He’s already agreed to a one-on-one with Huntsman.
The Huntsman debate is stategy... I think he is hoping to prop up Huntsman to cut into Romney’s lead in New Hampshire. Face it the only candidate in the race that draws from Romney is Huntsman, it is to Gingrich’s benefit to build up Huntsman at Romney’s expense
Probably because (and I know its going to hurt you to hear this) he & Huntsman disagree a hell of a lot more than he and Santorum do.