Ben Carson is not stupid, and anyone who says he is can be ignored in serious political discussions. But a man who spends his life reaching the summit of the medical profession obviously hasn't had a lot of time to learn the details of government policy. Every presidential candidate faces a learning curve; one who has no history in politics, such as Carson, faces a steeper climb. Duane Clarridge, chief of the CIA's Latin American division from 1981 to 1987 and an advisor to Carson, caused a major kerfuffle this week when he told the New York Times that,...