Today, I try to provide a (historical) survey of the rationalisation, and offer an explanation of why it is key to Africa's integration. It's no lecture, so keep your eyes wide open!
Unlike the EU integration efforts that saw expression through the European Coal and Steel Community of 1957 to enlargement, through to the Treaty of Maastricht that created the European Union, AU integration efforts is of a rather different ilk.
You might re-call that Africa is made up of 53 countries. With the exception of Morocco, all the member states--notably 52 countries--make up the African Union by virtue of being member states of the continent.
In 1991, the Treaty of Abuja established the African Economic Community (AEC), which came into force in May 1994. There are 6 stages through which the AEC will come into fruition:
1. (to be completed in 1999) Creation of regional blocs in regions where such do not yet exist
2. (to be completed in 2007) Strengthening of intra-REC integration and inter-REC harmonisation
3. (to be completed in 2017) Establishing of a free trade area and customs union in each regional bloc
4. (to be completed in 2019) Establishing of a continent-wide customs union (and thus also a free trade area)
5. (to be completed in 2023) Establishing of a continent-wide African Common Market (ACM)
6. (to be completed in 2028) Establishing of a continent-wide economic and monetary union (and thus also a currency union) and Parliament
Now, the AEC is already in operation, but it needs some flesh to make it more substantive. This is where the Regional Economic Communities come into the picture. They are there -- not because they were plucked from the air, but primarily because Africa had many groupings already even before the erstwhile OAU became the African Union in 2002.
ECOWAS was established in 1975; SADC's origins begun in 1980; COMESA's origins begun in 1981; Arab Maghreb Union, 1989; CENSAD in 1998; EAC in 2000 ; IGAD in 1986; ECCAS in 1985.
Looking at the dates, we can clearly see that all of the RECs were in existence long before the establishment of the AU.
To cut a long story short, three important meetings held in Accra(2005) & Zambia(2005); Burkina Faso(2006); and the AU Summit in 2006 in The Gambia all paved the way to ensuring that there was what is known as a "rationalisation" of the RECs. Some of the official documents point to the RECs being "federative poles" of the AEC. Most would simply understand this as "pillars".
Given that there are sub-regional groupings(SRECS) within all these groupings--such as Mano River Union; UEMOA in West Africa; CEMAC in Central African region--there was a need to ensure that the multiplicity of groupings be made simpler to deal with, especially with an African Union that needed less complication on its hands by dealing with no less than 14 groupings in total, which the UNECA recognised.
In effect, rationalisation has come to mean boiling the groupings down to qualities that could be easily identified with. The UN Economic Commission for Africa came on board--as did the African Development Bank. In consultations, the following was recommended.
Though this list was reduced considerably in the subsequent meetings in 2006, it at least offers a serious insight into some of the discussions that transpired some four years ago before the AU Summit in The Gambia in 2006 finally recognised the eight RECs, which have also been "endorsed" by no less than the UNECA.