The vice-president of the new country, Riek Machar, an ethnic Nuer, has already been sidelined.

ECONOMIST: Sudan's separation

Sudan troops are now in control of the region, but if they continue with attacks, South Sudan will retake it, said Riek Machar Teny Dhurgon, the South Sudanese vice president.

CNN: STORY HIGHLIGHTS

McCune might have remained a footnote, another addition to the long list of humanitarians who, for at least a century, have become involved in Sudan for reasons often half-hidden from themselves, had it not been for her sudden marriage to an African warlord named Riek Machar, or Dr Riek as he was known to his followers.

ECONOMIST: Africa is a continent made for??and of??storytellers