International migration has moved to the top of the international security agenda, due in part to concerns that migration flows provide conduits for the spread of international terrorism. Although such concerns are not entirely unfounded, they must be placed within the broader context of the range of impacts—both positive and negative—that international migration flows have on states' core national security interests. Migration flows affect at least three dimensions of national security: state capacity and autonomy, the balance of power, and the nature of violent conflict. Overall, migration management presents a far greater security challenge to weak and failing states than to advanced postindustrial states. States that are able to formulate and implement migration policies that harness the power of international migration will be more secure, rather than less secure, in the new globalized security environment.