M7 has no way out. He got in to power thanks to the Baganda. The Baganda had sponsored Amin and did give him all the support he needed after he overthrew Obote.
When Obote rigged himself back in to office using a Muganda ( Paul Muwanga), the Baganda turned to Museveni. They expected him to return the mkono and let them get the taste of power they have longed for for too long. He just can't.
If he ever allows free and fair elections, he will be gone before 40% of the vote is counted. Museveni has been steadily losing voters over the years - even with rigging included. Logically, he cannot overcome the opposition this time and must find a way of rigging. He knows that Besigye and his former PM will eventually merge in to one and that scares the shit out of him.
What I never understand is why the opposition thinks it can only campaign by having rallies. Since Museveni eventually allows all his opponents on the ballot, why can't they change tactics?
Some resource material for anybody who is interested:
[pdf]http://ifra-nairobi.net/wp-content/uploads/2013/12/4Bwana.pdf[/pdf]
GROUP---------- %
Baganda--------------- 16.2
Bagisu------------------ 5.1
Iteso -------------------- 8.1
Acholi ------------------- 4.4
Basoga ----------------- 7.7
Lugbara -----------------3.6
Banyankore------------- 8.0
Banyoro------------------ 2.9
Banyaruanda------------ 5.8
Batoro -------------------- 3.2
Bakiga -------------------- 7.1
Karamojong ------------- 2.0
Lango --------------------- 5.6
Others (est.)------------- 20.3