Romney needs to take it to Bob Schieffer — he should treat Obama the way he treated Rick Santorum, and treat Bob Schieffer the way he treated Rick Perry. There are three people on the stage — two of them are your opponents: knock them both off stage. Do not treat Bob as an impartial participant.
Schieffer snarling and Romney calmly putting him in his place would come off as no-nonsense, presidential behavior.
After the Crowley idiocy, Romney can make hay with the partisanship and unreliability of the moderators.