Failed states--countries in which governing institutions have corroded or collapsed-- are considered by many scholars to pose a grave threat to global security. Policymakers broadly share this view. The United States' 2002 National Security Strategy flatly declared that "America is now threatened less by conquering states than by failing ones", while the United Nations warns of the global dangers posed by states that cannot meet their responsibilities as sovereign powers.The conventional wisdom on the risks posed by failed states represents a significant shift in international relations scholarship, which has traditionally emphasized the threat that strong states pose to weaker polities. It also represents a shift in foreign policy, as fear...