BURBANK, Calif. — Democrat Hillary Rodham Clinton, who is unlikely to catch rival Barack Obama in pledged delegates, hinted on Thursday that she hoped to persuade a few to back her instead of him. “There is no such thing as a pledged delegate,” Clinton said at a news conference in California, where she has been fundraising. Both Clinton and Obama planned to address the state convention of the North Dakota Democratic Party Friday, where delegates to this summer’s national convention will be allocated. Obama crushed Clinton in the state’s Feb. 5 presidential caucuses, 61-36 percent. The former first lady said...