronin, “ISIS is not a Terrorist Group.” 

12. Stewart J. D’Alessio, Lisa Stolzeberg, & Dustin Dariano, “Does Targeted Capture Reduce Terrorism?” Studies in Conflict and Terrorism, Vol. 37, 2014, 882.

13.  Cronin, How Terrorism Ends, 24.

14. Cronin, How Terrorism Ends, 17.

15.  Ibid.

16.  Amberin Zaman, “Öcalan conducted ruthless offensive,” The Washington Post, February 1999, available at (accessed 29 August 2020.).

17.  Al Jazeera, “Jailed PKK leader Öcalan ‘ready for a solution’ with Turkey,” Al Jazeera News, 09 August 2019, available at*003125441.html (accessed 24 August 2020).

18. Joseba Zulaika & Imanol Murua, (2017) “How terrorism ends – and does not end: the Basque case,” Critical Studies on Terrorism, Vol. 10, No. 2, 201, 340.

19. Zulaika & Murua, (2017) “the Basque case,” 347.

20. Cronin, How Terrorism Ends, 25-26.

21. Zulaika & Murua, (2017) “the Basque case,” 348.

22. Kirk-Smith and Dingley, “Countering terrorism in Northern Ireland,” 556.

23. Jason Gutierrez, “11 Filipino Soldiers Are Killed Trying to Track an ISIS leader,” New York Times, 17 April 2020, available at, (accessed 20 August 2020.). 

24. Cronin, How Terrorism Ends, 27. 

25. Cronin, How Terrorism Ends, 27.