Why do you think no one attacked Mitt Romney in the republican debate? Are they making him the frontrunner?

It seems like Cain, Bachmann, Pawlenty or Gingrich don't care so much about winning. Romney is killing them in polls but they didn't try to do anything about it. I guess they're trying to make Obama go down as a team and they've already decided it's gonna be Romney who's gonna deliver the final blow.