In sub-Saharan Africa, formal regionalism (institutional forms of cooperation or integration) has been increasingly challenged by the development of strong trans-state flows (‘informal’ or ‘network’ integration or regionalization) (Amselle and Grégoire 1988). Despite being closely interrelated, the two forms of regionalism appear to be mutually exclusive because of their different impact on state institutions, territorial legitimacy and adjustment capabilities. Formal regionalism postulates the aggregation and fusion into broader units of existing territories or fields of intervention. Network regionalism (regionalization) is a result of the exploitation of dysfunctions and disparities generated by existing boundaries, with debilitating effects on state territorial control.