DES MOINES, Iowa - Former House Speaker Newt Gingrich wept Friday as he recalled his late mother's end-of-life illnesses, a moment of poignancy in a notably negative Republican presidential Iowa caucus campaign.

"I do policy much easier than I do personal," Gingrich told an audience of women as he tried to regain his composure. The tears flowed as the former speaker was responding to questions about his mother from a pollster and longtime political ally.

Gingrich's emotional moment came as his rivals engaged in traditional campaign tactics, and as polls suggested large numbers of Iowa Republicans could change their minds before caucuses Tuesday night provide the first test of the 2012 campaign.

Former Massachusetts Gov. Mitt Romney sought to marginalize his closest pursuer in most polls, saying, "I don't think Ron Paul represents the mainstream of Republican thought with regards to issues, particularly in foreign policy."

There was no immediate response from Paul, a Texas congressman who opposes the use of military force to prevent Iran from acquiring nuclear weapons.

At the same time that he said Paul was outside the GOP mainstream, Romney pledged to support whoever wins the party's nomination to oppose President Obama.

Paul's views on Iran have been called into question this week by other contenders, and Gingrich went so far as to say he would not vote for him.

To some extent, Paul stands alone in the field because of his libertarian-leaning views.

Former Pennsylvania Sen. Rick Santorum, claiming momentum based on recent polls, told reporters he recently had the best fund-raising day of his candidacy. Yet he also drew criticism from Texas Gov. Rick Perry for advocating earmarks during two terms in the Senate.

Minnesota Rep. Michele Bachmann became the latest presidential candidate to hold a campaign event with Iowa Rep. Steve King - and the latest to hear him say he was not ready to give his endorsement.

Whatever the effect of Gingrich's tears on the race for the White House, the episode seemed destined to be replayed endlessly on televisions, personal computers, and handheld devices.

That was the case nearly four years ago, when Hillary Rodham Clinton appeared to choke back tears while campaigning in New Hampshire a few days before the state's Democratic primary. The episode also became the subject of intense political analysis. Clinton won the primary in an upset a few days later.

Gingrich was surging in the polls a little more than a week ago but was hit by a barrage of negative ads and has been struggling in recent days. Normally a combative politician, he shed tears as he appeared before a group of mothers and responded to a question from Frank Luntz, a GOP pollster and longtime ally.

Asked about his mother and an event in his life that influenced his policies and views, Gingrich recalled her as happy and having friends before she ended up in a long-term-care facility suffering from bipolar disease, depression, and physical ailments.

"My whole emphasis on brain science comes in directly from dealing with the real problems of real people," he said, his face distorting as he began to cry. "And so it's not a theory. It's, in fact, my mother," he said.

Kathleen "Kit" Gingrich died in 2003. She was 77.

The event drew notice in New Hampshire, where Romney was campaigning a few hours later. As he mentioned his own parents, now deceased, a member of the audience interrupted, "Don't cry."

"I won't cry. But I do, I do. Nothing to be ashamed of in that regard," Romney said.

After months of campaigning and millions of dollars in TV commercials, the polls depicted a race as unsettled and unpredictable as any in the four decades since Iowa's caucuses became the inaugural event in presidential campaigns.

A pair of surveys in the last five days suggested that more than a third of all potential caucusgoers had not firmly settled on a candidate of choice.

The same polls made Romney the front-runner, and his decision to leave for a quick trip to New Hampshire and then return to Iowa and stay through caucus night projected optimism.

Earlier in the day, in an outdoor rally in West Des Moines, Romney was joined by Gov. Christie, who recalled how Obama painted himself four years ago as the candidate of hope and change. "We are hopeless and changeless, and we need Mitt Romney to bring us back," Christie said.

Looking to gain traction with conservatives, Perry endorsed English as the national language Friday when a Mason City voter expressed frustration with seeing products carrying directions in multiple languages. The man said he'd like English to be made the official language, and Perry said he agreed with him.

Former Utah Gov. Jon Huntsman, who is skipping Tuesday's Iowa caucuses, is betting his candidacy on a strong finish in New Hampshire's Jan. 10 primary, which is open to independents as well as registered Republicans.

Huntsman entered the presidential contest with great expectations earlier in the year. But national polling suggests he is still largely unknown to many Republican voters. He has also struggled to raise money. On Wednesday, he said he was likely to leave the race unless he finishes in the top three in New Hampshire.