The tiny East African country of Djibouti has learned how to make money off its location. On June 27, Djibouti will celebrate the 40th anniversary of its independence, and it has experienced profound change since it was called first French Somalia, then the French Territory of Afars and the Issas. After its independence from France, Djibouti grappled with internal ethnic cleavages and a volatile region. But the secret to Djibouti's continued global importance and its success in recent decades lies in its strategic position on the Bab el-Mandeb strait and its status as the lone entry and exit point for its dynamic neighbor, Ethiopia....