The decision, due by Thursday, will end months of legal wrangling that has gripped the cocoa, gold and oil-exporting nation, one of Africa?s brightest economic growth prospects that has built a reputation for political stability.
Mahama won the December election with 50.7 percent of the vote and the opposition New Patriotic Party (NPP) launched a Supreme Court challenge, alleging fraud ranging from inflated tallies to the participation of unregistered voters.
The court?s nine-member panel can either validate Mahama?s win or order a re-run. Few expect violence either way.
?It will be a 7-2 (split) decision, or at worse 6-3 in favor of Mahama,? said Seth Gyekye, a political analyst at the Accra-based Futures think-tank.
Gyekye said evidence provided by the NPP party suggested the need for better training for election workers rather than a reversal of the result.
Ghana is home to one of Africa?s fastest growing economies and is expected to see 8 percent economic growth in 2013.
However, the need to hold another vote would be a blow to efforts to control its budget deficit, which ballooned to 12.1 percent during the 2012 election year, nearly twice the target.
Mahama took over as president last year when incumbent John Atta Mills died in office. The smooth transition reinforced Ghana?s reputation for political maturity in a region better known for its coups and violent post-election crises.
Voting in the 2012 poll was fraught with delays after hundreds of newly-introduced electronic fingerprint readers failed.
The non-partisan Coalition of Domestic Election Observers (CODEO), which had more than 4,000 people across the country, said the vote had been generally free and fair.
Margaret Boateng, a lawyer and human rights advocate, said she believed the evidence presented in court left no other option but to re-run the vote.
However, a senior lawyer who has followed the case but asked not to be named due to the sensitivity of the matter, said the opposition argument had most probably failed to convince the court.
?The status quo is likely to remain because the opposition only proved their case to some extent, but not enough to reverse last year?s declaration by the electoral commission,? he said.
Experts say calls for radical election reforms are inevitable.
Ghana?s police force has been readied to deal with trouble, but few anticipate problems on the scale of the crisis that gripped neighboring Ivory Coast, where a contested 2010 election led to post-election violence that killed 3,000.
Both Mahama and Nana Akufo-Addo pledged to accept the ruling and have asked their followers to do same. (REUTERS)