Accra, Ghana ? Opposition leader John Atta Mills was declared Ghana’s next president Saturday in a peaceful ballot that secured the West African nation’s place as a beacon of democracy on a volatile continent.

Ghana also is now one of the few countries in Africa to successfully transfer power twice from one legitimately elected leader to another. It made the transition to a mature democracy after experiencing years of coups in the 1970s and 1980s, and even survived the closest presidential vote in its history with Atta Mills’ win.

And significantly, in this election and the one in 2000, opposition leaders and not ruling party candidates won the presidency.

Opposition supporters thronged the streets after the announcement and jubilant drivers honked horns across the capital, Accra. Atta Mills told a pulsating crowd outside his campaign headquarters “the time has come to work together to build a better Ghana.”

“I assure Ghanaians that I will be president for all,” he declared.

Though buoyed by Ghana’s recent discovery of oil, the 64-year-old tax expert who takes charge Wednesday of the world’s No. 2 cocoa producer will have to struggle with the effects of a global economic downturn. The poor in Ghana already complain that wealth is not trickling down and Atta Mills has accused the government of corruption.

After the Dec. 7 election proved indecisive, Atta Mills won Sunday’s second round ballot by capturing a razor-thin victory with 50.23 percent of the vote to 49.77 percent for ruling party candidate Nana Akufo-Addo, according to the country’s Electoral Commission.

The historic ballot marked the third time Atta Mills ran for president — and was so close authorities had to rerun it Friday in one district that had a ballot shortage earlier.

Akufo-Addo conceded defeat and congratulated his rival, and the ruling party ended court filings questioning some districts’ voting results to promote national unity.

Peter Pham, an Africa expert at James Madison University in Virginia, was impressed by the election.

“(It’s) the first case in Africa I can think of where a country has seen two successive transfers of power from democratically elected incumbents to democratically elected successors,” he said.

That the transfers were between opposing governing powers “is an important indicator of the vibrancy of a country’s democracy and the maturity of its political institutions,” Pham added.

Some analysts had feared violence, noting that Kenya was also a model of stability in Africa until a similarly tight 2007 election unleashed weeks of tribal bloodshed.

Pham said former U.N. Secretary-General Kofi Annan — who helped broker peace in Kenya last year — flew home New Year’s Day and had been working behind the scenes to calm tensions in his native Ghana. President John Kufuor also called on both sides — including his own ruling party — to accept the results.

Atta Mills served as vice president under former coup leader Jerry Rawlings, who stepped down in 2001.