Yesterday John McCain stopped in Racine, Wisconsin for a town hall meeting where he fielded a question about his "Celebs" ad equating Barack Obama with Paris Hilton and Britney Spears. Didn’t this commercial and its recent predecessors violate McCain’s self-imposed ban on mudslinging? It’s a rare moment of accountability in McCain’s town hall meeting format, and the candidate meanders his way toward proclaiming that "We’re proud of that commercial."