The EAC is not different from the AU which aims at integrating all African states.  All countries that have shown interest in joining the EAC are member states of the AU which oversees integration in African countries; there is no reason then for them to join another bloc that has the same aim as the African Union unless it is no longer functioning.  Countries like DRC and Sudan are geographically located in different regions than East Africa and this would breach the meaning of the bloc. Additionally, these individual countries are members of other regional organisations like COMESA and SADC which puts a challenge of flexibility in adopting different policies from separate blocs. [1] For example how could a customs union operate if DRC were to be a member of two separate customs unions? any external barriers between the two could be bypassed by going through the DRC.  [1] Dinka,T,Kennes,W, ‘Africa’s regional integration arrangements; history and challenges’, ecdpm.org, 2007,