South Sudan

Peace has been elusive in South Sudan, which, with U.S. support, became the world's newest country in 2011. The civil war that erupted there in late 2013 featured widespread sexual violence, mass killings, and other atrocities. It displaced over a third of the population and fueled Africa's largest refugee crisis for a decade. An estimated 400,000 people died as a result of the war before the most recent peace deal was signed in 2018. Whether that ended the war is debated. Conflict has continued to plague the country, and the situation is deteriorating in 2025 as hostilities rise.

South Sudan ranks as one of the world's poorest and most fragile states, the most corrupt, and one of the least free. Its security forces have "mutilated, tortured, beat, and harassed political opponents, journalists, and human rights activists," per the State Department, and targeted government critics outside the country. President Salva Kiir's government has repeatedly delayed what would be the first elections since independence. Kiir's regime arrested First Vice President Riek Machar, his leading rival and co-signatory on the 2018 peace deal, in March, accusing him of inciting rebellion.

The United States, which facilitated the 2005 peace deal that enabled South Sudan's independence from Sudan, has been the country's largest aid donor and the penholder on the issue in the UN Security Council. Congressional interest, driven historically by humanitarian and human rights concerns, has shaped U.S. policy toward what is now South Sudan for decades. The U.S. Embassy continues to press for implementation of the peace deal and has called for Machar's release and a return to dialogue.

Humanitarian Situation

South Sudan faces a severe humanitarian crisis that has grown over the past decade: per UN estimates, 9.3 million people (three-quarters of the population) need aid in 2025; 7.7 million face acute food insecurity. Over 1.8 million are internally displaced; 2.3 million are refugees in neighboring countries. Widespread flooding since 2019 has added to displacement and food insecurity. South Sudan ranks as one of the countries most vulnerable to natural hazards and climate change impacts and as one of the most dangerous countries for aid workers. Sudan overtook South Sudan as Africa's largest refugee crisis in 2024; South Sudan has faced an influx of over a million refugees and returnees from Sudan, straining communities and aid operations.

Competing donor priorities and increasing costs have led to humanitarian funding gaps since 2020, forcing aid agencies to reduce assistance amid rising needs. U.S. assistance has routinely comprised over half of all humanitarian funding for South Sudan. The Trump Administration's foreign aid pause and cuts, which have drawn congressional debate, have reportedly disrupted some life-saving programs; Save the Children has cited them as a factor in several deaths. The State Department says that the United States "continues to provide critical, life-saving assistance in South Sudan."

Figure 1. South Sudan Key Facts

Source: CRS map. Figures from CIA and IMF reference databases.

Background and Context

South Sudan's independence followed a vote for secession from Sudan after almost 40 years of rebellion. Decades of war had inhibited the development of human capital, basic infrastructure, and formal institutions, fueling humanitarian needs that persisted after independence, despite rich natural resources, including oil fields that once generated 75% of Sudan's oil production. As former rebels, South Sudan's leaders had little experience governing, and corruption and conflict slowed post-war recovery and development.

The civil war in Sudan that led to South Sudan's secession is often characterized as a north-south struggle, but fighting among southern rebel commanders nearly derailed the south's bid for self-determination. Leaders in the Sudan People's Liberation Movement/Army (SPLM/ SPLA) vying for power mobilized their supporters along ethnic lines, and Sudan's government fueled SPLM divisions by financing breakaway factions (a tactic Kiir has adopted). The rebel factions reconciled in the early 2000s, helping the SPLM form a united front in peace talks with Sudan's government, culminating in the 2005 Comprehensive Peace Agreement (CPA). Under the CPA, Sudan remained unified for a six-year interim period before southerners voted on separation.

After the CPA, the SPLM became the south's ruling party. With the death of longtime SPLM leader John Garang just months after the CPA signing, the south lost its leading advocate for a united Sudan, and in 2011, over 98% of its voters chose secession. The new country was awash in small arms, and grievances fueled local rebellions and intercommunal violence. The SPLA, which became South Sudan's army, responded with violent, ethnically targeted disarmament campaigns. Maneuvering ahead of the first post-independence elections planned for 2015 added to these dynamics. A 2013 cabinet reshuffle, in which Kiir dismissed his vice president, Riek Machar, formalized a major fissure in the SPLM. Tensions rose as Machar and other SPLM leaders accused Kiir of becoming increasingly dictatorial, and erupted in December 2013, as the party convened to choose its presidential candidate for the polls.

Civil War

The political dispute that triggered the 2013 crisis was not based on ethnicity, but overlapped with ethnic and political grievances, spurring targeted ethnic killings and clashes in the capital and then beyond. What began as a fight in the presidential guard split the military, largely along ethnic lines. Attacks targeting Machar's Nuer ethnic group (the country's second largest) were followed by revenge attacks against Kiir's ethnic group, the Dinka (the largest group). Machar and some senior Nuer military leaders subsequently declared a rebellion. The ensuing war pitted government forces and ethnic militia loyal to Kiir against those aligned with Machar. Uganda provided initial military support to Kiir's regime and reportedly facilitated its arms imports.

As the violence spread, over 200,000 people sought refuge at UN peacekeeping bases, which became Protection of Civilians (POC) sites. Some experts assess that the decision by the UN Mission in South Sudan (UNMISS) to open the bases to civilians may have saved tens of thousands of lives. One POC site, in Upper Nile state, remains, providing shelter to over 40,000 civilians facing ongoing insecurity.

The warring parties, who became known as the SPLM-IG (In Government; led by Kiir) and SPLM-IO (In Opposition; led by Machar), broke multiple ceasefires before, under threat of sanctions, they signed the Agreement on the Resolution of the Conflict in the Republic of South Sudan (ARCSS) in 2015. Kiir called the deal an attack on South Sudan's sovereignty and both parties delayed implementing it until early 2016, when they formed a unity government, with Machar returning as one of two vice presidents. The detente did not last long. A series of confrontations between the parties' forces in Juba in July 2016 reignited the war, and Machar, pursued by Kiir's forces, fled the country.

Seeking to maintain the appearance of a unity government, Kiir replaced Machar with the latter's former deputy and sacked SPLM-IO cabinet members and legislators loyal to Machar, who led the main SPLM-IO faction from exile. The rebellion spread and fractured, with defections from both sides and new groups emerging. The war moved into the southern Equatoria region, fueling a new insurgency, spurring a refugee surge, and affecting key trade routes. Inter- and intracommunal tensions rose across the country.

After years of debate, the UN Security Council authorized an arms embargo on South Sudan in 2018. Soon after, Kiir, Machar, and several other political leaders signed a new deal, the Revitalized ARCSS (R-ARCSS). Other groups rejected the deal, saying it failed to address the war's root causes. An expanded government was eventually formed in 2020, with Machar becoming one of five vice presidents.

The R-ARCSS stemmed direct clashes between the military and IO, but it did not bring peace. Kiir has encouraged defections from the splintered SPLM-IO and used ethnic militia to wage campaigns in opposition-dominated states, fueling counterattacks from community defense groups like the Nuer White Army. Amid succession speculation, the violence has escalated. The regime's unilateral replacement of opposition officials and detention of Machar and other senior IO leaders violate the R-ARCSS. Airstrikes, with Ugandan support, on Nuer villages, attacks on cantoned IO forces, and remarks by regime officials categorizing Nuer areas as "friendly" or "hostile" fuel the country's fracture.

Justice and Accountability

In 2015, an African Union (AU) Commission of Inquiry reported grounds to believe that war crimes and crimes against humanity had been committed in the civil war. It recommended the creation of an AU-backed hybrid court to ensure accountability. The UN Commission on Human Rights in South Sudan has since reported other violations it says may amount to war crimes, crimes against humanity, and ethnic cleansing. The commission reported in early 2025 that it continues to see "the same patterns of gross violations in the same places, often implicating the same public and military offices," and assessed that "pervasive impunity" fuels violence and instability in the country. Kiir committed to a hybrid court in 2015 but has not acted on it.

The Economy: Oil, Gold, and Corruption

South Sudan has Africa's fifth-largest proven oil reserves. The oil sector, which lacks transparency and is rife with corruption, dominates its economy. Oil accounted for 90% of state revenue and 95% of exports before one of the two pipelines carrying its oil through Sudan for export was damaged in early 2024, cutting exports and related revenue by almost 70%. The government stopped paying salaries to civil servants and security forces for a year. The pipeline has been repaired, but salary arrears have not been cleared.

Some experts describe South Sudan as a kleptocracy. Power is centralized around Kiir, and beyond Juba, in the absence of a functioning state, informal checkpoints flourish, taxing trade and aid. The illicit trade of gold and timber is facilitated through neighboring countries, notably Uganda.

U.S. Policy and Foreign Assistance

South Sudan's civil war and U.S. concerns about corruption and gross human rights abuses have strained bilateral ties. Some Members of Congress, while expressing U.S. support for South Sudan's people, have pushed for accountability from its leaders and criticized support for "the status quo." The United States has designated 25 people and related companies under a South Sudan sanctions regime or Global Magnitsky sanctions. The first Trump Administration added 15 oil operators to the Commerce Department's Entity List, pushed for the UN arms embargo, and set a policy of visa restrictions for those undermining peace. The Biden Administration also imposed sanctions and visa restrictions, including for corruption and transnational repression, and issued a business advisory on risks for U.S. companies. The Trump Administration announced a visa ban for South Sudanese in April 2025 over a deportation dispute.

U.S. assistance, most of it humanitarian, has totaled over $700 million annually for a decade and routinely comprised over half of all humanitarian funding for the country. South Sudan is subject to aid restrictions in annual appropriations provisions and based on its use of child soldiers and limited efforts to eliminate human trafficking. Non-humanitarian aid has focused on the health sector, which is heavily reliant on donor support, as well as peacebuilding, civil society, and independent media. The Trump Administration has not published details on country-specific aid cuts, but reports suggest the suspension of U.S. funding shuttered some health clinics and nutrition programs. The U.S. Embassy reduced its presence in early 2025, citing security concerns.