What happened after Africa's biggest country split in two? When South Sudan ran up its flag in July 2011, two new nations came into being. In South Sudan a former rebel movement faces colossal challenges in building a new country. At independence it was one of the least developed places on earth, after decades of conflict and neglect. The 'rump state', Sudan, has been debilitated by devastating civil wars, including in Darfur, and lost a significant part of its territory, and most of its oil wealth, after the divorce from the South. In the years after separation, the two Sudans dealt with...