By Estelle Shirbon
ABUJA (Reuters) - A Nigerian tribunal upheld the 2007election of President Umaru Yar'Adua on Tuesday, rejectingchallenges from rivals who had demanded a re-run because theysaid the vote was massively rigged.
The two challengers immediately said they would appeal tothe Supreme Court, which could take several more months todeliver a final ruling.
The tribunal ruled that opposition candidate MuhammaduBuhari, Yar'Adua's main opponent, had failed to prove thatviolations of the electoral law were substantial enough toinvalidate the president's victory.
The five-judge tribunal also rejected a challenge broughtby former Vice-President Atiku Abubakar, who came third in theelection that local and international observers said was "notcredible" because of widespread fraud.
"Umaru Yar'Adua and Goodluck Jonathan remain the presidentand vice-president of the Federal Republic of Nigeria," saidJudge John Fabiyi, reaching the conclusion of a ruling thattook more than three hours to deliver.
Reacting to the ruling, Buhari told reporters outside thecourt: "For us, we have come to the semi-final. We areproceeding to the Supreme Court."
Abubakar's allies also said they would appeal.
Yar'Adua's office issued a statement welcoming the ruling.
Nigeria, Africa's most populous nation and the world'seighth-biggest exporter of crude oil, emerged nine years agofrom decades of army rule.
It has a long history of botched elections and militarycoups and many had feared that an annulment could havedestabilised the country.
STABILITY
"From a political stability perspective, this is likely tobe positive," said Razia Khan, regional head of research forAfrica at Standard Chartered Bank in London.
"We expect the decision to be positive for the performanceof Nigerian markets," she said.
Yar'Adua's victory was disputed from the moment it wasannounced and doubts over whether he would finish his four-yearterm have delayed policy-making and investment decisions.
Analysts said Yar'Adua would now be under pressure todeliver on key policies.
"The key is whether the greater political certaintytranslates into more effective government. There is not a lotthe government can point to after nine months in power," saidGraham Stock, Africa strategist at JP Morgan in London.
"Now there are no excuses, we will be looking for a robustdefence of the government's original budget plans, greaterclarity on the regulatory framework for private/publicpartnerships and investment plans for the state-owned oilcompany," he said.
The legal battle will now move to the Supreme Court, butthe odds will be heavily stacked in favour of Yar'Adua afterthe tribunal rejected every single one of the challengers'points.
Some commentators saw the simple fact that the challengewent through the courts as a positive development on acontinent where disputed elections can lead to violence, asKenya's December 27 vote has done.
But others think differently. Numerous civil societyactivists had called for the vote to be reversed, arguing thatthe polls were so badly flawed that they were a hollow parodyof democracy.
