Thats not the whole truth ndugu
Here is a little recap just to refresh our memories:
By the time of his overthrow in April 1979, the government of President Idi Amin was believed to have been responsible for the murder of "at least 100,000 and possibly as many as half a million people." His eight-year regime was marked from the very beginning by repression and brutality. In the early period, the victims were primarily soldiers from the Acholi and Langi ethnic groups because they were assumed to be in favour of the reestablishment of the government of Milton Obote, whom Amin had overthrown in the January 1971 coup d'état. A number of massacres of Acholi and Langi occurred between 1971 and 1973, but in the ensuing years the lack of discipline of the army and other armed agents of the regime was such that by 1977 the violence "had become almost random." As AI was later to report, "the absence of restraint on killings of political opponents and criminal suspects led to many other civilians being seized and killed by members of the security forces for criminal motives or simply quite arbitrarily." In April 1978, Amin publicly denounced his own vice president and minister of defence, army chief-of-staff, and chief of police. Then, at the end of September and early in October, Amin was forced to suppress mutinies at a number of army bases. Loyal troops pursued some of the mutineering soldiers across the border into Tanzania. Some days later, Amin announced on Ugandan radio that Uganda was annexing the Kagera region of northwest Tanzania. President Julius Nyerere of Tanzania responded by declaring that Uganda's purported annexation of Tanzanian territory was "tantamount to an act of war."
Tanzania began a counterattack in mid-November. By early December, it had pushed the Ugandan forces back across the border into Uganda. In a number of public statements, Amin referred to a "Phase Two" of his operation to annex the Kagera region; and in mid-December Ugandan troops invaded Tanzania a second time. That attack was repulsed, but Ugandan forces once again attacked in January. Nyerere was later to claim that, at this point, a decision was made to pursue the Ugandan forces well into Uganda, back to the army bases at Masaka and Mbarra, and to destroy those bases but that no decision had been made to penetrate further into Uganda.
The rapid advance of the invading Tanzanian troops and Ugandan rebel forces alarmed Amin to the point where, on February 23, he called on "friendly countries in Africa, the Third World, Arabs, socialist countries and the PLO" for support. In an effort to prop up the regime, Libya's Colonel Muammar Ghaddafi sent Libyan troops to Uganda. In early March, the Nairobi Times reported that approximately 2,500 Libyan troops had arrived in Uganda. On March 13, Amin publicly announced that Palestinian forces had also joined the struggle on his side. Amin's use of foreign troops convinced Nyerere that Tanzania would not enjoy security unless Amin himself was overthrown. Tanzanian forces were ordered to penetrate deeper into Uganda. Kampala, the capital, fell on April 10, and Amin fled into exile, first to Libya and ultimately to Saudi Arabia.