The United States, which played a key role in South Sudan's independence and is the country's largest donor, declared itself a steadfast partner of the world's newest country in 2011. Two years later, in December 2013, South Sudan collapsed into civil war. An August 2015 peace agreement led to the much-delayed formation of a Transitional Government of National Unity in April 2016. That event, while a major step forward, began a dangerous new phase of reconciliation in which opposition leader Riek Machar returned to the capital, Juba, to assume the post of First Vice President alongside his former foe, President Salva Kiir.

On July 1, 2016, the International Crisis Group warned that implementation of the peace deal had stalled and a return to war could be imminent. In the week prior, fighting displaced 70,000 people in Wau, an area not significantly involved in the war. The two factions had made no effort toward demobilizing or integrating their forces. The peace deal sought to demilitarize Juba, requiring the government to redeploy most of its forces outside the city, with each side allowed only a small protective detail. Subsequent negotiations expanded the number of troops allowed by each side and made concessions on weaponry. As a result, when the opposition returned to Juba, they did so armed, with cease-fire monitors unable to verify the number of government troops in the city.

The uneasy truce between the factions has unraveled, with the situation deteriorating rapidly on July 10 and 11. A series of incidents involving Kiir and Machar's forces raised tensions in recent weeks, and in separate incidents on July 7, armed units clashed and a U.S. embassy convoy and a U.N. official were shot at in Juba, spurring the President and First Vice President to hold a press conference on Friday calling for calm. According to some reports, a shootout between their bodyguards took place outside the presidential compound before the event began, sparking clashes elsewhere in the city. Kiir and Machar ultimately held the press conference, reassuring the public that those responsible would be held accountable.

July 9, the country's fifth anniversary, was reportedly calm, but fighting broke out the following day. Government and opposition representatives met in an effort to stem the violence, suggesting that Kiir would issue a unilateral cease-fire and urging Machar to follow suit. The fighting continued for another 24 hours, raising questions of command and control on both sides. Kiir eventually ordered a cease-fire on the evening of July 11. Machar issued a similar order hours later, and the city has since quieted.

Reports suggest that hundreds were killed in the violence, much of which appears to have been between armed forces, although civilians were caught in the crossfire and, in some cases, possibly targeted. At least two Chinese peacekeepers were killed, and several Rwandan peacekeepers were wounded. Outside Juba, clashes were reported on July 11 in Torit, the capital of Eastern Equatoria state, where violence spurred hundreds to flee to a U.N. base, and in other locations in Central and Eastern Equatoria.

Civilian protection concerns are now high on the international community's agenda. The proximity of the main U.N. compound in Juba to both an army base and a cantonment site for opposition forces was a significant cause for concern during the fighting. The U.N. site sustained casualties and damage from heavy weapons fire. The site hosts U.N. staff and more than 35,000 civilians who have sought shelter with the United Nations—some 7,000 came in recent days, but most have sheltered with the United Nations since the onset of the war. The U.N. Mission in South Sudan (UNMISS) has had the daunting task, among other duties, of protecting almost 200,000 people seeking shelter during the war at peacekeeping bases, now known as Protection of Civilian (POC) sites, with 12,000 troops. (The total number sheltering at POC sites had declined to 160,000 until the fighting in Wau, which increased the number by almost 20,000.) Heavy fighting in downtown Juba also led hundreds to flee to the other U.N. base in the city, near the airport in a neighborhood where the U.S. embassy is located. On July 10, UNMISS called for South Sudan's leaders "to allow access to the United Nations to be able to patrol in order to reassure the civilian population." On July 12, it again called for movement restrictions to be lifted, suggesting that peacekeepers had been unable to patrol since the fighting began.

The Security Council discussed concerns about UNMISS's ability to protect civilians in June as it heard reports on deadly violence at a POC site in February. A confidential UNMISS contingency planning document in late 2015 apparently "noted that if large-scale violence broke out in Juba the mission would have difficulty protecting civilians, and would be engaged with protecting U.N. staff and its humanitarian partners."

The U.N. Security Council issued a unanimous statement after a July 10 emergency session calling for an end to the fighting, expressing "particular shock and outrage" at attacks on U.N. sites and stressing that such attacks may constitute war crimes. The statement expressed readiness to consider enlarging UNMISS and "encouraged States in the region to prepare to provide additional troops in the event the Council so decides," while stressing the need for UNMISS to "make full use of its authority to use all necessary means to protect civilians." The U.N. Secretary-General said the violence "made a mockery of commitments to peace" and called for an arms embargo and further targeted sanctions. The region's foreign ministers issued several demands of the parties on July 11, including an immediate cessation of violence and reopening of the airport and humanitarian corridors. The ministers have urged revision of UNMISS's mandate to allow a regional intervention force to secure Juba. The Security Council is scheduled to discuss these proposals today.

The State Department ordered the departure of non-emergency U.S. embassy personnel on July 10, and the U.S. military facilitated that departure on July 12; the embassy remains open. Hundreds of U.S. citizens are estimated to be in the country, many working with aid agencies. Those in Juba have been sheltering in private compounds, reliant on local security staff. Nearby fighting essentially closed the airport until July 12, when evacuation flights began. Ugandan forces, which by some accounts played a critical role in securing the Juba airport in 2013, reportedly have no plans to redeploy to Juba.

The United States has provided $275 million to date in humanitarian aid for South Sudan in FY2016 and almost $1.6 billion since the conflict began. Non-humanitarian aid focuses on mitigating conflict and fostering stability, delivering essential health and education services, improving food security, and supporting implementation of the peace agreement. U.S. assessed contributions to UNMISS were estimated at $342 million in FY2016.