In the wake of the Syrian conflict and the terrorist attacks in Paris and Brussels, the reaction from European national governments has varied widely. While some have taken sweeping measures, others remain more cautious. Is there a common European approach to counterterrorism and, if so, is it working? How can cooperation in this area be improved? Have European measures to stop the flow of foreign fighters to conflict zones been effective? What role can prevention and de-radicalization play in countering the emergence of new terrorist networks?