My dictionary defines "moderator" as "the nonpartisan presiding officer of a town meeting." On Thursday, PBS anchor Gwen Ifill will serve as moderator for the first and only vice presidential debate. The stakes are high. The Commission on Presidential Debates, with the assent of the two campaigns, decided not to impose any guidelines on her duties or questions. But there is nothing "moderate" about where Ifill stands on Barack Obama. She's so far in the tank for the Democratic presidential candidate, her oxygen delivery line is running out. In an imaginary world where liberal journalists are held to the same...