The great hope for cooperation after the vote for southern independence.

Bentiu, Sudan—Two days ago, President Omar Al Bashir made what is likely to be his last visit to Juba, the southern capital, as the head of a unified Sudan. Promising to be “the first to recognize the south” if southerners vote for independence in this weekend’s referendum, Al Bashir’s conciliatory tone left people here scratching their heads about his real intentions. Mistrust of his ruling National Congress party is intense in the south, and, until last week, officials in Khartoum had been uniformly hostile about the possibility of secession. But there was a not-so-subtle subtext in Al Bashir’s comments, namely his pledge to “cooperate and integrate in all areas because what is between us is more than what is between any other country.” What he was really talking about was oil.

(Read Rebecca Hamilton’s first Sudan Dispatch: “Is the End in Sight?”)

Both the northern and southern governments need Sudan’s oil to survive financially. The government in Khartoum currently gets 60 percent of its annual budget from oil revenue, while, for the southern government, the figure is 98 percent. And nearly 80 percent of this lucrative oil comes from here in Unity state, which will soon be part of a new, independent South Sudan, if the vote goes as expected.

Unity state used to be known as Western Upper Nile—that was, until oil was discovered here. As part of a redistricting of the south, Khartoum renamed the area Unity, as if, by labeling alone, this most oil-rich part of the south would be forever connected to the north. For most of its history, however, Unity has been the antithesis of its name. During the most recent civil war, Khartoum supported a variety of splinter southern rebel groups based here who were locked in battle with the Sudan People’s Liberation Army, the main southern rebels. Indeed, much of the civilian life lost in this area did not come from direct north-on-south violence, but from a coalition of Sudanese government soldiers, Khartoum-backed rebel groups, and oil companies, which worked to “secure” the oil fields for Khartoum’s benefit. This meant clearing the land—and, with it, the people who lived here.

Now, with just two days to go before southerners finally vote on independence, Unity state is on the brink of a new era in its history. Instead of being a battleground, it could potentially play a crucial role in keeping the north and an independent south from returning to war. While technically, the oil here would belong to the south, the pipeline that exports it runs through the north. The need to keep selling oil to the outside world gives both the north and south a strong incentive to maintain good relations.

At the Unity oil field on Thursday, I met a mix of Sudanese employees, working as drivers, cooks, and floor managers, alongside Chinese engineers. As dusk fell, the northern Sudanese set up their prayer mats beside their on-site accommodations, kneeling against the backdrop of a giant oil rig. One of these workers, who asked not to be named, said that southern government officials had recently visited the rig to reassure the employees that, even if secession happens, there will be no disruption to their work. “It is in everyone’s interest,” the worker recalled the officials saying, “to keep the oil flowing.”

Rebecca Hamilton is the author of Fighting for Darfur and a fellow at the New America Foundation. Her Sudan reporting is supported by funding from the Pulitzer Center.