EXETER, N.H.— If you want to understand why former Florida governor Jeb Bush has fallen so far in the polls — and why he should not yet be counted out in his bid for the Republican presidential nomination — it helps to talk to Mark Donlevie.

A recent retiree who lives in nearby Stratham, N.H., Donlevie was among about 200 people who showed up to hear Bush at a town hall here Saturday. He had been an early supporter of Bush but lost his confidence as he watched Bush stumble through the fall. Donlevie was particularly disappointed with the listless candidate he had seen during the early round of debates.

But the candidate he saw in Exeter was more aggressive and engaged than the “low-energy” Bush that frontrunner Donald Trump so often maligns. Bush has also taken to attacking Trump far more directly than the other Republicans.

“How can you bring the passion you are showing today more broadly to your campaign?” Donlevie asked Bush.

Saturday began a new phase of Bush's campaign in New Hampshire, where the first primary will held in February, and where Bush is trying to pry away votes from two other establishment GOP candidates, New Jersey Gov. Chris Christie and Ohio Gov. John Kasich.

Recent polls show Christie in particular is gaining momentum in a state that is more moderate than other early states and that prides itself on its independent streak. Christie also campaigned in Exeter on Saturday, kicking off a bus tour around the state.

Bush believes that a big part of winning here will be to take some of the air out of the Trump balloon. Over and over again, he said that Trump is not a “serious person.”

Asked how he intended to beat Trump, Bush told the crowd: “You’re the answer. The question is, will  New Hampshire want to support a guy who might tarnish this extraordinary reputation that you have?"

“I don’t think Donald Trump is going to survive New Hampshire, to be honest with you, because I have too much confidence in you all,” Bush added.

Donlevie told Bush that he had voted for his father and his brother twice each, and that he had started the race with “a solid feeling” about the man who hopes to be the third member of his family elected to the White House. But his confidence in Jeb Bush had slipped.

Donlevie told Bush that he has been wavering in whether to support Bush, Kasich or Christie. Bush told him not to doubt his commitment.

“First of all, I bring it every day. This is who I am. I’m going to out-campaign people. I can promise you that,” Bush said. “Don’t worry about the energy thing. I can outwork everybody running, and I’m doing it.”

But whether that will be enough, given how badly Bush has lagged and how late it's getting in the primary season, is open to question.

“This is a long process,” Bush pleaded with reporters after the event. “Give me a little air.”

Donlevie, for one, says he is willing to do that.

“It’s not the energy thing that Donald Trump talks about. It’s more a passion,” he said of Bush in an interview afterward. “Maybe he always had it. I came out of this feeling pretty good about him again.”