Ethnic federalism, multi-ethnic or multi-national federalism, is a form of federal system in which the federated regional or state units are defined by ethnicity. Ethnic federal systems have been created in attempts to accommodate demands for ethnic autonomy and manage inter-ethnic tensions within a state. They have not always succeeded in this: problems inherent in the construction and maintenance of an ethnic federation have led to some states or sub-divisions of a state into either breaking up, resorting to authoritarian repression, or resorting to ethnocracy, ethnic segregation, population transfer, internal displacement, ethnic cleansing, and/or even ethnicity-based attacks and pogroms.