War in Somalia (2006–2009)

The Ethiopian invasion of Somalia, also known as the Ethiopian occupation of Somalia was an armed conflict lasting from mid-2006 to early 2009. It began when Ethiopian military forces, supported by the United States, invaded Somalia to depose the Islamic Courts Union (ICU) and install the Transitional Federal Government (TFG). The conflict evolved into a military occupation and a rapidly escalating anti-Ethiopian insurgency. By 2008, insurgents had recaptured the majority of territory lost by the ICU during the invasion. The conflict caused the second largest population displacement since 1991.

Ethiopian military involvement began in mid-2006 in response to the rise of the ICU, which operated as the de facto government in southern and central Somalia. To reinforce the weak, Ethiopian-backed TFG, troops from the Ethiopian National Defence Force (ENDF) began deploying into Somalia in June. Six months later, the combined ENDF/TFG coalition, alongside a covert US military contingent, launched a full-scale invasion aimed at regime change. The ICU's organizational structure disintegrated and ENDF/TFG forces entered Mogadishu in the last days of 2006.

In early 2007, an insurgency emerged centered on a loose coalition of ICU loyalists, volunteers, clan militias, and various Islamist factions, among which al-Shabaab eventually assumed a pivotal role. In the same period, the African Union (AU) established the AMISOM peacekeeping operation, sending thousands of troops to Somalia to bolster the besieged TFG and ENDF. The Alliance for the Re-liberation of Somalia (ARS), a political successor to the ICU, further incited the insurgents. Over the following two years, the ENDF, TFG, and AMISOM became entrenched in a protracted struggle against an escalating insurgency, leading to the displacement of nearly one million inhabitants from Mogadishu.

By the end of 2007, ENDF troops were bogged down in a multifront war with no prospect of victory. While Mogadishu witnessed fierce fighting, insurgents launched offensives across southern and central Somalia in late 2007 and 2008, regaining territory previously lost by the ICU. In 2008, al-Shabaab began taking control of significant tracts of southern Somalia, governing territory for the first time. Piracy off the coast of Somalia, previously suppressed by the ICU, proliferated greatly.

The Ethiopian military occupation continued to falter, and by autumn 2008, more than 80% of the territory the ICU lost during the invasion had been recaptured by the insurgency. The TFG remained weak and divided. By December 2008, the overwhelming majority of TFG security forces had deserted, and the TFG was only able to control parts of Mogadishu and the city of Baidoa. TFG President Abdullahi Yusuf resigned soon after, stating that he had lost control. The insurgency had effectively won.

At the end of 2008, the ARS was assimilated into the TFG in an attempt to halt the growing insurgency and form a representative government. During January 2009, former head of the ICU Sharif Ahmed was elected president. Declaring victory and claiming to have eradicated the 'Islamist threat', the ENDF withdrew from Mogadishu, ending the two-year occupation. Most territory lost by the ICU had been recovered by Islamist insurgents, including much of Mogadishu. Years into the present phase of the civil war, Ethiopia became re-involved and joined AMISOM in 2014 in order to counter the growth of al-Shabaab.