The Impact of Foreign Fighters on Terrorist Group Behavior

• In Event: Terrorist Group Decision-Making: Trends in Tactics, Rhetoric and Exit

Abstract

How do foreign fighters affect terrorist group behavior? Recent studies have examined the impact of foreign fighters on conflict outcomes, but although foreign fighters may have an impact on such macro-level outcomes, we argue that their more proximate impact will be to change how groups they join behave. More specifically, we posit that the ideological, tactical, and resource dynamics introduced by foreign fighters are likely to impact terrorist groups’ operations, specifically by increasing their frequency and lethality as well as expanding their geography reach. Using data on foreign fighter participation in terrorist groups together with various metrics of terrorist group behavior, we conduct a quantitative analysis to examine our arguments. This paper contributes to the understanding of foreign fighters by providing nuanced group-level data and offers an important theoretical understanding regarding the positive and negative impacts such fighters can have on terrorist groups. Additionally, these results provide important insight for policymakers by showing how foreign fighters are likely to affect group behavior once they become a part of the organization.

Authors

• Daniel Milton, United States Military Academy

• Tricia Bacon, American University