Few Americans knew more or cared more about the Arab world. Raised in Idaho, Hooper, 40, fell in love with Arabic two decades ago. At the United Nations, he became well known for his energy and keen political judgment. “He had the most penetrating and powerful intellect I have ever encountered,” his former boss, U.N. Under Secretary-General Terje Roed-Larsen, said at a memorial service last month. Single and stretched thin, he still had time for family. In June he flew to California to squire his grandmother to her 70th high-school reunion.