South Sudan's President Salva Kiir, who fought as a rebel chief in one of Africa's longest civil wars, has confronted those two old and deadly enemies of development - poverty and corruption - in his first year as head of the world's newest state.
The guerrilla fighter turned president, who likes to wear wide-brimmed cowboy hats, has also faced persisting hostility from South Sudan's arch-foe to the north, Sudan, from whom it wrested independence last year after a secession vote that followed the end in 2005 of more than two decades of civil war.
The two neighbours in what was once Africa's biggest nation, straddling the fault line between the largely Muslim, Arabic-speaking north and black Africa to the south, came close to plunging back into war in April when they clashed over unresolved borders and the oil on which they both depend.
Kiir, seen as a no-nonsense army man, stunned the world when he sent troops to occupy the disputed Heglig oil zone, alleging self-defence against what he said were repeated attacks by the Sudanese army. A threat of sanctions by the U.N. Security Council forced both sides back to the negotiating table.
"Good fences make good neighbours," Kiir defiantly told South Sudan's parliament in June, proposing international arbitration of the border dispute. He insisted his landlocked country would not allow itself to be dominated by its more developed northern neighbour, which offers a gateway to the sea.
"I reject the proposition that the best way to peace with Sudan is through dependence on Sudan. No nation can prosper by surrendering control of its economy to another," he said.
Accusing Khartoum of "stealing" South Sudanese crude flowing through northern pipelines, Kiir's ruling Sudan Peoples' Liberation Movement (SPLM) shut down southern oil output from January, badly straining the economies of the two Sudans.
But Kiir, a committed Catholic with a reputation as a conciliator, also knows - and South Sudan's Western donors never tire of reminding him - that a good relationship with Sudan is the best guarantee for his country to be able to build a secure, prosperous, self-sufficient future for its 8.26 million people.
"The time for peace has come. We will stop at nothing short of a lasting peace between our two countries," he told parliament in a June 11 speech.
CREDIBILITY ON THE LINE
While other members of the southern elite boast academic credentials obtained in the West, Kiir won his main leadership credentials on the battlefield. He joined the south's first insurgency (1955-1972) at 17 and later became a major in the Sudanese intelligence services.
He constantly reminds his ministers and the South Sudanese people of the huge development challenges facing their newborn state, which has only about 100 km (60 miles) of paved road and health and education levels among the lowest in the world.
"Building a nation will take our lifetimes," he says, adding South Sudan must also bury tribal enmities that still erupt into cattle raids and bloodletting, the most recent only months ago.
Kiir has shown awareness too of the corrosive threat of corruption and inequality to his emerging nation, where walled private mansions and gleaming SUVs owned by a wealthy few contrast sharply with the humble mud-and-thatch homes and daily struggle to survive that is the lot of most South Sudanese.
In a letter sent in May to 75 current and former officials, Kiir estimated $4 billion had been "stolen" from public coffers and urged those responsible to return it.
"We fought for freedom, justice and equality," the president wrote, adding: "Many people in South Sudan are suffering and yet some government officials simply care about themselves. The credibility of our government is on the line".
Despite experts' warnings that the oil shutdown could cause economic collapse, Kiir is asking his long-suffering people to tighten their belts and rein in their expectations while his SPLM government implements austerity measures.
South Sudan is counting on foreign loans and aid from friendly states to keep on its toddler's feet until planned alternative pipelines can be built in 2-3 years to carry the south's crude to Kenya or Ethiopia, instead of through Sudan.
But the president says he wants to wean his people off the foreign aid handouts that have kept millions of South Sudanese from starving to death during decades of civil conflict.
"Let us not become addicted to free things ... people have learned how to be fed and not to feed themselves," he says.
"FORGIVE, BUT NOT FORGET"
Kiir, one of the founders of the SPLM who took over as its leader after the 2005 death in a helicopter crash of the charismatic John Garang, has repeatedly said he does not want to go back to war with Sudan. Before this month's clashes, Sudan's President Omar Hassan al-Bashir made similar statements.
It is clear that years of conflict between South Sudanese, who are mostly Christian or follow traditional religions, and the government, military and militias of the largely Muslim and Arabic-speaking north have left deep scars.
"We have been bombed, maimed, enslaved and treated worse than refugees in our own country, but we have to forgive, although we will not forget," Kiir said at the moment of independence on July 9 last year.
Kiir and Bashir had been due to meet in Juba on April 3 before border clashes scotched the meeting. They now plan to hold a meeting on the sidelines of an African Union (AU) summit in Addis Ababa this week, officials say,
When Kiir first stepped up as the leader of the then semi- autonomous south in 2005, many compared him unfavourably with his firebrand predecessor, the civil war hero Garang.
But Kiir, who rarely gives interviews, has concentrated on keeping his fragmented territory united. He has repeatedly offered amnesties to renegade militia leaders in the south and made progress in fighting rebels.
Kiir has been good at bringing old foes into the SPLM and the southern army. But worries remain about the ability of his party to accept rivals who insist on staying outside the fold.
His quiet approach and lack of polarising rhetoric are seen as his main strengths in governing a landlocked territory handicapped by tribal divisions, severe poverty, unstable neighbours and huge supplies of privately held weapons.
Thousands of people have died inside South Sudan in recent years in tribal clashes. The south says northern-backed militias provoked the violence. Khartoum denies the accusation.
Kiir is a member of the country's largest tribe, the Dinka, which largely controls the army and government, to the dismay of smaller tribes.
North and South Sudan's armies are also still facing off in flashpoints along their ill-defined shared border - including in Southern Kordofan, South Blue Nile and the contested Abyei area.
Kiir says he wants to turn South Sudan into "a land of promise - not a land of conflict, fragility and disaster".
But as he told an audience earlier this year: "We are starting from zero and starting with very little".
(Writing by Pascal Fletcher, editing by Diana Abdallah)