Nuer fighters in Upper Nile, South Sudan. Hopes for South Sudan’s future soared when it became a nation, but now diplomats are scrambling to make sense of how things went so wrong. Nuer fighters in Upper Nile, South Sudan. Hopes for South Sudan’s future soared when it became a nation, but now diplomats are scrambling to make sense of how things went so wrong.

After half a century of civil war, South Sudan declared independence from Sudan, in 2011. Two years later, the world’s youngest country erupted in its own civil war. In 2015, the combatants signed a peace agreement, but then the scales of power were tipped, and the government struck out against the opposing side. Now some are warning of genocide.

In December, President Obama lamented that his Administration hadn’t done more to address the crisis. His subordinates were torn over how to handle it; unfortunately, the National Security Council, which prevailed over the State Department, may have prolonged the carnage.

Hopes for South Sudan’s future soared when it became a nation, but now diplomats are scrambling to make sense of what went wrong. Some blame greed. As the new nation’s oil wells generated billions in revenue, a chaotic scramble for cash ensued. The rudimentary banking system couldn’t even handle credit cards, and government transactions were conducted using cardboard boxes filled with currency notes. Grandmothers and even four-year-old children were placed on the Army’s payroll. Some four billion dollars went astray.

In her harrowing memoir, “South Sudan: The Untold Story from Independence to Civil War,” Hilde Johnson, the former chief of the United Nations mission to South Sudan, suggests another factor. The nation’s political leaders, all war veterans, lacked the basic diplomatic skill of solving routine political problems through negotiation. Had so much money not been at stake, these leaders might have been able to settle their differences without bloodshed, but competition over riches, combined with the impatience with dialogue that Johnson describes, made the meltdown almost inevitable.

Early on, many observers noted the lacklustre performance of South Sudan’s President Salva Kiir, a mysterious, taciturn strongman. Short-tempered and fond of alcohol, Kiir was slow to make decisions and even slower to implement them. In 2013, Kiir’s smooth-talking, efficient Vice-President, Riek Machar, declared his intention to run in elections scheduled for 2015.

Neither Kiir nor Machar is an angel; both have been accused of war crimes. But when Machar made his Presidential ambitions known Kiir bristled, and diplomats urged Machar to wait until the elections scheduled for 2020. Machar ignored this advice, and, with his allies, continued to criticize Kiir in public. The issues between the two had little to do with tribal divisions at first; some of those who agreed with Machar belonged to Kiir’s tribe, the Dinka, while some of those loyal to Kiir belonged to Machar’s tribe, the Nuer. However, as political tensions mounted, so did lingering grudges over past atrocities committed by one ethnic community against another that had never been redressed through reparations or any form of justice.

On December 15, 2013, Kiir, fearing a coup, ordered Dinka members of his Presidential Guard to disarm their Nuer counterparts. The coup plot was almost certainly a false alarm, but Kiir’s soldiers nevertheless went house to house, killing thousands of defenseless Nuer men, women, and children. Those who tried to escape were herded into grass-thatched houses that were doused with kerosene and set alight. Some were forced to drink each other’s blood. A rebel movement allied to Machar reacted by mowing down thousands of others, mostly Dinka, decapitating some of the bodies. Women and children had their limbs cut off and were raped with various objects.

Much of South Sudan’s regular Army deserted to Machar’s side, but within days they were stopped in their tracks by the sudden intervention of the Army of Uganda, South Sudan’s southern neighbor. For the next two years, thousands of Ugandan troops propped up Kiir and fought Machar. Uganda’s President Yoweri Museveni had long seen Kiir as a protégé and Machar as a rival. The stalemate greatly prolonged the war, killing tens of thousands of people and causing over a million to flee their homes. Many South Sudanese saw Uganda’s presence as a foreign occupation, and many Ugandans, who have suffered mightily under thirty years of Museveni’s despotic and corrupt rule, wondered what their army, dispatched without parliamentary approval, was doing there.

A year after the carnage began, Samantha Power, the American Ambassador to the U.N., and her French and British counterparts urged the Security Council to impose sanctions, including an arms embargo, against Kiir’s government. This could have cut back Kiir’s Ugandan supply lines and forced both sides into more serious negotiations sooner. Secretary of State John Kerry supported the move, as did dozens of humanitarian groups. There were signs that Russia and China might have been persuaded to support it as well. But all were overruled by Susan Rice, the head of Obama’s National Security Council, who has a history of going easy on Uganda’s Museveni. According to Foreign Policy magazine, Rice maintained that Machar was also guilty of war crimes, and that, in any case, Uganda would ignore an embargo. U.N. Security Council meetings were held, and aid to the victims was authorized, but the killing continued.

Finally, in August, 2015, the two factions in South Sudan signed a peace deal. Under its terms, the capital city of Juba would be demilitarized, Kiir’s troops would be confined to their barracks, and Machar would serve as Kiir’s Vice-President once again.

Everyone knew that asking the two men to share power was a risky proposition. They hated each other. Nevertheless, both had strong, well-armed followings, and, since both refused to step down, a detente based on a balance of military power seemed the only way to secure a ceasefire. But, as the months wore on, Kiir failed to hold up his side of the bargain. His troops were not demobilized, and Machar, fearing for his life if he returned to Juba, stayed away. Under intense international pressure, especially from the U.S., Machar finally returned to Juba in April, 2016. As he had feared, he was entering a trap. On July 8th, as Machar and Kiir were meeting at the Presidential Palace, Kiir’s troops attacked Machar’s bodyguards. At least three hundred people, including civilians, were killed in the ensuing mayhem. Troops marauding through the city also raped aid workers and murdered foreign peacekeepers and refugees who were sheltering in a U.N. compound. Machar, under intense ground attacks and aerial bombardment, sustained severe injuries and spent forty days in flight through the forests of Congo.

Rather than sanctioning Kiir for destroying the peace process, U.S. Special Envoy to South Sudan Donald Booth told a congressional hearing that the State Department considered it unwise for Machar to return to Juba. Isolating Machar upset the balance of power that had protected his supporters from Kiir’s ruthless army, which went on yet another rampage last fall, on the pretext that rebels were rustling cattle. Machar furiously declared war on Kiir’s government, and is now in South Africa, under surveillance by South African security, while Kiir’s men continue to “eliminate” pockets of resistance inside the country. Anyone suspected of loyalty to Machar is in severe danger; many innocent men, women, and children are again being massacred.

In November, the U.S. finally began pushing for sanctions against Kiir in the Security Council, but by then it was too late to persuade Russia and China to go along. In her 2002 book, “A Problem from Hell,” Ambassador Power called for a global responsibility to protect people everywhere from crimes against humanity. Now that she’s about to retire, perhaps she’ll explain why this is easier said than done, but here’s some advice for the Trump Administration: genocide doesn’t happen overnight. It begins with small injustices, power grabs, and callous dismissals of the rule of law. Even more important than the responsibility to protect is the responsibility to prevent, using negotiation, diplomacy, and sanctions long before the killing starts. By then, it is far, far too late.