LACONIA, N.H. — Jeb Bush wanted to run for president as a joyful front-runner, above the fray of the pack. Instead, he heads into the fall campaign as a fighter with a foil: Donald Trump.

There’s a new urgency in Bush’s tone as a candidate. It’s moved from frustration and annoyance with Trump’s constant needling to a willingness to confront the brash billionaire and call him out for his antics.

And though he still relies on the policy-driven arguments that suit his wonkish style, the son and brother of former presidents is also acknowledging what’s powered Trump’s rise: outrage with the political class his family embodies. Such anger alone, he said, cannot prevail.

“I believe that a conservative can win, campaigning with his arms wide open, with joy in his heart, speaking about the hopes and aspirations of the people, being on the side of the people that right now don’t see their lives in the future being better than what they have today,” Bush told a crowded hall in New Hampshire late last week.

Bush’s aides argue there was no “aha!” moment for the former Florida governor that triggered a shift in strategy. Instead, they say, the threat posed by Trump — who has held steady atop polls nationally and in the early voting states for the past six weeks — has awakened an instinctive sense of drive.

“It’s something about Jeb’s makeup,” said spokesman Tim Miller. “He is an extremely competitive person, in all aspects of life. He recognizes that this is a race he has to earn.”

Bush remains viewed by many in the party — as well among his opponents — as the most likely candidate to emerge from the unwieldy GOP field to win the nomination.

That’s due in large part to the more than $114 million Bush has raised for his campaign and allied super PAC — far and away the most of any 2016 White House effort — and the television advertising that money buys. The super PAC is scheduled to begin $21.8 million in advertising in Iowa, New Hampshire and South Carolina this month.

“He’s still the front-runner, though others could compete” said veteran GOP presidential adviser Charlie Black, who isn’t aligned with any 2016 candidate. He predicted the ads will change public opinion.