By Justin Sink and Meghashyam Mali - 01/05/12 01:15 PM EST
Arizona Sen. John McCain (R) came to the defense of Mitt Romney and warned his primary opponent Newt Gingrich, who has launched a series of harsh attacks on his GOP rival, to “be careful about being too angry.”
Gingrich has blasted Romney in recent days for a series of negative super-PAC ads that have hurt the former House Speaker in the polls, going so far as to call his opponent a "liar."
“You’ve got to be careful about being too angry. I’ve never called an opponent of mine a liar,” said McCain on CNN’s "Starting Point" Thursday morning. “That’s a line you just don’t cross. Newt Gingrich is a very smart man, intelligent, and I’m sure he doesn’t need my advice. But I think the people of New Hampshire want to hear your views, your vision and not just attacks on other candidates."
“Politics is a collision sport, not a contact sport. Campaigns are very tough and we're seeing that now. Mitt Romney and I had disagreements — that's why we competed against each other,” said McCain.
But he added that any disagreements were a thing of the past. “As soon as that campaign was over, nobody worked harder or supported me more than Mitt Romney did,” he said.
McCain is a favorite in the Granite State, where he won the Republican primary in 2000, besting eventual nominee George W. Bush, and again in 2008. In 2008, McCain topped Romney in a close contest, pulling 37 percent of the vote to Romney’s 31 percent.
“I am really here for one reason and one reason only, and that is to make sure that Mitt Romney is the next president of the United States,” McCain said on Wednesday when he appeared with Romney at a campaign event. “New Hampshire is the state that will catapult him on to victory in a very short period of time.”
McCain also responded to criticism from former Utah Gov. Jon Huntsman, who said "nobody cares" about McCain's endorsement and downplayed the effect of GOP establishment figures rallying behind Romney.
"Endorsements have limited effect, but I'm pleased in some small way to help Mitt Romney," he said.
"Huntsman is correct — endorsements are helpful, but the performance of the candidate is what makes voters decide.
"I do have a lot of friends here in New Hampshire that listen to my views," the senator joked.
Romney has polled consistently as a front-runner in the state. The most recent Suffolk University/7News two-day tracking poll of likely voters leading up to the Jan. 10 primary finds him with 43 percent support.
Romney, though, has faced strong criticisms from his GOP rivals, who have tried to position themselves as the conservative alternative for primary voters.
McCain seemed to admit that Romney faces a tough fight to secure the party's nomination.
"Is he the perfect candidate? No. Was I the perfect candidate? No," said McCain, insisting that Romney's overall record still left him best positioned to challenge Obama in the general election.
"I believe he has the best chance to defeat President Obama," McCain said during an appearance on "Fox & Friends."
McCain also disputed that he and Romney were "moderates." "I'll match my record as a fiscal conservative fighting for the taxpayers of my state against anybody," he said on Fox.