Mr. Ban is in Addis Ababa, Ethiopia, this weekend for the African Union (AU) Summit, a gathering of the continent's 54 nations, to discuss daunting challenges including the growing threat of Boko Haram. At the Summit's closing today, African leaders pledged to join forces to fight the terror group, which has in recent weeks attacked villages in Cameroon, displacing thousands to neighboring countries and sparking fears that its insurgency was expanding beyond Nigeria.