From the CIA World Factbook:

"The colonial boundaries created by Britain to delimit Uganda grouped together a wide range of ethnic groups with different political systems and cultures. These differences prevented the establishment of a working political community after independence was achieved in 1962. The dictatorial regime of Idi AMIN (1971-79) was responsible for the deaths of some 300,000 opponents; guerrilla war and human rights abuses under Milton OBOTE (1980-85) claimed at least another 100,000 lives. The rule of Yoweri MUSEVENI since 1986 has brought relative stability and economic growth to Uganda. During the 1990s, the government promulgated non-party presidential and legislative elections."