In 2005, Kenyans rejected a plan to replace the 1963 independence constitution with a new one. As a result, the elections of 2007 took place following the procedure set by the old constitution. Kibaki was re-elected in highly contested elections marred by political and ethnic violence. The main opposition leader, Raila Odinga, claimed that the election results were rigged and that he was the rightfully elected president. In the ensuing violence, 1,500 people were killed and another 600,000 were internally displaced, making it the worst post-election violence in Kenya. To stop the death and displacement of people, Kibaki and Odinga agreed to work together, with the latter taking the position of a prime minister. This made Odinga the second prime minister of Kenya.