The subversion of democracy in former French colonies in Africa stymies the African Union from developing from a mere confederation, wherein all of the governmental sovereignty resides with the states, to modern federalism, whose chief characteristic is dual sovereignty. There is good reason for the requirement in the U.S. that the states be republics rather than dictatorships, for the latter would be more likely to ignore the federal jurisdiction within their respective states.
The full essay is at "Democracy Waning in Africa."