Michael Sherer remembers 2008:
As with Gingrich today, Huckabee reacted to the spots by officially refusing to go negative. Instead, he attacked Romney for going negative, and then showed reporters a campaign ad he had decided not to run attacking Romney. It worked for Huckabee. In Iowa in late 2007, the negative attacks only confirmed voters suspicions of Romney as a robot candidate without clear conviction. … The question this time is whether the field and the candidate are different enough to produce a better result for Romney.
(The above web ad is from American Bridge, a Democratic Super PAC)