...So says a Candy Crowley fan: Heads I win, tails you lose. Moderators are not participants, and should not interject their personal opinions or beliefs. Unless your are a left wing fascist who wants to control discussion and muzzle the opposition.
if a moderator know that an obvious lie has been said, then he or she should call the candidate out on it. period. if they can't do that, then they should at the very least ask follow up questions 9which they do already) & have the candidate 'expand' on the lie, so they can dig an even deeper hole.