Chris Christie steps up as Mitt Romney attack dog

Chris Christie steps up as Mitt Romney attack dog
New Jersey Gov. Chris Christie shakes hands with volunteers at Mitt Romney's New Hampshire campaign headquarters Nov. 9 in Manchester. (Jim Cole / Associated Press)


Mitt Romney

increasingly mixes it up with his primary rivals, he's unleashing

Chris Christie

to help take on the competition.

The New Jersey governor was on the campaign trail for Romney in Florida on Thursday, and had some choice words for his new chief antagonist in the



Newt Gingrich


"Speaker Gingrich has never run anything," Christie said when asked to compare the two candidates,

, a Scripps Media project. "He's been a legislator. I have to tell you – I don’t think being a legislator is the best calling card."

"Look at the guy we have in the

White House

now: He never ran anything and was a legislator," he continued, linking Gingrich to President Obama.

Christie also dismissed Gingrich as just the latest "flavor of the two weeks," saying his poll numbers are just "as solid as the Cain numbers were, as solid as the Perry numbers were, as solid as the Bachmann numbers were."

Christie endorsed Romney before an October debate in New Hampshire, but has largely been focused on his duties at home since. But with just weeks left before the first nominating contests, he's got a busier campaign itinerary. He'll be in Iowa next week, and said he'll host a fund-raiser for Romney in New Jersey.

According to, Christie downplayed the inevitable running mate talk that comes with such advocacy, even as he kept the door open.

"If it is offered, I'd make the decision I thought was best for me and my family and the country," he said. But, "I cannot imagine it happening. I think someone else will be running with Gov. Romney. Not me."

Romney was himself in Florida this week. A new poll from Insider Advantage put Gingrich far out front of the field in the Jan. 31 primary state, leading Romney 41%-17%.