An even bigger challenge, she found, is promoting the Black professional community in San Francisco — a city where the African-American population has been steadily decreasing since 1970. Today, only one in 20 San Francisco residents is Black. Enter the Coalition of Black Excellence, the nonprofit Johnson is driving herself. A political science major at the University of Virginia, Johnson’s study-abroad experience in South Africa piqued her interest in foreign policy and international law. At the University of Pennsylvania Law School she found that litigating came naturally. But as Johnson got...