LONDON – Even the worst of African situations can be turned around. In Liberia it has been done in two years. The descent during the 1980s and 90s was precipitous, fast and deadly. A quarter of a million people were killed by rival militias, hundreds of thousands driven across borders into refugee camps, one president tortured to death and the macabre event recorded on video, young adolescent boys dressed up in wigs and terrified the populace with random killings and, not least, the country was systematically looted almost clean by its warlord/president Charles Taylor, who became rich on the export of timber, iron ore and alluvial diamonds from neighbouring Sierra Leone. Two years ago I was here at the war’s end. Nigerian and Ghanaian peacekeeping troops lined the road from the airport, backs to the road, eyes scanning the jungle for movement. The roads were sandbagged with checkpoints, the telephone...