In his Senate office, on a shelf next to an autographed baseball, Sen. Rick Santorum keeps a framed photo of his son Gabriel Michael, the fourth of his seven children. Named for two archangels, Gabriel Michael was born prematurely, at 20 weeks, on Oct. 11, 1996, and lived two hours outside the womb. Upon their son's death, Rick and Karen Santorum opted not to bring his body to a funeral home. Instead, they bundled him in a blanket and drove him to Karen's parents' home in Pittsburgh. There, they spent several hours kissing and cuddling Gabriel with his three siblings,...