There hasn't been peace in Africa, Asia or the Mid-East since the end of European colonialism. That's a radical statement, and it's going to be unpopular, I'm sure, but it's true.
As much as those on the Left would love to believe the ideal of free people governing themselves peacably, the cold, sad fact is that, for whatever reasons, tribal, political or economic, some people just can't seem to govern themselves.
Look at Central Europe, for example...those people had been fighting for millennia. The only time they had even an uneasy peace was when they were under the thumb of a greater power that came in and told them how it was going to be. From the Romans to the Ottoman Turks, then the Austro-Hungarians, then the Nazis, followed lastly by the Communists. When The USSR fell apart, the old animosities sprouted again, and the fighting started over. So, the UN(mainly meaning the US), had to go in and settle things down.
Africa is the same way. Why shouldn't we train Africans to police Africa? Why should we always have to be the ones to spill our blood to quell the unrest fomented by others? Everyone always looks to the United States to handle things for them (but when we were in our time of need, where were they? You know, Florida could really use some help right now. I wonder how many foreign relief workers there are in Pesacola, right now?). It's ridiculous.
You know, though, the idea of giving African soldiers American citizenship for their service might not be such a bad idea; in fact, that's what the Romans did for their foreign legionaires. But then, they're supposed to be trained for duties policing in Africa; so that's where they should stay.