The purpose of this paper is to examine and compare dynamics of joint-decision making in the domain of public security across nine federal countries: Canada, the United States, Mexico, Brazil, India, South Africa, Germany, Switzerland and Spain. While security and order have always been basic to effective governance, economic development and psycho-social trust, over the past ten years security has emerged as a key policy area across democratic federations. In the context of multilevel government, this development has given rise to a tension: on the one hand, security is ultimately local insofar as it reflects the values and priorities of local communities; on the other hand, central governments across federal countries have felt it necessary to overcome perceived collective-action problems at lower levels of government by extending the leverage of central governments in the provision of security. This paper hypothesizes that problems of joint-decision making are a function of different objectives of each level of government: security concerns of central governments, such as counter-terrorism, are quite different from security concerns of local governments whose electorates are more concerned about local crime than national security write large. This makes joint-decision making difficult. Governments have different tools at their disposal to overcome this problem, including financial incentives, legislation and constitutional challenges. This paper examines the tensions around joint-decision making in matters of security, compares mechanisms deployed to overcome impasses, and assesses effectiveness and outcomes. Its objective is to ascertain what sort of multilevel-governance arrangements offer the best joint-decision making mechanisms, and which the least. It the tries to explain these assessments in light of constitutional, legal and institutional structures as well as political culture.