How Migration Policies Moderate the Diffusion of Terrorism

There is an ongoing debate among practitioners and scholars about the security consequences of transnational migration. Yet, existing work has not yet fully taken into account the policy instruments states have at their disposal to mitigate these, and we lack reliable evidence for the e↵ectiveness of such measures. The following research addresses both shortcomings as we analyze whether and to what extent national migration policies a↵ect the di↵usion of terrorism via population movements. Spatial analyses report robust support for a moderating influence of states’ policies: while larger migration populations can be a vehicle for the di↵usion of terrorism from one state to another, this only applies to target countries with extremely open controls and lax regulations. This research sheds new light on the security implications of population movements, and it crucially adds to our understanding of governments’ instruments for addressing migration challenges as well as their e↵ectiveness.