The town of Abyei and its surrounds represent a vital historic link between northern and southern Sudan and an area of strategic importance.1 After fighting devastated the area during the First Sudanese Civil War (1955-1972), the people of Abyei were promised a referendum to decide whether the wanted to join the Southern Region or remain as part of the north. The referendum never took place, and the town once again became a battleground during the Second Civil War (1983-2005).2 During the peace process that culminated with the 2005 peace agreement, the US negotiating team sought to resolve the impasse over the territory of Abyei by proposing self-administration for the town until a referendum on its political future could be held alongside the plebiscite on independence for the Southern Region.3 The Abyei Protocol also included the creation of a boundary commission to define the borders of the contested territory prior to the referendum. When the commission presented its findings in 2008, they were flatly rejected by the Government of Sudan, leading to a rise in tensions that quickly escalated into renewed conflict. The situation worsened as the deadline for the referendum neared, with major clashes taking place in February and March 2011 before a major Sudanese offensive in April and May destroyed much of the town.4
In response to the destruction of the town, the UN Security Council unanimously approved Resolution 1990 on 27 June, authorising the deployment of a peacekeeping force to Abyei.5 This followed an agreement on ‘temporary arrangements’ between the belligerents negotiated a week earlier under the mediation of the South African president that requested a third party to monitor the ‘flashpoint’ of Abyei.6 With a mandate to use force to protect civilians and an initial mission strength of 4,200 military personnel (later expanded to 5,326), the relatively robust United Nations Interim Security Force for Abyei (UNISFA) deployed in an interpositionary location between the belligerents to prevent renewed clashes and stabilise the situation in and around the town. Following the referendum on South Sudanese independence, UNISFA was also tasked with monitoring the withdrawal of forces to their respective sides of the demilitarised border zone and helping to set up a monitoring mechanism along the newly established international boundary.7 The mission has succeeded in preventing renewed conflict in Abyei for a decade and continues operating at the time of writing.