The East African Federation is a proposed political/economic union of Burundi, Rwanda, Uganda, Kenya, Tanzania, and South Sudan. These countries form a physically contiguous block, speak similar/overlapping languages, and have similar climates and terrain. They seem like a match made in heaven for a federation and economic/currency union. But South Sudan seems the odd man out, being by far the poorest members and still rather dangerous and unstable because of ongoing conflicts with Sudan. Meanwhile Malawi appears to be an excellent match for the EAF in all the ways listed above, while being far more stable and less poor than South Sudan. So why isn't Malawi in the EAF?
This same question has already been asked and answered about Somalia, but Somalia doesn't seem like a fit for the EAF at all, even if it weren't in chaos.