HARDtalk's Stephen Sackur speaks to Riek Machar, South Sudanese Vice President turned rebel leader. For the people of South Sudan five years of independent nationhood have brought little more than impoverishment, violence and suffering. The world's newest nation is again racked by internal conflict. More than a million people have been forced from their homes and the country's president Salva Kiir, and his nemesis Riek Machar are again at each other's throats. Has South Sudan been betrayed by its leaders? Show less