"If we go on for months and months, we will have the resources to carry a campaign," he said.
The Sunday talk show television appearance followed a series of endorsements Romney has received in recent days, including one from South Carolina Governor Nikki Haley.
Romney was also endorsed over this past weekend by the Des Moines Register, the largest newspaper in Iowa. And his campaign showcased an endorsement from Bob Dole, the Republican nominee in 1996, in an ad in yesterday's Register that quotes the former Kansas senator as saying Romney offers the "best hope" for beating Obama.
Gingrich 'Delighted'
Gingrich, speaking Sunday on CBS' "Face the Nation" program, said he was "delighted" by the Register's endorsement of his rival because the newspaper is "solidly liberal" on its editorial page. He noted his endorsement by the Union Leader newspaper in New Hampshire, which he said has a "reliably conservative" editorial voice.
"I think that indicates who the conservative in this race is," he said.
Gingrich said he "earned" an editorial in the Wall Street Journal on Dec. 17 that criticized him for a lack of candor in business dealings with Freddie Mac, the government-backed mortgage company that paid his consulting business at least $1.6 million after he left Congress.
He said he supports breaking Freddie Mac into four or five companies and would like to see them "weaned" off government subsidies.
"We earned that editorial by not stopping handling this from day one and laying it out," Gingrich said. "I didn't personally get that kind of money. It went to a consulting firm, which had offices in three cities. And the share I got of it was relatively small."