In 1994, a 9-year-old boy living in New Orleans' Central City neighborhood wrote a letter to President Bill Clinton, saying that he did not feel safe: "I want you to stop the killing in the city. People is dead and I think that somebody might kill me." Two days later, on Mother's Day, that boy, James Darby, was killed in a drive-by shooting. Darby's words rang out as loudly as ever on Friday evening in the neighborhood where he lived and died, when Mayor Mitch Landrieu told Darby's story to a large crowd in front of the home where another...