From the grass stalls of Bentiu, where a burnt market and upended billboard bear scars of air strikes, South Sudan’s road north to Sudan buzzes with the locomotion of war. To the left and right, oil fields lie pocketed with shrapnel-filled craters. Civilians with chairs or beds on their heads stream south, as trucks full of South Sudanese soldiers and Darfur rebels rumble back and forth. Our convoy, escorted by the South Sudanese army, blows by the town of Lalop — emptied of civilians and teeming with soldiers, tanks, and anti-aircraft guns. Further ahead, we pull to a stop at a smaller encampment of grass huts and foxholes.