Thabo Mbeki, South Africa’s former president, has arrived in Ivory Coast's commercial capital of Abidjan to mediate a dispute over who won the Nov. 28 election. Both the former President Laurent Gbagbo and his main challenger, Alassane Ouattara, claim victory and have had themselves sworn in.

These elections were supposed to bring peace to Ivory Coast after a bloody year-long civil war began in 2002. Back then, a rebellion of soldiers from the mostly Muslim north, calling themselves the New Forces, carved their own area of control as a result of a long-felt sense of discrimination by the political elite of the Christian-majority south.

But the Nov. 28 election results were tight, and government institutions have split sharply over who won. Electoral commission officials gave the election to Mr. Ouattara, the New-Forces-supported candidate, with a 54 percent victory. A high court judge, however, threw out hundreds of thousands of votes based on allegations of voter intimidation in the north and gave the victory to Gbagbo.

Now, with two men claiming victory, the country seems perched on the edge of new conflict, and Mr. Mbeki and fellow African Union mediator Dijibril Bassole, have arrived in Abidjan to see if a peaceful solution can be found.

The strongest leverage to encourage Gbagbo to abide by the official election results is ostracism by the US, the European Union, and the west African community of nations called ECOWAS, all of which have congratulated Ouattara on his victory and have called on Gbagbo to step aside. Yet as elections in Zimbabwe and other African nations show, when a leader loses elections but retains military backing, there is precious little that outsiders can do to push him out, unless they plan to intervene with military force of their own.

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