Political Struggles Within the GovernmentFollowing the establishment of his supremacy through the elimination of Tafari Banti, Mengistu declared himself Derg chairman in February 1977 and set about consolidating his power. However, several internal and external threats prevented Mengistu from doing this. Various insurgent groups posed the most serious threat to the Derg. The EPRP challenged the Derg's control of the revolution itself by agitating for a broad-based democratic government run by civilians, not by the military. In February 1977, the EPRP initiated terrorist attacks--known as the White Terror-- against Derg members and their supporters. This violence immediately claimed at least eight Derg members, plus numerous Derg supporters, and soon provoked a government counteraction--the Red Terror. During the Red Terror, which lasted until late 1978, government security forces systematically hunted down and killed suspected EPRP members and their supporters, especially students. Mengistu and the Derg eventually won this latest struggle for control of the Ethiopian revolution, at a cost to the EPRP of thousands of its members and supporters imprisoned, dead, or missing.
Also slated for destruction was MEISON, proscribed in mid1978 . In coordination with the government, MEISON had organized the kebeles and the peasant associations but had begun to act independently, thus threatening Derg dominance of local governments throughout the country. In response to the political vacuum that would be left as a result of the purging of MEISON, the Derg in 1978 promoted the union of several existing Marxist-Leninist organizations into a single umbrella group, the Union of Ethiopian MarxistLeninist Organizations (whose Amharic acronym was EMALEDEH). The new organization's duty was similar to that of MEISON-- promoting control of Ethiopian socialism and obtaining support for government policies through various political activities. The creation of EMALEDEH symbolized the victory of the Derg in finally consolidating power after having overcome these challenges to its control of the Ethiopian revolution.