Here’s a link to a great article about divisions in Ugandan society. The writer points out the geopolitical rivalries between north and south, and touches upon the tumultuous history of regime change that has led to the current situation in northern Uganda. She does not, however, trace these forces back to their roots, most of which can be found in the policies that the British colonial government used.
It’s important to remember that “tribal tensions” are not some sort of endemic disease of African culture. Imagine what might happen if you were to erase all the borders in Europe and let those countries figure out how to govern themselves as a whole. It would not be pretty. This is what it was like for Uganda in the early 1900s, when many tribes were grouped together under one flag and then employed according to stereotype.
The process of unification and reconciliation will be a historical one, just as the unity between the Union and the Confederates has taken time, and cultural differences remain to this day. But Uganda must unify if it is to thrive.