By Estelle Shirbon
LONDON, March 31 (Reuters) - The victory of opposition candidate Muhammadu Buhari in Nigeria's presidential election could mark a turning point towards genuine democracy for the country, improving the image and moral standing of Africa's troubled giant.
The defeat of President Goodluck Jonathan, whose People's Democratic Party (PDP) has run Africa's most populous nation since it returned to civilian rule in 1999, was the first time a Nigerian head of state lost power to an opposition challenger through the ballot box.
"It's not the result that we wanted but it's a good day for Nigeria if we show the world we can run a credible election," said a minister in Jonathan's government, who did not wish to be named because others in the PDP were angry about the result.
Jonathan telephoned Buhari on Tuesday to congratulate him on winning this weekend's election, a spokesman for Buhari's All Progressives Congress (APC) said.
Now Africa's biggest economy, Nigeria has nevertheless been held back by the legacy of three decades of army misrule: a mix of corruption, weak institutions, political, ethnic and religious violence, and a dearth of infrastructure.
Nigeria accounts for about one in six Africans and a fifth of African GDP, giving it huge potential influence on the continent and beyond, but instead for decades it has been a by-word for corruption and chaos.
It ranks 136th out of 174 on Transparency International's index of perceived corruption, a problem that affects Nigerian society from top to bottom and cannot be turned around overnight, even by the austere Buhari.
Nevertheless, a transfer of power from one political party to another, achieved through voting rather than violence, is a marked improvement on previous elections since 1999 which were widely believed to have been rigged in favor of the PDP.
"It will help reinforce perceptions across the continent that the old ways are much harder to get away with," said Antony Goldman, a business consultant with high-level contacts in Nigeria. He highlighted the role of voters armed with mobile phones and Internet connections in preventing vote-rigging.
While the challenge in turning Nigeria around is as daunting as ever, it would be a positive outcome if the ruling class no longer felt it could stay in power regardless of performance, analysts said.
"THEY HAVE TO DELIVER"
"Especially in Nigeria, given the history, the bad name it has, I think this will be a positive surprise," said Antoon de Klerk, a portfolio manager at Investec Asset Management who invests in African bonds and currencies.
"There's a greater degree of accountability. The fact that they can lose means they have to deliver."
Therein lies the challenge for Buhari, whose democratic credentials have yet to be fully tested. He first wrote his name in Nigerian history when, as a general, he ousted a civilian government in a 1983 coup. He was deposed two years later by another general.
Now, he faces a new set of problems, not least the Boko Haram Islamist insurgency in the North and the risk of unrest flaring up in the oil-producing Niger Delta when Jonathan, a son of the Delta, is no longer in power.
"There is a great deal of disaffection with the narrowness of the leadership choices and a worry over the military past and credentials of candidates," said Christopher Cramer, a professor at the School of Oriental and African Studies in London.
"Nigeria will only really garner greater international authority if it can show a much more effective political and security strategy for dealing with the multiple challenges the country faces, from Boko Haram in the North to the ongoing corruption, criminality, and conflict in the Niger Delta."
There is also the issue of Nigeria's finances, which have been badly hurt by a dramatic fall in global oil prices.
"If you're running an unsustainable set of macro-economic policies sooner or later, unless that changes, you're going to get into trouble," said Jan Dehn, head of research at Ashmore Group, an emerging markets investment manager.
"Nigeria has not concluded its adjustment to the fall in oil prices. The fact that the election now looks to be drawing to a close is very good because this will now free the government to be able to undertake that much-needed adjustment," he said.
Consultant Goldman said that even in opposition, the PDP had a role to play in turning Nigeria into a genuine democracy.
"To have a democracy you need not only to have credible elections and a choice," he said. "The PDP has enjoyed the trappings of power for 15 years. The challenge for it now is to prove itself to be effective in opposition." (editing by David Stamp)