Ongoing negotiations over the implementation of the stalled peace deal signed between Sudan and South Sudan in September have resumed once more in Addis Ababa with the two countries' ministers of defence meeting to discuss the question of security on the border.
Establishing a demilitarised zone could help establish the underpinning principle of this peace deal, namely that it is in their mutual interest – both politically and economically – to put down their weapons and start cooperating. But no one is holding their breath.
Last week they met in Khartoum, Sudan's capital, for barely 24 hours in what was supposed to be a two-day meeting with no progress made.
Before that, in November, in Juba, South Sudan's capital, two days of talking ended in not much more than the agenda being discussed. Some of the Southern Sudan People's Liberation Army (SPLA) generals simply refused to be associated with the Addis agreement. They said they never signed it and want nothing to do with it, according to multiple sources with knowledge of the meeting. Attempts to get the South's civilian leadership to pull rank failed. Efforts to get President Salva Kiir to intervene came to nothing, sources said.
Why? Well, things are not so easy in Juba right now. A few weeks ago President Kiir publicly ticked off potential coup plotters in the military, warning them no one in the international community would recognise them if they took over. He is not generally known for forcing showdowns with political rivals.
"The problem is he doesn't have the type of personality that will take people on, and deal head on with these kind of problems," confided one western diplomat who rated Kiir's current chances of remaining in power as fifty/fifty.
Even the toughest of presidents would be struggling right now in South Sudan. It has no money to pay its civil servants, its police and most importantly - in view of where there is most discontent - its army.
This turn of events was self-inflicted, critics say. A year ago South Sudan was a pre-industrial economy with a sugar daddy called oil. Now it is just a pre-industrial economy. Back in January, South Sudan's leadership turned off its entire oil production in a fit of anger with Sudan.
Sudan controls the pipelines to the sea and it had started helping itself to some of the oil in lieu of unpaid transit fees after months of failed negotiations over the rate. There is now a signed agreement on this issue, but like other key parts of September's agreement, it has yet to be implemented. Meanwhile, the South has no income.
No security, no oil
Getting the oil flowing is the one hope for improving the currently grim outlook in Sudan and South Sudan. Paul Jenkins, head of the International Monetary Fund in Sudan, said: "The recent oil agreement is very much a win-win for both parties, and it's in the economic interests of both sides to implement as soon as possible."
While Sudan needs the dollars it will get from transit fees - its economy is in a parlous state, after losing 75 percent of oil production when the South split - it is not as bad as its southern neighbour.
"Getting oil back on is important for Sudan but it's critical for South Sudan," said one foreign economist. "It's true that oil revenues from the South were 56 percent of Sudan's government revenues before Independence but for South Sudan it's the whole ball game. There isn't anything else."
Khartoum has exploited this difference in desperation over oil to try to get something it wants even more: to stop Juba supporting a rebellion on its border states of South Kordofan and Blue Nile. Unless it gets this, Sudan has long made clear in this negotiation, the oil will not flow.
The demilitarised zone, over which these repeated talks have been held, was supposed to stop this. It involves monitors and verification of any cross-border activity. But this is no longer enough for Khartoum and it is making new demands.
Sudan's President Omar Bashir now wants South Sudan's army, which is still called the Sudan People's Liberation Army, to actively disengage from the Sudan People's Liberation Movement North (SPLM N), pull back its weaponry and supplies from South Kordofan and Blue Nile, and expel any SPLM N members from Juba.
The US Special Envoy, Princeton Lyman, told a press conference in Juba on Friday he finds these new demands "troubling".
"It's not absolutely clear what kind of additional assurances would be more important or more effective than demilitarising the border and setting up a joint monitoring of the border crossing points," he said.
President Kiir, who officially denies supporting these rebels across the border, has dismissed this as an "impossible mission".
"You cannot imagine that a foreign army can cross to another country to go and conduct disarmament. That can't be. It will not happen," Kiir has said.
Many would question whether or not the SPLA and SPLM N are really foreign armies to one another. Until July 2011, what is now called the SPLM North was actually the ninth and tenth division of the SPLA - South Sudan's army. For President Kiir's generals they are not rebels: they are former comrades, and ideologically many of them continue to support the aim of regime change in Khartoum.
One source close to the Sudanese government believes a face-saving formula will be found at the current talks. "There are ways of appeasing these [SPLA] generals. Maybe it can't be done publicly, but for its own legitimacy, Juba needs to be seen to drop the SPLM N."
But if President Kiir can't do it, if he is unable to effectively pull rank over his generals who don't want to implement this demilitarised zone nor abandon their former comrades, what are the alternatives?
Resolve the conflict?
Those involved in trying to resolve this impasse see the answer as a political solution to the conflict between the SPLM N and the Sudanese government. "If there were a political process that stopped the fighting in Southern Kordofan and Blue Nile, that too would alleviate that problem," Ambassador Lyman said. Getting a border zone in place would be the other key factor, in his view.
But the Sudanese government has publicly stated it is not currently prepared to negotiate. Vice President Dr Al Haj Adam Youssif ruled out talking to the SPLM N until there was clear evidence that their ties to Juba had been cut. "They have to come to us as Sudanese, not representing the South Sudanese army," he said.
The reason why it is so difficult now for talks to publicly take place for Khartoum, is that like its Juba counterpart, it has its own domestic issues. Not only is the economy steadily diving and inflation rising - there are also political tremors. Last month, several prominent insiders were arrested for allegedly plotting a coup, and over the past week in Khartoum and elsewhere there have been daily protests at universities about the mysterious deaths of three Darfuri students.
In this environment, it is hard to see the Sudanese government producing a deal with the SPLM N without being eaten alive by hardliners who believe the government has already given too much away: not only has it lost the South, but if the African Union proposal goes ahead, it's in danger of losing the disputed territory of Abyei too.
The one thing that would strengthen Sudan's hand against its critics right now is to get the oil turned back on. This would ease political pressure, and stablise the economy. But to do that Juba must stop supporting the SPLA N. And Juba is in no position to do that because its civilian leadership cannot take on its generals…
While both governments put their necks on the line with their hardliners to sign this deal, neither of them - as they are ably demonstrating - will commit hara-kiri to implement it. The only hope is that they come to believe that, far from being the path to their destruction, implementing this deal, will actually be the thing that saves them.