Former President Bill Clinton has backed away from harsh criticism of Barack Obama after his attacks in South Carolina turned many African-American voters away from the presidential campaign of his wife, Hillary, and caused them to rally around Obama. But Democratic insiders worry that Bill is still a loose cannon, ready to go off at any moment. One problem, according to a former Bill Clinton adviser, is that there are few people "who can tell Bill honestly when he messes up." Some Hillary aides are counting on Maggie Williams, her former White House chief of staff and now a senior campaign adviser, to play the disciplinarian. But nearly everyone in Hillaryland agrees that someone will need to pull Bill back if he strays off course again.