Regional organizations have become an increasingly significant feature of the international system, and they are also increasingly developing external relations with other regional organizations. Thus far, state-centric IR theories have been used to try to explain these region-to-region relationships, but with poor results. The problem with applying state-centric theories is that it makes the implicit assumption that regional organizations are unitary actors, like states, when we know that – in reality – this is not the case. This paper attempts to address the ‘actor problem’ in the study of interregionalism. It avoids the overly simplistic distinction between supranationalism and intergovernmentalism in favour of a conceptual model of actorness based on the material, ideational, and institutional aspects of regional organizations. The model is then applied to two case studies: the Southern African Development Community (SADC), and the Economic Community of West African States (ECOWAS). Preliminary findings suggest that, although both regional organizations have relatively low actor capabilities, ECOWAS is the stronger actor of the two.
