Selecting Success: Recruitment and Insurgent Effectiveness in Civil Wars

Why are some insurgent groups more combat effective than others? With the rise and persistence of the Islamic State of Iraq and Syria (ISIS) and the continued resurgence of the Taliban, understanding what drives differences in insurgent effectiveness has become increasingly important for both academics and decisionmakers. Yet the existing academic literature on combat effectiveness, focusing as it does on ultimate conflict outcomes or conventional armed forces, tells us little about the diverse performances of non-state armed actors during conflict or their relative efficacy at lower levels of capabilities. Moreover, the conventional assumption that insurgent factions with more fighters or higher levels of external support are inherently more effective is not borne out by empirical evidence. In practical terms, the failure of policymakers to anticipate and counter the rise of ISIS indicates the need for clear measures of effectiveness that can inform assessments of insurgent viability in real-time, and provide an understanding of why particular armed groups are more combat effective than others.

I fill this gap by developing a framework that both measures and explains insurgent effectiveness during civil wars. To measure effectiveness, I argue that the balance of capabilities between incumbent and insurgent forces shapes how insurgents should fight, and consequently what constitutes combat effectiveness during conflict. To explain effectiveness, I position the relative rigor of insurgent recruitment practices as key in shaping the effectiveness of groups. Insurgent groups that select, induct, train, and socialize recruits in a consistent and comprehensive manner throughout their areas of operation have what I call robust recruitment practices, which generate the uniform shared purpose, discipline, and interpersonal trust among commanders and fighters needed to fight effectively in combat.

I test this framework through historical case studies of insurgent group performance during the Jordanian Civil War (1968-1971), the Dhofar Rebellion in Oman (1964-1975), and the Eritrean War of Independence (1961-1991). I use existing works, media reports, and archival sources for the Oman and Eritrea cases. For the Jordan case, I draw on thirteen months of field and archival research in Jordan, Lebanon, and the United States. This research includes 105 separate interviews in Arabic conducted with former Jordanian military/intelligence/government officials and ex-insurgent commanders/fighters from the conflict, as well as archival documents gathered from multiple repositories across the three countries. In each case, I demonstrate through process tracing how the relative rigor of a group's recruitment practices shaped its ultimate combat effectiveness. These findings contribute to scholarship on civil wars, violent non-state actors, and military effectiveness, fill gaps in the historical record of Jordan, and have practical implications for counterinsurgency and peacebuilding.