IT WAS AN unlikely picture of harmony. On June 27th the foreign ministers of Rwanda and the Democratic Republic of the Congo stood smiling in the Oval Office next to Donald Trump, America’s president, who hailed the importance of the peace agreement they had just signed. “We’re here today to celebrate a glorious triumph,” said Mr Trump. “The violence and destruction comes to an end, and the entire region begins a new chapter of hope and opportunity, harmony, prosperity and peace.”