This is particularly dangerous in a society with a whirl of centrifugal forces -- the existence of 150 tribes, a long history of SPLM infighting, and a tendency for North Sudan to fund and encourage internal conflict within the South.
In a new and fragile state, a great deal depends on the governing style of its first leader. Either a Mandela or a Mugabe may emerge, which places South Sudan in a unique position. The founder of the independence movement, John Garang, died in a plane crash in 2005. Garang was a charismatic, educated, Marxist-turned-Christian, rebel leader -- a man who viewed tribalism as historical dead wood and wanted to lead southern Sudan into the modern world.
South Sudan's first president, Salva Kiir, provides a vivid contrast in leadership. Kiir models himself on the chiefs of his tribe, the Dinka. It is an aristocratic, gentlemanly tradition, in which power is exercised through layers of leadership. While Garang could be abrasive, Kiir is more oriented toward consensus.
Other tribes within South Sudan sometimes resent the aristocratic airs of the Dinka. But so far, Kiir's approach has served him well. After Garang's death, the SPLM broadly accepted the legitimacy of Kiir's succession. He has successfully reintegrated many powerful adversaries from the time of the war back into the party.
But Kiir has a challenge. Large-scale corruption has its own internal logic. It will not, however, result in development. And while Kiir himself is not seen as corrupt, he is broadly criticized for tolerating corruption around him.
In his fine inaugural speech, Kiir was both gracious to enemies -- offering rebels full amnesty -- and tough on official corruption. But fighting corruption -- high profile prosecutions and the recovery of diverted funds -- requires the making of enemies. And Kiir's efforts may be undermined by the consensus he has cultivated.
The independence of South Sudan is a large, unlikely achievement. But now it faces among the hardest of historical tasks: The liberators of a nation must become the founders of a nation.