Nairobi - Raila Odinga, Kenya's veteran opposition leader and one-time prime minister, has chosen to sit out Thursday's presidential election re-run, a move that may well end his dream of winning the nation's top job.The 72-year-old has been a mainstay of Kenyan politics since the 1980s, but despite four attempts has never won the presidency.Instead he seems to have inherited the political misfortune of his father, Jaramogi Oginga Odinga, who led the opposition for three decades but never the country.For this year's election, held in August, Odinga led a coalition called the National Super Alliance (NASA), overcoming traditional opposition divisions in what he saw as a surefire plan to defeat incumbent President Uhuru Kenyatta, 55, and his ruling Jubilee Party.When Kenyatta won Odinga cried foul and took his complaints to the Supreme Court, where a shock ruling overturning the result handed him a rare political victory.'Criminal enterprise'However Odinga dug his heels in over reforms to the electoral commission, and pulled out of the race with two weeks to go, insisting it would not be free and fair. "All indications are that the election scheduled for October 26 will be worse than the previous one," Odinga said as he announced his withdrawal.Odinga called the election commission a "criminal enterprise" and said he would not "participate in an illegality".Kenyatta vs. Odinga has been a dynastic rivalry between two families that have dominated Kenyan politics in the independence era. A generation ago, Jaramogi Odinga lost out to Jomo Kenyatta, Kenya's first post-independence leader.Lifelong presidential hopes thwarted Born into political royalty, a member of Kenya's western Luo tribe, Odinga entered parliament in 1992 during the rule of president Daniel arap Moi. He had spent much of the previous decade in prison or in exile during the struggle for democracy.He ran unsuccessfully for the presidency in 1997, 2007 and 2013, claiming to have been cheated of victory in the last two votes, as well as this year's. Many observers agree with Odinga's view that the 2007 election was deeply flawed.That result triggered widespread politically motivated tribal violence that left more than 1,100 dead.To stop the killings, international mediators forced a deal that saw the incumbent, Mwai Kibaki, continue as president, while Odinga took the specially created position of prime minister in a power-sharing government.He held the post until 2013 when he ran for president, losing to Kenyatta by a very narrow margin -- and losing his court challenge of the result.Tribal resentment Odinga once again claimed fraud after August's vote, but this time the Supreme Court ruled in his favour, annulling the presidential election due to "irregularities and illegalities".A decade on, the violence of 2007 still casts a shadow over Kenya's political landscape and tribal resentment endures.Odinga's backers among the Luos believe they are being denied political power by a cabal of Kikuyu elites currently led by Kenyatta.Odinga argues that a fair election would result in his victory, and his supporters believe him.He says Kenyatta is attempting "to overthrow our new constitutional order" and impose a dictatorship reminiscent of the Moi regime that Odinga struggled against.A polarising politician While his supporters consider Odinga a much-needed social reformer, for his detractors he is a rabble-rousing populist unafraid to play the tribal card.He is renowned as a firebrand speaker capable of galvanising a crowd with his oratory. But Odinga also has a reputation for being stubborn and sometimes short-tempered.For some observers, he has lost some of his crowd-pleasing skills, which some attribute to ill health and advancing years.With his speech notes in hand he often stumbles and labours over his words -- especially in English. Speaking off-the-cuff in his native Swahili however, he retains the ability to inspire.Raised an Anglican, he later converted to evangelicalism. In 2009, he was baptised in a Nairobi swimming pool by a self-proclaimed prophet. The Bible crept into Odinga's campaign this year with his repeated promise to lead his followers to Canaan, the mythical "promised land".Inequality He studied engineering in communist former East Germany and named his eldest son Fidel, who died in 2015, after the Cuban revolutionary.However observers say the "socialist" and "communist" labels he was given were more an attempt to discredit him by the Moi regime than an accurate reflection of his leanings.After returning to Kenya in 1970 Odinga set up as a businessman before following his father into politics.Nowadays he describes himself as a social democrat who wants to fight inequality.Married, Odinga has three surviving children: Rosemary, Raila Junior and Winnie.