A man gathers branches to rebuild the roof of his house in Abyei, a contested oil-rich region on the border between North and South Sudan
By Martin Plaut
BBC Africa analyst
On the fifth anniversary of the signing of a deal ending decades of war between north and south Sudan, US President Barack Obama's special envoy has commended the agreement as "the foundation of peace."
"The Comprehensive Peace Agreement has survived through five years of sometimes acrimonious dissent between the parties and it has prevented a return to war," General Scott Gration told the BBC.
However, the general's remarks came after 10 charities issued a report warning that the Comprehensive Peace Agreement (CPA) is in danger of failing, and that Sudan could slide back into war.
General Gration acknowledged the aid organisation's findings, saying that north and south Sudan are "far behind in their implementation of the most contentious provisions of the CPA."
The general also warned that the peace agreement expires in 2011 and that many of its provisions have still not been implemented.
The CPA, signed on 9 January 2005, ended a war that had torn Sudan apart.
Apart from a period of peace between 1972 and 1983 Sudan had been at war since independence in 1956.
More than two million people died, and four million were forced into exile.
Despite obstacles, setbacks and missed deadlines, the agreement has remained intact.
Analysts point out that meaningful progress is essential over the coming year.
There are two key deadlines: April 2010, when nationwide elections are due to be held (already having been postponed from July 2009) and January 2011, when a referendum will decide whether the south should remain part of a united Sudan, or become an independent state.
A new report from the Royal Institute for International Affairs supports the general's more optimistic tone.
President Bashir opposes independence for South Sudan
Its author, Edward Thomas, argues that the CPA is "resilient" despite a lack of trust and frequent arguments between the two sides.
He says the agreement has established an "unprecedented kind of constitutionalism, of two governments without popular mandates, based on and backed by two armies that fought each other for two decades."
Mr Thomas points out that the CPA survived the death of the southern leader John Garang in 2005, and the indictment of the Sudanese President Omar al-Bashir by the International Criminal Court in 2009.
Northern and southern elites have repeatedly taken matters to the brink, before pulling back at the last moment.
For example, it took days of intensive talks last December between President Bashir and the southern leader and Sudanese Vice-President, Salva Kiir, to finally reach an agreement on the law governing the 2011 referendum.
Both the election and the referendum could increase tensions.
The political leadership of the southern Sudan People's Liberation Movement are due to meet next week to decide whether to back Omar al-Bashir for the presidency in April 2010, or to put up their own candidates in conjunction with a range of northern political parties.
Based on current trends, the south is likely to vote for independence in 2011, threatening to take Sudan's oil-wealth with it.
President Bashir's government, as well as neighbouring Egypt, have expressed their opposition to the establishment of an independent southern state.
There are a number of reasons for optimism, including:
- The United States is fully engaged in the region, with General Gration adopting a less confrontational tone with the Sudanese government, seeking consensus where possible.
- The United States and its allies are providing technical and legal advice, as well as applying political pressure when setbacks occur.
The African Union is considering Mr Mbeki's role in the Panel for Sudan
- The former South African President, Thabo Mbeki, is expanding the remit of the Panel for Sudan given to him by the African Union to deal with the CPA as well as the civil war in Darfur.
- Addressing the UN Security Council on 22 December 2009 over the agreement between north and south Sudan, Mr Mbeki said the "panel will interact with these two parties to the CPA to help accelerate the process towards the completion of the agenda detailed in this agreement."
- The United Nations peacekeeping operations in Sudan - one in Darfur (with the African Union) and another overseeing the CPA - are both in place with most of their men and equipment.
- While they still complain of a lack of helicopters and point out that they could not halt any serious north-south conflict, the UN presence does provide a degree of re-assurance and stability.
However major obstacles remain, perhaps the largest of which is Darfur, where an armed stalemate continues.
Talks between the Sudanese government and some of the rebel movements were due to resume in December, but will now take place later this month.
The United States is attempting to bring the groups together.
Members of Sudan Liberation Army (SLA) carry weapons, as do many civilians
"Aside from some notable holdouts of rebel forces, we believe that all parties to the conflict in Darfur are showing a greater willingness now to address the root causes of conflict than at any time in the past," said General Gration.
Edward Thomas, of the foreign affairs think tank Chatham House, warned that American involvement in settling the country's crises carries dangers.
"US mediation may mean that Sudan is not seeking to redefine itself through engagement with its peoples or its neighbours, but is looking to the superpower to set out a solution," Mr Thomas told the BBC.
Clearly 2010 will be a critical year for the country and the wider region, with as many possibilities for failure as success.