Following a constitutional conference at Lancaster House in London in February 1960, two national African parties were formed, the Kenya African National Union (KANU) and the Kenya African Democratic Union (KADU). The fundamental difference between the two parties resided in the fact that KANU tended to represent those persons and tribes that were most closely associated with an urban-oriented nationalism and sought a highly centralized political system for Kenya, while KADU represented the more rural and pastoral tribes, who feared a concentration of power by any central government. The political conflicts between these two parties tended to become identified with tribalism, since each party had a core group of tribes committed to it. In the national elections of May 1963, KANU won a majority of seats in both houses of parliament, and its leader, Jomo Kenyatta, assumed power. KADU dissolved itself voluntarily in 1964 and joined KANU.
Since 1964, KANU has dominated Kenyan politics. In March 1966, 30 KANU members of the House announced that they had formed an opposition party, later named the Kenya People's Union (KPU), led by Oginga Odinga, a Luo, who had resigned his post as vice president. By-elections for the 30 seats, held in June 1966, resulted in the KPU's retention of only 9. In July 1969, Tom Mboya, the minister of economic planning, was assassinated. His death touched off old animosities between his tribe, the Luo, and the politically dominant Kikuyu, to which Kenyatta belonged. The government used the pretext of the assassination to ban the KPU and jail Odinga and other opposition leaders. In the 1969 elections, Kenyatta—who ran unopposed—and the KANU slate were returned to power. All parliamentary candidates also were KANU members in 1974 and 1979; however, there were many more candidates than constituencies, and in all three elections a majority of incumbents were unseated.
Following reports that Odinga, who had been freed in 1971, was planning to form a new, Socialist-oriented party, the National Assembly on 9 June 1982 declared Kenya a one-party state. In the wake of the attempted coup that August, Odinga was again detained, and treason charges were brought against his son, Raila Odinga, dean of the engineering school of the University of Nairobi. The treason charges were later dropped, but Oginga Odinga remained under house arrest from November 1982 to October 1983. By that time, presidential and parliamentary elections had been held, with some 900 KANU members vying for the 158 elective seats.
A clandestine dissident group known as Mwakenya was founded in 1981. In 1986, 44 persons were being held in connection with this group, 37 of whom were convicted of sedition. Other underground opposition groups emerged in the 1980s and in 1987 many joined to form the United Movement for Democracy (UMOJA, Swahili for unity).
In December 1991, the Moi government decided to end KANU's monopoly on legal political activity. A grand coalition known as the Forum for the Restoration of Democracy (FORD) was formed, but, before the December 1992 election, it fragmented into two factions—FORD-Kenya, headed by Oginga Odinga and FORD-Asili, led by Kenneth Matiba. The Democratic Party of Kenya (DP) was headed by Mwai Kibaki and the Kenya National Congress (KNC) by Chilube wa Tsuma. Three other parties were active, even in the face of persecution by Moi's police. In particular, government prevented opposition MPs, domestic and international human rights figures, and journalists from entering the security zones of the Rift Valley, where the government conducted a policy of ethnic cleansing against the area's non-Kalenjin population. In 1993 alone, the KANU-led government arrested 36 of the 85 opposition MPs.
In the run-up to the scheduled 1997 elections, opposition parties made a brief attempt at unity with the formation in 1995 of the united National Democratic Alliance. Factional bickering, however, rendered it stillborn. Also in 1995, the Safina Party was founded by Richard Leakey, the world-renowned paleoanthropologist and former head of the Kenya Wildlife Service, a post for which he was handpicked by President Moi. Leakey intended to organize an umbrella opposition party, but Moi promptly banned Safina. By 1996, however, several opposition parties had tentatively acknowledged their support of Safina. By March 1997 there were 26 registered political parties, but only 10 won parliamentary seats in the 1997 elections judged as fairly credible.
In the run-up to the 27 December 2002 elections, the opposition led by Mwai Kibaki organized a grand electoral alliance, the National Rainbow Coalition (NARC). The seats won by party were as follows: NARC 125, KANU 64, FORD-P 14, other 7; ex-officio 2; seats appointed by the president: NARC 7, KANU 4, FORD-P 1.