[allAfrica] Washington, DC -- In an open letter, 47 former high-ranking U.S. officials -- many of whom served as American ambassadors in Africa - take strong issues with a New York Times column last week by Brett Stephens entitled Susan Rice Was a Diplomatic Disaster. The signatories include two Republicans who succeeded Rice as Assistant Secretary of State for Africa -- Walter Kansteiner and Jendayi Frazer, as well as the two former ambassadors who held that post during the Obama administration -- Johnnie Carson and Lin