American Political Science Review
This article studies variation in conﬂict theater choice by Western jihadists in an effort to understand their motivations. Some militants attack at home, whereas others join insurgencies abroad, but few scholars have asked why they make these different choices. Using open-source data, I estimate recruit supply for each theater, foreign ﬁghter return rates, and returnee impact on domestic terrorist activity. The tentative data indicate that jihadists prefer foreign ﬁghting, but a minority attacks at home after being radicalized, most often through foreign ﬁghting or contact with a veteran. Most foreign ﬁghters do not return for domestic operations, but those who do return are more effective operatives than nonveterans. The ﬁndings have implications for our understanding of the motivations of jihadists, for assessments of the terrorist threat posed by foreign ﬁghters, and for counterterrorism policy.