(CNSNews.com) - Efforts to discredit radio news commentator Rush Limbaugh escalated this week with a new radio ad campaign hammering Limbaugh for comments he made about the abuse of Iraqi inmates at the Abu Ghraib prison. Still unresolved, meanwhile, is the Palm Beach County, Fla., prosecutor's investigation of Limbaugh for possible "doctor shopping" in connection with Limbaugh's admitted former addiction to painkillers. The separate media and legal challenges to Limbaugh are part of a longstanding strategy employed by the political left, according to Mark Levin, director of the Landmark Legal Foundation and a supporter of Limbaugh. "There's no question they've...