During the Second Sudanese Civil War, White Army fighters mainly from the Lou Nuer subtribe backed the breakaway SPLM/A faction led by Riek Machar, known as SPLA-Nasir, in attacks on the Dinka majority. They were partly responsible for the Bor massacre, in which at least 2000 people were killed in 1991. However, the fighters never formed long-term alliances with other factions in the war, acting for short-term benefit only. Among their most regular enemies were the Murle people, a rival tribe competing for land and cattle in the states of Jonglei and Upper Nile. During the war, though the term "White Army" could refer collectively to Nuer youth militants, there was rarely any functioning central authority for the disparate fighters, and a number of White Army factions based around different cattle camps operated autonomously or semi-autonomously of one another. The ranks of leadership had a reportedly high rate of turnover.
2000s
After the Comprehensive Peace Agreement of 2005 between the government of Sudan and the SPLM/A, which formed the Autonomous Government of Southern Sudan, the Nuer White Army lost its remaining coherence. By February 2006, Nuer elders interviewed by Small Arms Survey workers acknowledged they had little or no control over the armed youths and said the incidence of cattle theft and other miscreant behaviour on the youths' part was increasing. Riek Machar, the White Army's erstwhile wartime ally, announced the White Army would be disbanded amidst a SPLM/A disarmament campaign in the region. However, it was not until a major defeat in May 2006 near Motot, in Jonglei's Uror County, in which 113 White Army fighters were reportedly killed for the loss of a single Sudan People's Liberation Army soldier, that the fighters gave up their attempts at resistance, according to the Small Arms Survey. The news serviceIRIN reported that more than 1,000 Lou Nuer men and boys in Akobo County who had been part of the White Army voluntarily surrendered their weapons to authorities in July 2006.
2010s
In late December 2011, several months after South Sudan gained its independence, The Upper Nile Times reported that the Nuer White Army had reformed and had issued a threat on Christmas Day 2011 to "wipe out the entire Murle Tribe on the face of the earth as the only solution to guarantee long-term security of Nuer's cattle". The statement also declared the White Army's intention to fight the SPLA and the United Nations, which has a peacekeeping mission in the country. The declaration marked an escalation in the ongoing clashes between the SPLA, the Murle, and the Lou Nuer in Jonglei and Upper Nile, which began when armed Murle fighters under the influence of George Athor's South Sudan Democratic Movement launched a cattle raid against the Lou Nuer in Jonglei state. UNMISS responded by deploying peacekeepers to Pibor town and urging both the Murle and Lou Nuer to lay down their arms.