A long-shot candidate for the Iowa senate has released a commercial in which he promotes term limits for senators and also threatens to shoot the balls off a "sexual predator" who killed his sister. Bob Quast, unsurprisingly, is a supporter of gun rights. "If you are the sexual predator and sociopath who murdered my sister Lynette and you come to my front door to do harm to my girls, I'm going to use my Glock - to blow your balls off," he says, smiling. Quast's sister, Lynnette Craft, was killed in June 1999, by her husband, the ABC affiliate reported....