South Sudan's 2018 Revitalized Agreement on the Resolution of the Conflict in South Sudan, known as the R-ARCSS, was signed under significant international pressure after five years of civil war that killed hundreds of thousands of people and produced one of the largest displacement crises in Africa. The agreement brought Riek Machar back to Juba as First Vice President. It established a transitional government with power-sharing arrangements across South Sudan's fragmented political landscape. It set a timeline for elections and for the unification of armed forces that had spent years fighting each other.
In 2026, most of those benchmarks remain unmet. Elections have been delayed three times. The unified army that the agreement mandated has not been formed in any meaningful operational sense. Machar spent years under effective house arrest in Pretoria before returning to South Sudan in late 2023 under conditions that have remained opaque. The transitional government has extended its own mandate repeatedly rather than submitting to an electoral process that no party to the agreement appears confident it can win on its own terms. The R-ARCSS is technically still in force, but the conditions that would make it a functioning peace have not materialised.
This is not a new observation. The fragility of South Sudan's peace process has been documented by UN experts, by the Reconstituted Joint Monitoring and Evaluation Commission, and by the civil society organisations that have watched each deadline pass without enforcement. What is changing in 2026 is the combination of pressures, political, economic, and regional, that are making the already thin foundations of the agreement thinner still.
What the 2018 agreement was actually built on
To understand why the R-ARCSS is fraying, it is necessary to understand what it was built on in the first place. The agreement was not the product of a military stalemate in which neither side could advance. Nor was it the product of a genuine political reconciliation between the Kiir and Machar factions. It was the product of exhaustion, international pressure, and the calculation by both principal actors that a power-sharing arrangement, even an imperfect one, was preferable to continued fighting that was producing diminishing returns for everyone.
That calculation was always fragile because it rested on mutual tolerance rather than mutual interest. Salva Kiir and Riek Machar have been in political conflict since at least 2013, when Kiir dismissed Machar as vice president and the political dispute rapidly militarised along ethnic lines, with Dinka communities broadly aligned with Kiir and Nuer communities broadly aligned with Machar. The two civil wars that followed, from 2013 to 2015 and then from 2016 to 2018 after the first peace agreement collapsed, embedded ethnic mobilisation into the conflict in ways that the R-ARCSS addressed at the elite political level without addressing at the community level.
The agreement also left unresolved the question of oil revenue distribution, which is the material foundation of South Sudan's political economy. Oil accounts for the overwhelming majority of government revenue, and control over the institutions that manage oil revenue is inseparable from control over the patronage networks that hold political coalitions together. The transitional government has managed this by distributing positions across factional lines without creating transparent oversight mechanisms, which means that oil revenues continue to flow to political actors who have an interest in maintaining the current arrangement rather than submitting it to electoral accountability.
The elections question and why it cannot be resolved
Elections in South Sudan have been delayed so many times that the deadlines themselves have become a ritual rather than a commitment. The most recent extension pushed the electoral timeline to late 2026, a date that most observers consider unlikely to be met given the absence of a completed voter registration process, a functioning electoral commission, and a security environment in which voting in many parts of the country would be impossible.
The reasons for delay are genuine in some respects. Voter registration in a country where displacement has moved millions of people from their home areas is technically and logistically complex. The security sector reform that was supposed to produce a unified national army capable of guaranteeing electoral security has not happened. The political parties that would contest an election have not been able to operate freely across the country in areas controlled by armed groups aligned with specific factions.
But the technical obstacles, while real, are not the primary reason elections keep being delayed. The primary reason is that no major political actor in South Sudan currently believes that elections would produce an outcome they could accept. Kiir's SPLM controls the state and has the most to lose from an open electoral process. Machar's SPLM-IO has the most to gain but lacks the organisational reach and resources to be confident of winning. Smaller parties and armed groups that are part of the transitional arrangements have their own reasons for preferring the current distribution of positions to a competitive process that would require them to demonstrate a popular mandate they may not have.
This is the structural logic of many post-conflict transitions: the peace agreement creates a power-sharing arrangement that all parties have an interest in maintaining because the alternative, submitting to an election, is too uncertain. The result is a political stasis that is stable in a narrow sense but generates no legitimacy and no accountability, while the underlying grievances that produced the conflict remain unaddressed.
The Machar factor in 2026
Riek Machar's return to Juba from Pretoria in late 2023 was presented as evidence that the peace process was still functional. The reality has been more ambiguous. Machar has resumed his position as First Vice President but has operated under significant constraints, with his freedom of movement limited, his political organisation fragmented after years of his absence, and his relationship with Kiir no warmer than it was before the 2013 conflict.
The SPLM-IO, the political and armed wing that mobilised around Machar during the civil wars, is not a unified organisation in 2026. Multiple commanders who fought under the SPLM-IO banner have since made separate arrangements with the Juba government, some integrating into national security structures, others operating with varying degrees of autonomy in their home areas. This fragmentation means that Machar's ability to deliver the SPLM-IO as a coherent political force is limited, which in turn limits his negotiating leverage within the transitional arrangement.
The risk associated with the Machar factor is not that he will deliberately attempt to destabilise the agreement. It is that the constraints on his position, combined with the failure to implement the security sector reforms that were supposed to give his faction a real stake in the national army, mean that armed groups nominally loyal to the SPLM-IO operate in a grey zone where they have no strong institutional incentive to maintain the peace. Local conflicts over cattle, land, and resource access in Jonglei, Unity, and Upper Nile states are a recurring source of violence that the transitional government has not developed the capacity to mediate or contain.
Sudan's war as a complicating factor
South Sudan's peace process was already fragile before the SAF-RSF war began in Sudan in April 2023. The war has added complications that have received less attention than they deserve.
South Sudan's oil exports travel through Sudan via a pipeline to Port Sudan for export. The war in Sudan has periodically disrupted pipeline operations and created uncertainty about South Sudan's ability to export oil consistently. Oil revenue is the basis of the transitional government's fiscal position and its ability to fund the patronage networks that hold the political arrangement together. Disrupted oil exports mean disrupted revenue, which creates pressure on the political settlements that depend on that revenue being available for distribution.
Sudan has also sent refugees south into South Sudan's Upper Nile and Unity states, adding to an already severe humanitarian situation in areas that were among the most affected by South Sudan's own civil wars. The South Sudanese government has neither the resources nor the institutional capacity to manage a significant additional refugee influx, and the communities receiving refugees are themselves food insecure and politically fragile.
The regional guarantors of South Sudan's peace process, Kenya, Uganda, and Ethiopia through their roles in IGAD, are all managing their own domestic challenges in 2026. Ethiopia is dealing with the aftermath of the Tigray war and ongoing Amhara regional conflict. Kenya is managing economic stress and political pressure from the Gen Z protest movement's aftermath. Uganda's Museveni government, which has historically been the most willing to use its military relationship with Kiir as leverage in the peace process, has its own succession concerns. The bandwidth available for sustained engagement with South Sudan's peace process is limited.
What a second collapse would look like
It is worth being specific about what a breakdown of the R-ARCSS would mean, because the phrase "return to civil war" can obscure what that actually looks like at the community level.
The 2013 to 2018 civil war was not a conventional military conflict between two armies. It was a set of overlapping local conflicts, ethnic mobilisations, and communal violence episodes that the Kiir-Machar political conflict ignited but that then generated their own internal logic in specific areas. In Jonglei, fighting between Lou Nuer, Murle, and Dinka Bor communities operated on dynamics that had little to do with the political dispute at the top of the government. In Unity state, fighting over oil-producing areas mixed political conflict with resource competition. In Western Equatoria, armed groups that had initially aligned with neither principal actor began attacking civilian populations for local reasons.
A second collapse would not be identical to the first, because the political and military landscape has changed significantly since 2013. But it would likely follow the same pattern: a triggering political conflict between elite actors that rapidly becomes a permission structure for local armed groups to act on local grievances, with ethnic framing providing the mobilisation mechanism. The displacement would be massive. The humanitarian situation, already severe, would deteriorate further. The regional spillover into Uganda, Kenya, and Ethiopia would accelerate.
None of this is inevitable. The R-ARCSS has held for eight years, imperfectly and incompletely, but it has prevented a return to the full-scale fighting of 2016. The question for 2026 is whether the combination of delayed elections, constrained economic conditions, reduced regional attention, and unresolved security sector reform has eroded the foundations of that holding pattern to the point where a triggering event, a political dispute, an assassination, a local conflict that escalates, could send it into collapse. The honest answer is that it is closer to that point than it has been at any time since the agreement was signed.