Philadelphia Mayor Michael Nutter became the latest politician to speak out against the National Rifle Association’s proposal to put armed guards in every American school to dissuade incidents such as the horrific shooting massacre at Sandy Hook Elementary School in Newtown, Conn., joining New York City Mayor Michael Bloomberg in his Mayors Against Illegal Guns initiative. Nutter, a staunch advocate of gun control, called the idea proposed by NRA CEO Wayne LaPierre a “dumb-ass idea.” Nutter, a Democrat, was speaking about a gunman who shot and killed two firefighters in Webster, N.Y., Monday after they arrived at a house fire....