What does this mean?
It means that the Romney campaign has decided that the press won't cover Huckabee fairly -- in Iowa.
It means that the campaign is willing to risk a backlash in order to hit Huckabee where he is most vulnerable.
It means their internal polls confirm what the public polls are saying.
It means that Romney is now wedded to an engagement model -- that is, he now has to attack Huckabee daily.
The decision to run this ad is not universally popular within Romney's campaign, judging from some early e-mail traffic.