As the new season of Saturday Night Live gets under way on Oct. 4, Darrell Hammond-the show's chief political impersonator, once Bill Clinton and, at this year's Emmy Awards, the squinty-eyed Donald Rumsfeld-can't wait to contort himself into the likeness of former Vermont Governor Howard Dean. "I'm sitting there with writers, saying, 'Please give me this assignment so I can do this.' I hope I can get into Dean, because he's so bloody-he's so himself," he said. "What's so interesting about Dean is he appears to be an impassioned man and says, 'Damn the theatrics of the whole thing, I've...