DALDOKO, Sudan -- Four months ago, U.S. Secretary of State Hillary Clinton was widely praised for helping to orchestrate an agreement between Sudan and South Sudan that everyone said would help halt the economic implosion of both countries, then locked in a standoff over what share Sudan should have in oil produced in South Sudan.

But now, with South Sudan on Wednesday marking the second anniversary of the referendum that led to its independence, the country’s oil rigs still sit idle and Sudan still refuses to let its oil flow north to the sea.

The reason can be found here, deep in Sudan’s Nuba Mountains, where Africa’s longest-running war still rages, largely out of sight. A charred tank smolders from a recent battle. Corpses, some baby-faced, dot the golden fields and rocky hillsides. The air stinks. A victorious band of rebels gloats.

First Lt. Ambani Silik Kafi, a weathered rebel veteran of Sudan’s civil wars, strolls to the edge of upturned dirt, where he says the rebels have buried Sudanese military officers. As for the rest: "There’s not enough time to bury them."

His face beams in a cascade of creases as he lists the equipment his men have captured. "Bashir keeps bringing us gifts," he said, referring derisively to Sudanese President Omar Bashir. "In the first war, they (army soldiers) fought hard. But this time, they just run away."

A besieged city, Kadugli, capital of Sudan’s South Kordofan province, can be seen in the distance. A rebel soldier, Deflla Kuwa, urges the driver of a white Land Crusier to go slowly. "If they see the dust from the vehicle, they’ll start shelling," he warns.

From the outside, the weary diplomatic scramble to right the sinking Sudanese and South Sudanese ships pivots incessantly around one issue: oil, shut off last year in a dispute over shipping fees and escalating tensions.

But the real cause of the ongoing diplomatic stasis is far more complicated than just the question of how much landlocked South Sudan should pay Sudan for allowing the transshipment of oil to the Port of Sudan for export. The old Sudanese civil war, the one the separation of the Sudans was supposed to end, continues on, truncated but more ferocious than before, say rebels. With the Sudanese government losing, diplomats admit there is no clear end in sight.

The final barriers to restarting oil production technically were removed in August, when Sudan and South Sudan agreed on a host of financial and security arrangements. The deal was brokered by former South African President Thabo Mbeki, with U.S. officials crediting Clinton personally for an aggressive last-minute push on South Sudanese President Salva Kiir to accept the deal.

The deal included a demilitarized border, but thanks to the Nuba rebels and their allies in Sudan’s Blue Nile state, Bashir’s government only controls half of its side of the Sudan-South Sudan dividing line.

So now Bashir has levied an additional demand, to the frustration of diplomats and South Sudanese officials alike: South Sudan must disarm the rebels inside Sudan’s territory first.

The obsession with linking South Sudan to the insurgency strikes the rebels as odd. Their South Sudanese friends won independence. Now their own liberation war must continue, they reason, and their 20,000-strong Nuba rebel force has nothing to do with their new sovereign neighbor.