A woman washes clothes in the Protection of Civilians site at the U.N. Mission in South Sudan in Malakal, South Sudan, on July 9, 2016. The site housed more than 32,000 displaced people at the time. (Jane Hahn/For The Washington Post)

THE FACT that the humanitarian disaster in South Sudan is man-made offers little consolation to the victims, but suggests that it might be reversed. This was once a fertile and oil-rich land; it is now convulsed by violence and hunger. Some 4 million people, a third of the population, are displaced internally or refugees abroad. Responsibility for this catastrophe rests on the shoulders of two men who led South Sudan to independence in 2011 and then squandered their legacy on war and enriching themselves.

In a recent interview with The Post, one of them, President Salva Kiir, was defiant. He did not accept any blame for the ruinous conflict with his rival and former first vice president, Riek Machar. Wearing the cowboy hat he received as a gift from President George W. Bush, Mr. Kiir declared, "I did not do anything that can make me regret." Asked whether his troops have made any mistakes, he responded, "I don't remember." He deflected a question about the role of his soldiers in violence by claiming that their uniforms were being stolen by Mr. Machar's men. Then he went on a rant about shootings in the United States.

Mr. Kiir is now in the driver's seat. Mr. Machar is in South Africa, although the remnants of his army still fight. The core problem for all those who have ambitions to save South Sudan is how to help its suffering people while forcing Mr. Kiir out of the way. For years, efforts have been made to get Mr. Kiir to agree to a sustainable peace, hold accountable those responsible for war crimes and build a functioning state. Talk doesn't work. Sanctions seem to bother him little. Peace agreements and various cease-fire arrangements have been reached and tossed away like tissue paper. An arms embargo failed to get off the ground in the U.N. Security Council.

On a recent visit, the U.S. Agency for International Development administrator, Mark Green, found Mr. Kiir in denial, disputing every concern he raised. Mr. Green announced that the U.S. administration would be carrying out a policy review, and President Trump asked U.S. Ambassador to the United Nations Nikki Haley to visit Mr. Kiir this month. In remarks at the Security Council in September, she declared that "this is the last chance" at salvaging a peace for South Sudan.

As warring groups splinter, it may be hard to ever put South Sudan back together. But the Trump administration does have a chance at a fresh start. Ms. Haley might consider reaching out to a younger generation of more technocratic leaders who are fed up with the failures of their elders. The administration should also press Egypt, Uganda and Ukraine to stop the flow of arms to South Sudan. The United States cannot forsake a people caught in the grip of misery; it must begin to look beyond the men who made this awful mess, including Mr. Kiir.