South Sudan is in many ways an American creation, carved out of war-torn Sudan in a referendum largely orchestrated by the United States, its fragile institutions nurtured with billions of dollars in American aid. But a murky, vicious conflict there has left the Obama administration scrambling to prevent the unraveling of a major American achievement in Africa. With at least 1,000 people killed in fighting between government and rebel forces, and with disturbing reports of ethnically motivated atrocities by both sides, President Obama faces the real prospect that South Sudan could become Africa’s next failed state. On the first morning of his Hawaii visit, two weeks ago, Mr. Obama woke up to an urgent conference call with his national security team about the fighting in South Sudan, and efforts to evacuate American citizens. He has been briefed on it every day since, his aides said — a […]