In the immediate aftermath of major attacks in Paris, counter-terrorism raids in Belgium saw two suspected terrorists killed and another arrested. These incidents have dramatically raised the sense of insecurity across Europe – and they’ve done so at a time when Europe’s security infrastructure is struggling to cope with the threats it faces. European security agencies, both internal and external, must urgently improve their cooperation and coordination. After all, Europe’s security challenges know no borders, and they must be dealt with as such.