Concrete walls with long shards of glass embedded along the top, brutal points glinting in the hazy yellow light of the Sahel, surrounded the American embassy compound. Similar defenses protected private homes in the few neighborhoods that boasted living trees and roads with some tarmac still intact. Those with any means walled themselves behind concrete and cut glass, the only entrance a metal gate guarded by men with semi-automatic rifles and chained dogs kept on the cruel side of hunger.   Once, two Marines in a LandCruiser drove us to the home of an American defense attaché to spend the night. It was meant to be a treat. Air conditioning. Eating with utensils instead of scooping with our right hands. A bath. A bed not tented by mosquito netting sprinkled with termites. No…