The only way that USC get's a shot at a co-National championship is this:
Alabama loses (already happened)
Texas loses to Ohio state tonight (USC whupped Ohio State)
As for the Florida/Oklahoma game, not sure which one losing does for USC's chances. I'm going to say that it doesn't matter who wins, but if one team wins by a large margin, that will help USC's chances. Maybe better if FL beats OK by 30 points or more???
I think the thing that upsets me is ... Utah is totally out of this conversation. Why??? They are the only undefeated left and beat former #1 team Alabama ... badly.