[T]he campaign has something of a shellshocked feel, as staffers privately chew over a blowup last week where internal frictions flared into the open. Clinton campaign operatives say it happened as top Clinton advisers gathered in Arlington, Va., campaign headquarters to preview a TV commercial. ‘Your ad doesn’t work,’ strategist Mark Penn yelled at ad-maker Mandy Grunwald. ‘The execution is all wrong,’ he said, according to the operatives. ‘Oh, it’s always the ad, never the message,’ Ms. Grunwald fired back, say the operatives. The clash got so heated that political director Guy Cecil left the room, saying, ‘I’m out of here.'”