I see this posted often...would like to know just how you know this to be factual? IMO, Huckabee has his OWN ambitions, which have absolutely nothing to to with Mitt. I wager that Huckabee will be a candidate in 2012.
Romney supporters are so invested in Mitt, the "Savior" and the ingrained "persecution" complex of the mormon culture that they see everything done by other candidates as a grand conspiracy against their homie. Sounds pretty much like a group paranoia to me.
Or, to borrow a delusion from the Mittbots, perhaps this is a ploy by the Romney camp to eliminate a competitor for 2012.
There is very little difference between McCain and Huckabee.
Both are Pro-Life
Both support Illegal Immigrants
McCain was against Bush tax cuts - Huckabee raised taxes
So know real ideological differences between the McCain and Huckabee.