 Federalism is the theory or advocacy of federal principles for dividing powers between member units and common institutions. Unlike in a unitary state, sovereignty in federal political orders is non-centralized, often constitutionally, between at least two levels so that units at each level have final authority and can be self governing in some issue area. Citizens thus have political obligations to, or have their rights secured by, two authorities. The division of power between the member unit and center may vary, typically the center has powers regarding defense and foreign policy, but member units may also have international roles. The decision-making bodies of member units may also participate in central decision-making bodies. Much recent philosophical attention is spurred by renewed political interest in federalism and backlashes against particular instances, coupled with empirical findings concerning the requisite and legitimate basis for stability and trust among citizens in federal political orders. Philosophical contributions have addressed the dilemmas and opportunities facing Canada, Australia, Europe, Russia, Iraq, Nepal, Ethiopia and Nigeria, to mention just a few areas where federal arrangements are seen as interesting solutions to accommodate differences among populations divided by ethnic or cultural cleavages yet seeking a common, often democratic, political order.