Perhaps most significantly, at least as far as early polls are concerned, Romney has spent nearly $725,000 since February on television ads highlighting his biography and fiscal conservatism on WMUR-TV, New Hampshire's only network-affiliated commercial station, as well as additional ads on cable stations. Neither McCain nor Giuliani has aired a single television commercial.

"You can't underestimate the importance of having ads right now," said Andrew Smith, director of the University of New Hampshire Survey Center, who has been tracking the race. "It doesn't mean they're going to vote for him necessarily, but he's fresh in their minds."

But Smith added that the polls may also partly reflect Romney's expanding ground effort.

"The campaign itself is working at a much faster pace and a much more intense rate than any of the other candidates on the Democratic or Republican side," he said. "It's the kind of activity you see in the last month of the campaign."

Romney began investing in the state more than two years ago, courting local activists in one-on-one meetings, speaking at party fund-raisers and even hosting a state GOP fund-raiser at his Wolfeboro home in September 2005.

He also used his political war chest strategically to gain traction. Since 2004, the Commonwealth PAC, a political action committee set up by Romney advisers to help him explore a presidential run, has showered local Republican candidates with cash, doling out hundreds of thousands of dollars to candidates he hoped to befriend and to the county and state party committees in New Hampshire and other states.

Over time, he won over a number of local political heavyweights, including Donna Sytek, a respected former House speaker and former state party chairwoman from the heavily Republican southern tier; and Bruce Keough, who narrowly lost the 2002 Republican nomination for governor.

He also recruited Tom Rath, the state's former national committeeman and a longtime New Hampshire campaign adviser to both presidents Bush. Rath's consulting firm is being paid about $12,500 a month for strategic advice by the campaign.

As director of his New Hampshire operation, Romney signed on James Merrill, a young lawyer and a rising star in the state party who served as grass-roots cochairman for President Bush's 2004 campaign in New Hampshire.

These operatives understand the importance of one-on-one contact with voters, and they have packed Romney's schedule with opportunities to meet as many voters as possible.

Last week, Romney squeezed 12 events into a day and a half in New Hampshire, racing from Nashua to the Seacoast and from Laconia to Bedford, promising to enhance America's superpower status by strengthening the military, reinvigorating the economy, and promoting conservative family values.