CONCORD, N.H. -- New Hampshire voters are flooding polling stations today in the state's first-in-the-nation primary, while presidential candidates make last-minute appeals for votes -- in some cases, turning polling stations into mob scenes.

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Republican Sen. John McCain and former Massachusetts Gov. Mitt Romney collided in the primary, rivals in urgent need of a triumph in the campaign for the White House. Sens. Barack Obama and Hillary Rodham Clinton squared off in the Democratic race.

By custom, the first handful of votes was cast, at midnight, in Dixville Notch, the state's northern-most precinct.

By tradition, the first primary held the power to propel winners into the rush of primaries that follow -- to send the also-rans home for good.

And by registration, New Hampshire's balance of power rested with its independent voters, more than 40 percent of the electorate, neither reliably Democrat nor Republican, with the power to settle either race, or both.

Turnout was reported to be brisk on a spring-like day.

McCain, an Arizona senator, in particular, appealed for their support in the run-up to the primary. He battled Romney, the former governor of next-door Massachusetts, and to a lesser extent Mike Huckabee, the former Arkansas governor who won last week's Iowa caucuses.

"It has all the earmarks of a landslide with the Dixville Notch vote," an upbeat McCain quipped as his campaign bus headed to a polling place in Nashua.

Former New York Mayor Rudy Giuliani, former Tennessee Sen. Fred Thompson, Texas Rep. Ron Paul and California Rep. Duncan Hunter completed the Republican field.

Obama, too, hoped independent voters would come his way, as they did last week in Iowa, where he won the first test of the campaign. Clinton, the New York senator and former first lady, ran third in Iowa. Former Sen. John Edwards of North Carolina was second.

Obama drew huge crowds as he swept into New Hampshire and as the front-runner drew plenty of attacks from Clinton and her husband. Asked if he expected more, Obama said, "Oh, I don't think it will be just in the next few days. I think it'll be, you know, until I'm the nominee or until I quit." He said he understood their frustration.

Clinton, for her part, retooled her appeal to voters on the run. She lessened her emphasis on experience and sought instead to raise questions about Obama's ability to bring about the change he promised.

Win or lose, she said she was in the race to stay -- never mind Edwards' suggestion that the voters of Iowa had told her that her presence was no longer needed.

There was no letup in the television ad wars.

TNS Media Inte ll igence.cmag, a firm that tracks political advertising, said Clinton spent $5.4 million to reach New Hampshire voters, and Obama spent $5 million. The total for Edwards was $1.7 million, reflecting a smaller campaign treasury. New Mexico Gov. Bill Richardson, the fourth candidate in the race, could afford about $500,000.

As was the case in Iowa, Romney spent more than his rivals combined on television for the New Hampshire primary.

After losing Iowa, he could ill afford another defeat after basing his campaign strategy on victories in one or both states. Reflecting the stakes, he clashed in weekend debates with Huckabee over the Iraq war and with McCain over immigration as he tried to right his campaign.

On Tuesday, Romney put a positive face forward. "The Republicans will vote for me," he said. "The independents will get behind me."

McCain, too, was in need of a victory. Once the perceived front-runner, he suffered through a near-death political experience last year when his fundraising and support collapsed. He rallied, and by the final days of the New Hampshire race, held a celebration of sorts to mark his 100th town hall meeting in the state he won eight years ago.

Record Turnout Expected

A record turnout is expected for New Hampshire's primary. As many as 500,000 voters are expected to cast a ballot, reported WMUR-TV in Manchester, N.H.

Some polling locations turned into mob scenes when candidates stopped by to shake hands. At the Broad Street Elementary School in Nashua, the crowd of supporters there was so big that voters complained and a poll worker pleaded with McCain to leave. Seconds later, the bus pulled away.

One McCain supporter became slightly frustrated when she couldn't get into the school because of the crowd.

"I'm trying to vote for McCain, and I can't get in there," she said.

Another crowd grew when Mitt Romney showed up later.

Some voters went to the polls knowing their choice, but some couldn't make a choice until it came time to cast a vote.

"It was very, very difficult," voter Jen Legay said. "I had no idea."

Legay said she ended up voting for Hillary Clinton, a decision she made in the voting booth.

"It was down to the last three seconds, and then I was, like, 'I'm going for this choice,'" Legay said.

Other voters said they were also having a hard time deciding, but not because they disliked the candidates. They said they were trying to choose among their favorites.

"I think a lot of candidates have pretty good credentials," said Cal Bowie, who voted fore McCain. "And so there are probably a lot of these candidates I could've lived with as president."

Some voters said they were still confused at what they saw as mixed messages from some of the candidates.

Some polling locations turned into mob scenes when candidates stopped by to shake hands. At the Broad Street Elementary School in Nashua, the crowd of supporters was so big that voters complained and a poll worker pleaded with McCain to leave. Seconds later, the bus pulled away.

Link: Local N.H. Coverage

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