Mitt Romney was poised to win his second straight battle in the race for the Republican U.S. presidential nomination on Tuesday but it remained to be seen whether his anticipated victory in New Hampshire would be sizeable enough to put to rest doubts about his candidacy.
The former investment firm chief maintained a sizable lead in opinion polls in the New Hampshire primary contest despite rivals' fierce 11th-hour attacks painting him as a heartless corporate raider who enjoys cutting jobs.
Romney's stint as a relatively moderate governor of neighbouring Massachusetts has also caused many conservative Republican voters to view him sceptically.
The New Hampshire primary is the second contest in the state-by-state battle for the Republican presidential nomination to face Democratic President Barack Obama on November 6. Romney narrowly won the first contest, the Iowa caucuses, on January 3.
Ron Paul, a U.S. congressman known for his libertarian views, and Jon Huntsman, a moderate former U.S. ambassador to China, appeared to be in a battle for second place in New Hampshire, the small New England state known for its independent streak and outsized role in presidential campaigns.
A multimillionaire who says his experience as head of private-equity firm Bain Capital would help him spur America's economy as president, Romney might face a bigger challenge in the next primary in South Carolina on January 21, where the economy is weaker and conservatives make up a larger slice of the electorate.
Romney last week beat Rick Santorum, a conservative former U.S. senator from Pennsylvania, by a scant eight votes in Iowa. If he wins New Hampshire, he would be the first non-incumbent Republican to win both states since they took on their first-in-the-nation status in the 1970s.
But support is lukewarm among even some who said they voted for him in New Hampshire.
Out of them all, he was the lesser evil, said Mary Jane Bevin, 53, a Windham nurse. I'm very concerned about the economy and jobs.
A resounding victory by Romney could buttress the notion that he is the inevitable Republican nominee to face Obama. If Romney wins, but by a margin smaller than expected, the result could prompt fresh questions about whether he has won over the broader Republican electorate.
Romney would need to finish at least 10 percentage points ahead of the second-place contender and capture a third of the vote or more to be considered a strong victor in New Hampshire, where he has been long considered the favourite.
Mitt Romney's biggest asset is the large number of candidates in this group that are dividing up the remainder of the vote, said David Paleologos, director of the Suffolk University Political Research Center in Boston.
Santorum has trailed in New Hampshire polls. Newt Gingrich, a former speaker of the House of Representatives, is also well behind.
Romney visited a polling station in Manchester and said he hoped the state would make a big statement for his candidacy. You see great enthusiasm, he said.
A strong win in New Hampshire would provide momentum going into South Carolina and the next primary, in Florida on January 31. Romney leads in both states and victories there would all but sew up his nomination.
A nationwide Reuters/Ipsos poll on Tuesday showed Romney preferred by 30 percent of Republican voters, way ahead of his rivals. He also has narrowed the gap against Obama but still trails by 5 percentage points in a head-to-head matchup.
It was unclear how much damage had been done by attacks from opponents who accused Romney of being a job killer in the 1990s when he bought and restructured companies as head of Bain.
Romney didn't help himself on Monday when he said: I like being able to fire people who provide services to me.
He was discussing the need for greater competition between health insurance companies. Rivals seized on the remark, in a sharp departure for a party that is traditionally friendly to business interests.
Gingrich, brooding over negative attacks from Romney and his backers in Iowa, has launched the toughest assault.
'PREDATORY CORPORATE RAIDER'
Mitt Romney was not a capitalist during his reign at Bain. He was a predatory corporate raider, a 27-minute video produced by a pro-Gingrich group said.
Gingrich has also cited a Reuters report that takes an in-depth look at a Kansas City steel mill that was driven into bankruptcy under Bain's ownership.
The attacks have prompted some conservatives to cry foul. The National Review magazine posted an editorial on Tuesday calling it foolish and destructive to attack Romney for his investment successes.
The onslaught took on new life during weekend debates in New Hampshire. But Romney retains a strong core of support in the small state of 1.3 million people, where he owns a summer home.
I saw him pull the Olympics out of the toilet. I saw him work as a businessman, he sees what needs to be done and gets it done, said Dennis Hamson, 58, a nurse from Londonderry.
New Hampshire voting stations will be closed by 8 p.m. EST (0100 GMT). About 250,000 people are expected to vote in the Republican primary while 75,000 are likely to vote to endorse Obama's re-election.
Romney's rivals were targeting undecided voters in a fierce battle for second place. Santorum, who nearly won Iowa by appealing to social conservatives, has not seen that message resonate in New Hampshire.
I'm socially liberal. I could never vote for Santorum, said student Cody Love, 21, who voted for Huntsman in the state capital, Concord.
(Additional reporting by Ros Krasny and Mary Milliken in Manchester and Patricia Zengerle and Jeff Mason in Washington; Writing by Andy Sullivan; Editing by Will Dunham)