Of course you would have to make it appear that the oppression is the idea of the people, not the government. It would take approx. 60+ years to purge the population of hatred and prejudice, put the oppression would keep the dissidents at bay, while the general population heals.

You could also replace the hostilities with a more common, though far more benign, enemy. A powerful, centrally run, dictator-government, but one with a secret agenda for democracy. Give the people everything they need (free medical, plenty of grocery stores, cable and satty TV), but benign them any choice in government. 60 years from now, allow a quiet little coup, and the birth of democracy.

Cutting the land up for local warlords creates the "brushwars," which extend animosities through generations. For actual peace, you need to kill this mindset, not fertilize it. The practice is illegal for the U.S. to participate in, since this would involve setting up a dictatorship -- but, medically, healingly speaking, I think it would work...

Dan