Kenya African National Union nonetheless decided to remove all provisions of a federal nature from the constitution. Kenya became independent on December 12, 1963, and the next year became a republic within the Commonwealth. Jomo Kenyatta, head of the Kenya African National Union, became Kenya's first president. KADU dissolved itself voluntarily in 1964 and joined KANU after a strong lobbying by Tom Mboya. A small but significant leftist opposition party, the Kenya People's Union (KPU), was formed in 1966, led by Jaramogi Oginga Odinga, a former vice president and Luo elder. The KPU was banned and its leader detained after political unrest related to
Jomo Kenyatta by members of smaller ethnic groups like the Kalenjin and Masai. In May 1960, KANU nominated Kenyatta as its President, although the government vetoed it, insisting that he had been an instigator of the Mau Mau. KANU then declared that it would refuse to take part in any government unless Kenyatta was freed. KANU campaigned on the issue of Kenyatta's detainment in the February 1961 election, where it gained a majority of votes. KANU nevertheless refused to form a government, which was instead created through a KADU-led coalition of smaller parties. Kenyatta had kept abreast of these developments, although refused