The 1972 invasion of Uganda was an armed attempt by Ugandan insurgents, supported by Tanzania, to overthrow the regime of Idi Amin. Under the orders of former Ugandan President Milton Obote, insurgents launched an invasion of southern Uganda with limited Tanzanian support in September 1972. The rebel force mostly consisted of the "People's Army" whose forces were mainly loyal to Obote, but also included guerillas led by Yoweri Museveni. The operation was hampered by problems from the start, as a planned rebel commando raid had to be aborted, Amin was warned of the impending invasion, and the rebels lacked numbers, training, and equipment. Regardless, the militants occupied a few towns in southern Uganda at the invasion's start. However, no major popular uprising erupted as Obote had hoped.
Without mass civilian support and outnumbered as well as outgunned, the rebels were mostly defeated by Amin's loyalists within hours. Most insurgents were killed or captured, while the rest fled in disarray back to Tanzania. Reinforced by allied Libyan and PLO troops, the Ugandan security forces launched operations to hunt down and destroy rebel stragglers, while initiating political purges against suspected Obote supporters. Meanwhile, Amin ordered his air force to retaliate by bombing Tanzania, prompting the latter to mobilize its army along the border. Before the conflict could escalate into a full war between Uganda and Tanzania, the two countries agreed to a ceasefire under Somali mediation, and subsequently ratified a treaty in Mogadishu to defuse tensions. Despite this, the conflict greatly worsened the already poor relations between Uganda and Tanzania, and ultimately contributed to the Uganda–Tanzania War.
Background
In 1971, a military coup overthrew the President of Uganda, Milton Obote. Colonel Idi Amin installed himself as new Ugandan President and ruled the country under a repressive dictatorship. However, this takeover was initially welcomed by many Ugandans, as Obote had become deeply unpopular in sections of the country's population and Amin presented himself as reformer. He freed several opposition figures who had been imprisoned under Obote, including Shaban Opolot, Grace Ibingira, and Benedicto Kiwanuka. The coup resulted in a deterioration of relations with neighbouring Tanzania, as Tanzanian President Julius Nyerere withheld diplomatic recognition of the new government and offered asylum to Obote and his supporters. After the coup, Amin launched purges of his enemies, and empowered his own followers to consolidate his regime. The country's military, officially known as Uganda Army (UA), was most affected by this development. Much of its leadership was killed or expelled, while members of ethnic and religious groups supportive of Amin were recruited and promoted en masse. A large number of soldiers and opposition figures targeted by the purges consequently fled into exile. They set up training camps and organized militant groups in Sudan and Tanzania. Sudanese President Jaafar Nimeiry opposed Amin due to his support for Sudanese Anyanya rebels, while Tanzanian President Nyerere had close ties with Obote and had supported his socialist orientation.
As a result, relations between Uganda and Tanzania became increasingly tense. Nyerere frequently denounced Amin's regime, and Amin made repeated threats to invade Tanzania. The situation was further complicated due to a border dispute, as Uganda claimed that the Kagera Salient—a stretch of land between the official border and the Kagera River to the south, should be placed under its jurisdiction, maintaining that the river made for a more logical border. The border had originally been negotiated by British and German colonial officials before World War I. In addition to the Kagera Salient, Amin also harbored hopes of acquiring a corridor to the Indian Ocean. Accordingly, he contemplated plans of conquering Tanzania's north, including the harbor town of Tanga. Following an armed clash between soldiers along the countries' common border a few months after the coup, Amin issued rules of engagement which clarified that the Uganda Army was only allowed to attack Tanzania in retaliation or if he gave orders to do so. Regardless, his political stance remained highly aggressive.