Earlier this month Bush returned, trailing far behind in polls, and the audience in the same speaker's hall was less than a third the size. The reception was polite, but no one was leaping from the folding chairs.
The former Florida governor seemed unfazed.
The contest, he told reporters before his latest stop at St. Anselm College, "will look a lot different when we're gathered back together after Christmas and when we're gathered in the second, third week of January, the fourth week. ... It always is different."
Indeed, New Hampshire, which traditionally holds the first presidential primary, has a history of unpredictability, resurrecting candidates given up for dead, spurning front-runners or elevating also-rans with late-developing shifts in sentiment.
This time, the three contenders with the most to gain or lose are Bush, Ohio Gov.
Their strategies are also virtually the same: survive Iowa, which kicks off the nominating process with its Feb. 1 caucuses, then win New Hampshire eight days later -- or at least run strongly enough to emerge as the alternative to Trump, Texas Sen. Ted Cruz or whoever else stamps himself the favorite of social conservatives who tend to rule the caucuses.
No candidate has spent more time and effort in the state than Christie, who was relegated to the Republican second-tier debate in November before a surge in New Hampshire polling placed him back on the main stage in December.
His roots in the Northeast help, as does his forceful persona at a time of renewed anxiety over terrorism. His endorsement by the Manchester Union Leader, the state's largest and most influential newspaper, doesn't hurt.
But more than that, Christie has been a virtuoso of the town hall meeting, a New Hampshire set piece that requires presidential hopefuls to take all comers until their questions, or the nighttime, is exhausted.
Christie, who used a boisterous series of town halls to promote his gubernatorial agenda -- and build a national following -- has held more than 50 of the open-ended sessions in New Hampshire. (Kasich has held more than three dozen.) An excerpt from one Christie appearance, where he delivered a passionate call for treating rather than punishing drug addicts, has been viewed on YouTube more than 8.5 million times.
"Some candidates can go shake every voter's hand in New Hampshire and still lose miserably because they don't have the ability to really connect with people," said Drew Cline, the Union Leader's former editorial page editor and a supporter of Florida Sen. Marco Rubio. "There's a certain bit of talent, charisma, charm that you have to have to make that kind of campaign pay off for you, and not everybody can pull that off."
During his recent stop at St. Anselm College, it was Bush's turn for the requisite grilling.
He sat at the front of a hall lined with photographs of candidates past, including his father, George H.W., mingling with supporters on the banks of a lake and his brother, George W., smiling broadly at an outdoor rally.
For 40 minutes, the former governor answered every question he was asked: about immigration, terrorism, his Latin American studies in college, how he fends off fatigue on the campaign trail -- a workout, including 100 sit-ups a day -- and what historical figures or celebrity he would invite to the White House. "I wouldn't invite Donald Trump," he said dryly.
Afterward, he posed for photographs and shook hands with dozens of people who lined up.
Less than two months before the Feb. 9 contest, the Republican race seems unusually wide open, a fierce competition owing to the large field of serious candidates and the opening that Bush's diminished status provides others on the center-right hoping to emerge as the GOP establishment favorite.
Polls show Trump leading in New Hampshire but averaging less than a third of the vote, followed at some distance by more than a half-dozen others -- Bush included -- bunched closely together.
More significantly, the latest University of New Hampshire survey found fewer than two in 10 likely Republican primary voters had firmly decided whom to support.
Chris Williams is among those still shopping, narrowing his choice to three possibilities after ruling out Trump (too divisive) and Bush (a good fellow, but too much the career politician).
Williams admires Kasich's performance as Ohio governor, especially his work helping turn around the economy, and appreciates the fact that Carly Fiorina, the former Hewlett-Packard chief, comes from outside politics. Williams also likes the 44-year-old Rubio "because he's young and I think brings a fresh perspective."
But Williams, 40, who runs the southern New Hampshire chamber of commerce, is a long way from settling on a candidate. "I'm hoping to see each of them quite a bit more before February," he said.
That is the New Hampshire way; already, the Republican hopefuls have staged nearly 1,000 campaign events across the state, an easy drive from one side to the other, according to a tally kept by New England Cable News.
With so many GOP hopefuls fighting the same fight, the question is what, if anything, will distinguish any one of them.
Tom Rath, a Republican strategist and Kasich supporter who took part in his first presidential primary in 1964, answered succinctly: "Who the hell knows?"
One of them could have a galvanizing moment, he said, like Ronald Reagan in 1980 when he batted down a moderator trying to shush him at a Nashua debate, or rise to some unforeseen event just before the primary.
"A number of people could catch fire and can do that in just four or five days," Rath said.
Bush seemed to suggest as much as he wound down his remarks at St. Anselm College, speaking perhaps as much to himself as the modest gathering of young professionals.
"Be big," he told them. "Be bold. ... Be alive. And don't worry about it being planned out. My toast is for all of you to embrace the unforeseen."
Barabak reported from San Francisco and Mehta from Goffstown and Manchester, N.H.
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