Newt Gingrich speaks at the New Hampshire Institute of Politics at St. Anselm College in Manchester, New Hampshire November 21, 2011. (ADAM HUNGER/REUTERS)

Gingrich was responding to Romney’s call, on Fox and Friends earlier Monday, for Gingrich to return his Freddie Mac earnings, for which he has come under attack.

Gingrich spoke at a crowded town hall at Insight Technologies, a weapons maker in Londonderry. It was his first stop on a busy day in New Hampshire that will include a one-on-one debate with former Utah governor Jon Hunstman at Saint Anselm College in Manchester and an evening town hall in front of a tea-party group in Windham.

The exchange with Romney, who is also campaigning in New Hampshire, highlighted the degree to which the Republican nominating contest for president has become a showdown between Gingrich and the former Massachusetts governor. Earlier in his town hall meeting, Gingrich told the audience that he is “determined” to remain positive, that he has faith in the American people, “much like Reagan did,” and that “all those negative ads must be a sign that somebody’s desperate.”

“After 25 years in business, Mitt Romney understands how jobs come and go, and what we need to do to get our economy back on track, said Staples founder Tom Stemberg, in a statement sent over by the Romney camp. “If Newt Gingrich is our party’s nominee, the choice in next year’s election will be between two professional politicians, two Washington insiders, two people with no experience in the real world of job creation.”

Meanwhile, Romney himself hit back personally at an event at a lumber mill Monday in Madison.

“Doesn’t [Gingrich] understand how the economy works? In the real economy, some businesses succeed and some fail. That’s how that works,” Romney said. “And you try and encourage the most successful and fortunately for many people, tens of thousands of jobs, actually over 100,000 jobs were created through the investments that we were able to help make and the four enterprises I led were all successful.”

Romney continued:

“There’s a big difference between working in the private economy and working on K Street and working as a lobbyist or working as a legislator or working to connect businesses with government,” Romney added. “If [Gingrich] was working as a spokesman for Freddie Mac, if he was there because of his political connections and then if Freddie Mac fails, I think a fair question is asked: ‘Why did he profit if Freddie Mac failed?’”

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