Is targeting the leadership of terrorist organizations an effective counterterrorism strategy? States can employ a number of different tactics in order to weaken and defeat militant organizations - they can use brute force, repression, regime change, negotiations, undermining support, ideological change, cutting off finances, and leadership targeting. While states have employed all of these measures, leadership decapitation - which refers to the arrest or killing of a group's leadership - has become a central component of U.S. counterterrorism policy and reflects the prevailing view among many academics and policymakers that removing a group's leadership inflicts irreparable damage on its capacity to operate.
Attacks against the leadership of al Qaeda, the Islamic State of Iraq and Syria (ISIS), and other militant groups show no sign of decline. It is thus critical to evaluate whether it is an effective counterterrorism strategy, the conditions under which it likely to succeed or fail, or whether it has the potential to result in adverse outcomes.
Between 1995 and 2016, the U.S. killed or captured more than 287 high level al Qaeda operatives in positions of leadership. After Osama bin Laden was killed on May 2, 2011, policymakers and analysts argued that the organization would be crippled. Al Qaeda suffered other significant losses in 2011, including the deaths of Anwar al-Awlaki, Abu Yahya al- Libi, and Atiyah Abd al-Rahman. While core al Qaeda and its affiliates may have suffered periods of decline, these losses did not significantly weaken the organization. The group has continued to franchise with the growth of more affiliates, many of whom, such as al Qaeda in the Arabian Peninsula (AQAP), continue to carry out a large number of attacks.
The U.S. has targeted nearly 60 ISIS operatives since the summer of 2014, and this strategy is likely to continue as long as ISIS remains a threat. Abu Muhammad al-Adnani, believed to be the group's second most important leader after Abu Bakr al-Baghdadi, was killed by an airstrike in Aleppo, Syria in August 2016. He was one of the group's longest-serving top commanders - a spokesperson for ISIS who handled operations outside of Syria and Iraq and was responsible for the recruitment of foreign fighters. His death was considered by many to be a major blow to the organization. Prior to his death, Adnani claimed that while ISIS may experience periods of weakening, the movement is fundamentally ideological and is larger than its capacity to control territory. ISIS has lost considerable amounts of territorial control in Iraq and Syria, yet the organization remains active and a major regional and international threat.
The use of unmanned aerial vehicles (UAVs) has become a low cost means of targeting militants, increasing the likelihood that decapitation will remain a widely-used tactic. While it is clear that a large number of missions have been successful in killing or capturing their intended targets, there is considerable disagreement regarding the effectiveness of decapitation in destabilizing militant groups, particularly since there is a lack of consensus over how to assess and measure the efficacy of a counterterrorism policy. A successful counterterrorism strategy requires clear, consistent goals and appropriate measures through which to evaluate those objectives.
In order to develop successful counterterrorism policy, it is essential to understand why targeting is effective in some cases and not in others. I have argued in previous research and in a forthcoming book that this variation can be accounted for through two primary variables: bureaucracy and popular support.
Groups that are bureaucratized and those that have high levels of popular support from the communities in which they operate are more likely to survive leadership targeting. Bureaucratized organizations have an easier time reorganizing after the loss of their leaders, because they have clear succession mechanisms and standard operation procedures that enhance their resilience. Groups with significant levels of communal support have access to resources that allow it to withstand attacks and to continue carrying out activity. Moreover, the ideology upon which these groups are based often doesn't depend upon the leadership for its articulation.
In order to determine whether targeting is an effective policy, I examined nearly 1,300 instances of leadership targeting from 1970-2016 and 290 terrorist organizations. The data suggests that overall decapitation is not an effective counterterrorism policy. Targeting does not increase the likelihood of a group's demise or shorten its lifespan. It does not result in a reduction in the frequency with which organizations carry out attacks, and in certain cases, it can have counterproductive consequences, emboldening an organization, increasing its activity, or enhancing its ability to acquire more recruits.
There are specific conditions under which decapitation is more or less likely to result in a decline in activity or increase the rate with which a group can fall apart. A group's size, age, and type can impact the trajectory of these trends. Targeting is unlikely to result in the significant weakening of larger groups; older, religious groups; separatist groups; and specifically Islamist groups. Certain characteristics of the home state in which the group is primarily based, such as population and GDP, can also impact the efficacy of decapitation. The most active organizations saw an increase in activity after decapitation.
In certain cases, decapitation can result in a decline in activity or hasten a group's demise, but it is unlikely to be effective against groups that continue to be the target of frequent decapitation efforts, such as ISIS, al Qaeda, Hamas, al Shabaab, or the Taliban. These groups receive considerable amounts of popular support from the communities in which they operate and possess bureaucratic characteristics, making them harder to destabilize.
Undermining support for these groups is essential. For example, providing social services in communities where militant groups operate could eliminate opportunities for groups to gain further local support. It is thus essential that policymakers not only identify clear metrics by which to evaluate the efficacy of counterterrorism policies, but also recognize that leadership targeting alone is not likely to significantly weaken a terrorist organization.
