In 1992 Kenya had the first multi-party elections of the post-Kenyatta era. And in that election Moi won with 36.6% of the vote. Kenneth Matiba came second with 25.7% of the vote and bitterly contested the result. Matiba maintains that he won the election.
In the National Assembly, KANU had 100 seats against Ford-Asili's 31. Matiba's petition was thrown out because he had not personally signed it. He was physically incapacitated and had given his wife power of attorney to sign.
In 1997 the country voted and Moi won again. This time he got 40.4% against his closest challenger Mwai Kibaki's 30.89. Kibaki contested the result and his petition was thrown out on grounds that he had not personally served Moi.
He had printed the notice of petition in the Kenya Gazette. This was also the first time Raila Odinga ran for president - he came 3rd.
Importantly, Raila did not contest the result or claim that he won. Kibaki did. Meanwhile, Matiba boycotted the election on the grounds that he had won on 1992 and should thus be president.
In 2002 Kenya had arguably the most credible election it has ever held. And Mwai Kibaki won the election with 61.3% of the vote against Uhuru Kenyatta's 30.2%. No one contested the result, on account of the election being truly free and fair.
Raila Odinga did not run in the election, or challenge the result. So by 2002, the country had already seen 2 presidential election petitions, and 2 people claiming their victory was stolen, and importantly...none of them was Raila.
In 2007 Kenya had an election that was incident-free at the close of voting. An exit poll by the IRI (released years later) indicated that Raila Odinga won the election.
This agreed with ALL major opinion polls in the lead-up to the vote that showed Raila with a consistent lead over the incumbent Mwai Kibaki.
The catastrophic mismanagement and fraud within the vote tallying process was so severe that the ECK chairman disowned his own announcement. Violence broke out, ethnic tensions were inflamed and tore through the thin veneer of nationalism that held the country together like steam tears though the skin on boiling milk.
No objective observer endorsed the result, and many nations held back from congratulating Kibaki. There is an abundance of evidence from many diverse sources, including a recent article by a former official at the american embassy that indicate the election was deliberately rigged to prevent a Raila presidency.
This election was many steps backward after the success of 2002, and resulted in a coalition government. It is important to note that Raila did not call for violence, and in fact most of the fighting occured in the Rift Valley over a long-simmering issue of land. It is also important to note that all evidence suggests Raila did indeed win the election.
In 2013 the grand coalition came to an end, and an election was held. There was a persistent claim then that Raila Odinga never accepts defeat. Yet up to that point, he had only challenged one result, that of 2007 and much of the political class, citizenry and international community likewise challenged it.
So it was not Raila challenging a result in isolation, but rather a majority of people pointing out electoral fraud that almost tore the nation apart, and left it very divided. This election was largely incident-free at the close of voting.
Uhuru Kenyatta won the election with 50.07% of the vote, against Raila Odinga's 43.7%. On the face of it, the population accepted the result.
Raila Odinga filed his first presidential petition, claiming the election process was so severely compromised that the results could not have legal standing. In his petition Raila did not claim that he won the election, he simply claimed that the process was marred with enough irregularities to bring the result into question.
The petition's main body of evidence was dismissed on a technicality, and the Supreme Court-sanctioned audit of a sample of the results from polling station showing clear discrepancies to the advantage of Uhuru Kenyatta and to the detriment of Raila Odinga was inexplicably disregarded. The Supreme Court ruling was criticized by the International Commission of Jurists and various lawyers of repute.
Amid the petition process, public sentiment began to turn as blunder after blunder of the IEBC was revealed. Later, analysis of opinion polls showed that all presidential candidates in 2013 scored within their margin of error except for Uhuru, who beat his upper limit by a whooping 6%.
This is at best statistically improbable and at worst, cause for suspicion. There is sufficient evidence to show that both Jubilee and CORD were unable to reach 50% of the vote.
So there was perhaps some manipulation to achieve that result and avoid a runoff. Analysis by various credible sources, including exit polls show strong evidence that 2013 was going to go to a runoff, which all credible polls had pointed to a CORD win, since it was unlikely that Mudavadi's Amani would team up with Jubilee over CORD in the second round.
In conclusion, petitions were present before Raila ever contested the presidency. And there are two instances before him of candidates having claims of their victory being stolen. Finally, Raila has only ever contested the result in two elections, and in both of them there is an abundance of evidence that there was indeed fraud specifically to his detriment.
Matiba contested an election result bitterly, Kibaki did so too. Why is Raila handled differently yet of the three, his claims have a lot more evidence?