In less than a quarter of an hour every day, life in Djibouti City all but comes to a standstill. It begins just after an Ethiopian Airlines flight lands at 1 p.m. at Djibouti-Ambouli International Airport, bringing the 11 to 12 tons of qat Djiboutians consume daily. Qat, a leaf harvested from the homonymic tree that grows widely in Ethiopia and Yemen, is used commonly in the Horn of Africa, in the southern part of the Arabian Peninsula, and more recently in the Somali expatriate community in London.

The United States ambassador to Kenya was frustrated. It was almost eight months after suicide bombers blew up part of a resort hotel at almost exactly the same time other terrorists tried to shoot down an Israeli airliner taking off from nearby Mombasa-Moi International Airport — yet no one had been convicted.

One dramatic act sets Ethiopia apart from the array of countries with poor human rights records that have become United States counterterrorism allies since the September 11, 2001, attacks: With U.S. backing, it invaded a neighboring country and overthrew a Taliban-like Islamist movement.