Following its independence in 1956, the Sudan had suffered from numerous internal conflicts over political, ethnic, economic, and religious issues. In 1983, revolutionaries and separatists from the country's marginalized south launched an uprising against the government which was traditionally dominated by elites from the north. The Second Sudanese Civil War had begun, and fighting spread across southern, eastern and western Sudan. The most prominent southern rebel group was the "Sudan People's Liberation Army" (SPLA) under the leadership of John Garang. As the war escalated and spread, the SPLA grew increasingly powerful and overran much of southern Sudan. Despite these successes, the SPLA faced major internal and external opposition. Many southern Sudanese outright opposed the group for a variety of reasons, and instead sided with the government or set up rival insurgent movements. In addition, Garang's leadership style caused tensions within the SPLA. He was charismatic, and a capable military commander, but also brutal and autocratic, suppressing and even executing critics.
Two prominent SPLA commanders, Riek Machar and Lam Akol, attempted to overthrow Garang in an unsuccessful coup in 1991. The SPLA consequently split into warring factions, and the Sudanese government exploited this by employing a divide and rule strategy. It occasionally supported Machar's group (SPLA-United) so that it could fight against and weaken Garang's faction (SPLA-Mainstream). In the next decade, alliances and militias formed and broke up again, while warlords carved out their own domains. The Sudanese government increasingly focused on clearing areas in the south for oil extraction instead of winning the war, as it was in desperate need of cash. As time went on, oil money became crucial for the Sudanese war effort. One of the centers of oil production was Unity State, also known as Western Upper Nile. To secure the oil wells and pipelines and open land for oil extraction, the government often employed southern militias. These paramilitaries knew the terrain, were more expendable than Sudanese Armed Forces (SAF) units, and allowed the government to frame the civil war as anarchic tribal infighting to deflect criticism of its own governance.
Oil fields and infrastructure in Sudan and South Sudan
The most prominent pro-government paramilitary group of southern Sudan was the SSDF. The SSDF was an umbrella organization for several armed factions, including Machar's loyalists and the troops of warlords like ex-Anyanya II leader Paulino Matip Nhial. It proved to be unstable and affected by internal rivalries, and gradually broke apart. Different SSDF factions already fought each other in 1997 and 1998, and the government allowed it to happen as it mistrusted most of the SSDF anyway. The combat between the pro-government militias was fuelled by a desire of the warlords to control the oil-rich areas and thereby increase their revenue. Matip managed to oust Machar's followers and other rivals from the valuable region around Bentiu, drawing the latter's ire. At the same time, the regime intensified efforts to take full control of the Block 5A oilfields in Unity State. These were held by Machar's forces, and he protested that the oil fields should remain under his control. The government responded by launching a campaign to drive away civilians and Machar's troops from drilling locations in Block 5A such as Thar Jath. Spearheaded by the SAF, northern militias, and Matip's force, entire tracts of land were depopulated. In response, Machar's local loyalists under Tito Biel and Peter Par Jiek aligned with the SPLA and counterattacked. A chaotic and brutal campaign ensued, as the military and numerous militias fought over control of the oil fields.
In September 1999, most of Matip's militia revolted under Peter Gadet, as they were upset how the government was using local Nuer militias (like themselves) against other Nuer,[a] while excluding them from the oil revenues. This was a major setback for the government. Gadet was a highly competent commander, and quickly captured the arms depot at Makien military base. He subsequently unified his force with the militias of other regional warlords such as Biel and Par to form the "Upper Nile Provisional United Military Command Council". The rebel alliance proceeded to capture several important oil wells, and the towns of Buoth, Rier, and Tan near Bentiu.
The Upper Nile Provisional United Military Command Council broke apart after the return of Riek Machar
(pictured 2014) to southern Sudan.
The insurgents consequently agreed to split Unity State. Gadet and Par were assigned territories mostly in accordance to the ethnic groups which supported them: Gadet, an ethnic Bul Nuer, got Mayom and Wangkei (inhabited by Bul Nuer), while Par, a Dok Nuer, was granted Bentiu, Thar Jath, Leer, and Adok (territory of the Dok, Jikany, Jagei, and Leek Nuer). The "Upper Nile Provisional United Military Command Council" alliance was quite successful, and the united forces of Gadet and Par defeated the SAF and Matip's militia in several battles. This adversely affected government control over Unity State, and reduced local oil production. The situation changed once again in February 2000, when Machar openly broke with the government, fully left the SSDF, and founded the SPDF rebel group. This development resulted in new tensions among the insurgents of Unity State. Machar loyalists like Par and Biel joined the SPDF, while Gadet had officially sided with SPLA-Mainstream – Machar's declared enemy.[b] Limited clashes between Gadet and some Machar loyalists, though not between Gadet and Par, broke out soon after. Despite the tensions and opposing political alignments, cooperation mostly continued until the Sudanese government launched another major offensive in Unity State in April 2000. This offensive pushed the rebel alliance to the breaking point. Old rivalries came to the fore, fuelled by the government's divide and rule strategy.