The president of South Sudan, Salva Kiir, often wears a black cowboy hat that President George W. Bush gave him. The two men met multiple times at the White House back when Kiir was vice president of Sudan. The United States, along with Britain and Norway ,helped negotiate the peace agreement that formally spun off South Sudan into its own country in 2011. 

And while President Bush has gone, Kiir's hat remains a potent symbol of America's involvement with the world's newest country. Fighting between the South Sudanese government and opposition forces kicked off in 2013, with Kiir accusing rivals of plotting a coup against him. Since, Vice President Riek Machar, now the leader of the opposition, and Kiir, have gone through torturous negotiations to reconcile their two factions. 

But in the meantime, the fighting has taken a devastating toll on South Sudan — the United Nations estimates that 50,000 people have died in the last two years, and another 2.2 million have been displaced. 

Famine also endangers at least 30,000 people and 4 million more face severe hunger. The U.N. released a report last week accusing the government forces of devastating atrocities, such as using rape as a weapon of war. The report also claims that the government has burned people alive, intentionally suffocated individuals in containers, or mutilated bodies by cutting them into pieces.

"Given the breadth and depth of the allegations, their gravity, consistency and recurrence and the similarities in their modus operandi, it concludes there are reasonable grounds to believe the violations may amount to war crimes and/or crimes against humanity," the report says.

Eric Reeves, a Sudan researcher and analyst, and author of "Compromising with Evil: An Archival History of Greater Sudan, 2007 - 2012," says that U.S. influence in the area has deteriorated in the past decade.

He warns that the fighting since the end of 2013 has pitted ethnic groups against each other, making stability and reconciliation even more difficult.