In 2011, after two decades climbing the ranks of Niger's army, Abdourahamane Tiani was handed one of the military's most prized appointments: the head of an elite unit set up to protect the president. Last week, Tiani, a general, used his position and manpower to do the opposite. He imprisoned President Mohamed Bazoum in the presidential palace and appeared on state television on Friday to declare himself head of state, confirming the seventh military coup in West and Central Africa in three years.