In 1848, Horace Mann, the godfather of the modern public school system, wrote that education is “the great equalizer of the conditions of men—the balance wheel of the social machinery.” But is that still true today? Reuters followed two high school students in Massasschusetts, home to the nation’s top public school system, and found evidence that our schools are becoming the opposite of what Mann envisioned: another source of division between the wealthy and everyone else.