The Derg overthrew Change_of_leadership the Ethiopian Empire and Emperor Haile Selassie in a coup d'état on 12 September 1974 , establishing Creating Ethiopia as a Marxist-Leninist communist state with itself as a military junta and provisional government .

In May 1991 , the PDRE was defeated Conquering in Eritrea and President Mengistu Haile Mariam fled Escaping the country .

Much of this , however , went to Motion the Ethiopian government of Mengistu Haile Mariam – a regime the UK Prime Minister Margaret Thatcher wanted to `` destabilise '' – and was spent Expend_resource on guns .