By Jeremy Clarke and Andrew Heavens
JUBA/KHARTOUM (Reuters) - North and South Sudanese awoke in separate nations Sunday, relieved at the ease of the split but no closer to solving rows over borders, oil sharing and other issues that may yet spark conflict.
Even within the new boundaries, challenges abound. The north, with its restive rebels, must rapidly plug a gap left by losing most oil resources to the south. The south has to build almost from scratch a nation that is riven by tribal violence.
The creation of the Republic of South Sudan Saturday, the climax of a 2005 peace deal that ended decades of war between north and south, went remarkably smoothly.
Under the surface, though, the crowds were actually watching a messy divorce -- one where the two parties had not reached a proper legal settlement before going their separate ways.
John Prendergast, of the Enough Project, said the ceremony itself was secondary. "I think the relevant question is when are they going to make the comprehensive deal on oil revenues and where the border is. Everything else is window-dressing."
On the day itself, the countries put on a good show. South Sudan President Salva Kiir stood side by side in the southern capital Juba with his old foe, the President of Sudan Omar Hassan al-Bashir, and both made friendly speeches.
The cracks showed seconds after the northern president's address, when a lone voice in the crowd shouted "Bye, bye."
It was impossible to miss the bitterness left by years of war that hints at the acrimony likely to plague future negotiations.
"Any sharing a country with Arabs or Muslims is like sharing a country with devils," said southerner Simon, 34. Another's T-shirt read: "I've got 99 problems but Bashir ain't one."
As the celebrations mounted in South Sudan, mediators from the African Union High Level Implementation Panel for Sudan quietly issued a six-page document, publishing a list of the agreements so far, and what they still needed to settle.
It was remarkably short of dates and deadlines.
The two sides need to agree who owns the disputed Abyei area, mark out their border, move their forces outside a demilitarized border zone, work out how the south will pay the north to transport oil through northern pipelines, share out the waters of the Nile and prepare for a new currency in the south.
"Trying to work through outstanding disagreements, many of them already violent, will require difficult negotiations, political savvy, and carefully considered international engagement," wrote the International Crisis Group's Louise Arbour in the International Herald Tribune.
"At this point, the signs do not look particularly good."
Both sides also awoke to face their own problems.
In Khartoum, those include a loss of oil revenues, surging inflation, international isolation, insurgencies, infighting in the ruling National Congress Party and International Criminal Court (ICC) arrest warrants for Bashir and other officials.
Sudan's goodwill toward South Sudan may be short-lived if Washington fails to keep its promise to take Khartoum off its list of state sponsors of terrorism as a reward for recognising the south and other progress.
In his speech in Juba, Bashir urged the United States to lift sanctions. Instead, he was met with calls for more work.
"By continuing on the path of peace, the government of Sudan can redefine its relationship with the international community and secure a more prosperous future for its people," U.S. Secretary of State Hillary Clinton said in a statement.
If it feels betrayed by the United States, Bashir's administration, which once hosted Osama bin Laden, may turn its back on the West, strengthening ties with Palestinian group Hamas and with Iran.
In South Sudan, Juba will face its own internal battles against corruption, a mushrooming public sector it can ill afford, poverty, warring tribes, renegade militia leaders, raids by the vicious Ugandan rebel Lord's Resistance Army and an economy that produces next to nothing except oil.
Kiir acknowledged the challenges in his first speech as the new president, saying South Sudan was at the "tail end" of development scales. "From today onwards we shall have no excuse or scapegoats to blame," he told southerners.
Up to now, the actions of the leaders from the north and south have been governed by two main tactics. Neither encourages confidence for the coming talks or the stability of their nations which straddle the Arab world and Sub-Saharan Africa.
First there is the tactic of postponement.
Difficult settlements are put off, letting the cost of the disputes in terms of human lives and development mount while leaders get on with the day-by-day business of staying in power.
This has sometimes drawn in external players, African or the Western, but that has not guaranteed a solution in the past.
Sudan's eight-year Darfur conflict festers despite the presence of one of the world's biggest peacekeeping missions.
Second, there is the ploy of escalation, by politicians or the military, in a bid to draw concessions and then win credit by promising to calm a situation they ignited.
Analysts point to the north's seizure of Abyei weeks before the separation that was provoked by a southern attack.
The south won kudos for not being drawn further into conflict. The north got credit when it agreed to pull back, to make way for Ethiopian peacekeepers, days later.
Both tactics go a long way to explaining the overriding theme of internal Sudanese politics, at least in recent years. Plenty of drama with little political change. The 2005 deal was a rare exception but the main actors have stayed the same.
Bashir has been in power since 1989. Kiir became president of the autonomous south when his predecessor, John Garang, was killed in a helicopter crash in 2005. Before that he was a top officer in the southern rebel army.
For years, both sides traded accusations. That will likely continue in the months or years ahead, this time from across the border. Each may choose to continue scapegoating the other, swapping charges to explain the failures at home.
The people of the Republic of Sudan in the north and the new Republic of South Sudan may be hoping their leaders can come up with some new strategies.
(Additional reporting by Alex Dziadosz in Juba; Editing by Giles Elgood)