On 12 September 1974, the Derg overthrew the government of the Ethiopian Empire and Emperor Haile Selassie during nationwide mass protests, and three days later formally renamed itself the Provisional Military Administrative Council.

The abolition of feudalism, increased literacy, nationalization, and sweeping land reform including the resettlement and villagization from the Ethiopian Highlands became priorities.

[9] By the mid-1980s, Ethiopia was plagued by multiple issues, such as droughts, economic decline and increasing reliance on foreign aid, recovering from the Ogaden War, and the 1983–1985 famine from which the Derg itself estimated more than a million deaths during its time in power.

After the Ethiopian Revolution in February 1974, the first signal of any mass uprisings was the actions of the soldiers of the 4th Brigade of the 4th Army Division in Nagelle in southern Ethiopia.

The Coordinating Committee of the Armed Forces, Police and Territorial Army, known as the Derg, was officially announced on 28 June 1974 by a group of military officers.

This was done under the pretext of maintaining law and order, due to the powerlessness of the civilian government following widespread mutiny in the armed forces of Ethiopia earlier that year.

When a group of notables petitioned for the release of a number of government ministers and officials who were under arrest for corruption and other crimes, three days later the Derg was announced.

[14] The Derg, which originally consisted of soldiers at the capital, broadened its membership by including representatives from the 40 units of the Army, Air Force, Navy, Kebur Zabagna (Imperial Guard), Territorial Army and police: each unit was expected to send three representatives, who were supposed to be privates, NCOs and junior officers up to the rank of major.

But, Bahru Zewde notes that "in actual fact, their number was less than 110",[15] and Aregawi Berhe mentions two different sources which record 109 persons as being members of the Derg.

In July, the Derg obtained key concessions from emperor, Haile Selassie, which included the power to arrest not only military officers but government officials at every level.

Soon both former Prime Ministers Aklilu Habte-Wold and Endelkachew Makonnen, along with most of their cabinets, most regional governors, many senior military officers and officials of the Imperial court were imprisoned.

The Derg chose Lieutenant General Aman Andom, a popular military leader and a Sandhurst graduate,[19] to be its chairman and acting head-of-state.

However, General Aman Andom quarreled with the radical elements in the Derg over the issue of a new military offensive in Eritrea and their proposal to execute the high officials of Selassie's former government.

[20] Brigadier General Tafari Benti became the new Chairman of the Derg and the head of state, with Mengistu and Atnafu Abate as his two vice-chairmen, both with promotions to the rank of Lieutenant-Colonel.

In October 1978, the Derg announced the National Revolutionary Development Campaign to mobilize human and material resources to transform the economy, which led to a ten-year plan (1984/85 - 1993/94) to expand agricultural and industrial output, forecasting a 6.5% growth in GDP and a 3.6% rise in per capita income.

Many member of the ruling elite were deeply opposed to the idea of loosening control on the rebellious southern regions conquered under Menelik II.

[34] Hundreds of thousands fled economic misery, conscription and political repression and went to live in neighbouring countries and all over the Western world, creating, for the first time, an Ethiopian diaspora.

The 1984–1985 Tigray famine brought the political situation in Ethiopia to the attention of the world and inspired charitable drives in Western nations, notably by Oxfam and the Live Aid concerts of July 1985.

[35] A BBC investigation reported that Tigray People's Liberation Front rebels had used millions of dollars of aid money to buy arms; these accusations were later fully retracted by the corporation.

The geopolitical situation became unfavourable for the communist government in the late 1980s, with the Soviet Union retreating from the expansion of Communism under Mikhail Gorbachev's glasnost and perestroika.

Towards the end of January 1991, a coalition of rebel forces, the Ethiopian People's Revolutionary Democratic Front (EPRDF) captured Gondar (the ancient capital city), Bahir Dar and Dessie.

[38] In the words of the former US diplomat Paul B. Henze, "As his doom became imminent, Mengistu alternated between vowing resistance to the end and hinting that he might follow Emperor Tewodros II's example and commit suicide.

[42] In August 2018, Ethiopian former Prime Minister Hailemariam Desalegn while heading an African Union election observer mission in Harare met with Mengistu, and shared their photo on Facebook, which was quickly deleted as it proved so controversial and generally unpopular.

[43] In May 2022, Zimbabwe's Foreign Affairs Minister Ambassador Frederick Shava gave a clear sign that Harare would be prepared to extradite Mengistu in a reversal of Jokonya's policy.

In this respect, it closely resembles the definition of politicide outlined by Barbara Harff, who wrote in 1992 that no Communist country or governing body had been convicted of genocide.