We know how the three debates went...Lehrer was most neutral & let the candidates have at it! Martha got the message from her lib media friends & tried her best to shield Joe Biden (nobody can save an idiot from himself!). I am sure they reached out to Candy & made sure she played defense for Obama every time he was cornered. One good thing came out of Candy's obvious partisan hack job...most people were outraged.
Bob Schieffer would have been as bad as Candy but I have a feeling that he does not want to look as bad as Candy...I am sure he will play defense for Obama by changing topic when Romney presses Obama for lying in the previous debate. As a more seasoned guy, he will do it less blatantly than Candy.
Of course, being the last debate, if Obama starts tanking like the first debate, then all bets are off. It is now or never for the libs...they cannot risk Obama looking like an idiot with his uhs, umms, choppy sentences (he is no orator without his teleprompter) & Bob will take over the debate & start attacking Romney for Benghazi comments, Olympics etc...
Overall, he might be slightly better than Candy in partisanship ...depends on how Obama does?