9/11 has reinforced the discursive securitization of migration and integration politics and policies in major immigration countries, the so-called migration-security nexus. To explore this argument, the analysis deals with three propositions. First, the end of the Cold War has opened political space for focusing on diffuse and hard-to-grasp security threats that do not emanate from sovereign states but from non-state actors, involving issues such as crime, drugs, migration. International migration has served as a convenient reference point for unspecific fears. Second, securitizing policies such as stepped-up border controls and stricter internal surveillance of immigrants produces unintended effects. Securitizing policy issues creates higher expectations among voters that governments are actually able to effectively control transnational movements. Third, 9/11 entails ambiguous consequences for immigrant integration. Clearly, the levels of harassment against immigrants from the Middle East increased considerably, at least on the short term. Yet the crisis situation may even lead to an increased immersion into the politics of the respective national immigration states. General attitudes and policies towards cultural pluralism will probably not be significantly affected by 9/11. Overall, the exploration of the migration-security nexus is part of broader studies into the virtuous and vicious cycles of transnationalization, the growing importance of non-state actors in world and national politics.