AP Photo

MAJOR JOHNSON GUCH of the Sudanese People’s Liberation Army (SPLA) sits outside a grass hut at the edge of Nasir, a missionary post in Nuerland that in time became a dismal town (see map). Dressed in a tracksuit, he gives the air of a local warlord. A Nuer himself, Mr Guch is commander of a joint integrated unit (JIU) of southern and northern Sudanese soldiers mandated to keep the peace in Nasir. He says he has 150 southern soldiers, each with a small tin of bullets. But he is dismissive of the northern soldiers. He does not know how many there are. He says he does not care. It is not, in any sense of the word, a joint command.

The commander of the northern troops, Captain Osman Mustafa, is more gracious, but also more disingenuous. His tent is a walk across...