Jeb Bush has a new nemesis, and it isn’t Donald Trump.

Presidential hopeful, Ohio Gov. John Kasich (R), is quietly rising in the polls in New Hampshire, capitalizing on a strong debate performance where he seemed at ease in the spotlight.

With many in the Republican Party seeking to find a Trump slayer, Kasich’s late-summer surge is threatening to steal away the mantle of establishment favorite that Bush had long been expected to claim.

"Of all the candidates out there in terms of corralling the establishment voters, Kasich is a clear and present danger of taking them," Republican strategist Ford O'Connell told The Hill. 

The threat to Bush is clear.

The former Florida governor is an underdog in the Iowa caucus, and if current polling holds, might not even finish in the top five for the race to the White House.

That lends added importance to New Hampshire, the first primary state in the nation and a reliable bellwether for the nomination.
Should Kasich top Bush in the state, strategists say, the race could change in an instant.

“[Kasich] wants to become the establishment front-runner, and he can do that by beating Jeb in New Hampshire," said Matt Mackowiak, another GOP strategist.

But beating Bush will be no easy task.

His fundraising network is vast, thanks to the connections built up over the years by his family. The super-PAC supporting Bush’s candidacy has already raised more than $100 million, and his campaign is expected to stockpile cash at a rapid pace. 

Bush also has access to some of the Republican Party’s best advisers, strategists and policy minds, as many of them served in the administrations of his brother and father.

"Jeb's been consistent since day one in really calling out Washington" and showing his own merits, said Rich Killion, Bush's New Hampshire strategist, mentioning issues such as taxes and school choice.

"Every candidate is still in the introductory stage of introducing themselves to Granite State voters," Killion continued. "Jeb Bush has never run for national office before. His toes are on the starting line, just like everyone else."

But Bush’s tepid showing in the first GOP debate, followed by a few awkward statements on the campaign trail, have halted some of the momentum he appeared to build earlier this summer — and Kasich is filling the void.

A survey released this week by the left-leaning Public Policy Polling (PPP) found Kasich in second place in New Hampshire, thanks to increased support among moderate voters.

Kasich took 11 percent support in the poll, followed by former business executive Carly Fiorina (10 percent), Bush and Wisconsin Gov. Scott Walker (7 percent each) and retired neurosurgeon Ben Carson (6 percent).

PPP's survey also showed Kasich as the Republican in the state who would present the strongest challenge to Hillary Clinton, the Democratic front-runner.

A Boston Herald/Franklin Pierce University poll released days after the first GOP debate earlier this month found Bush and Kasich neck and neck at 13 percent and 12 percent in New Hampshire, respectively.

Still, Trump remains at the head of the pack both in New Hampshire and nationally, in some cases leading the other 17 candidates by double-digits. 

"You have Donald Trump and the rest of the field," said David Winston, a Republican pollster. "I don't think the mini-primaries are clear yet."

Regardless, "New Hampshire is the spark," O’Connell said, noting that it's difficult to gain traction in the other early-voting states without big national poll numbers and attention.

"If [Kasich] can actually win New Hampshire, then the game board changes," O'Connell added.

Kasich was one of the last candidates to join the 2016 race, which gave him just enough of a bump in the polls to land a spot in the first Republican debate on Aug. 6.

Since then, Kasich — a former nine-term congressman — has been traveling around New Hampshire for around a dozen town halls and events, all while enjoying record approval ratings back home in Ohio.

He’s picked up several big-name endorsements, including former New York Sen. Alfonse D'Amato (R), Alabama Gov. Robert Bentley (R) and former Senate Majority Leader Trent Lott (R-Miss.). 

He's also been backed by Thomas Rath, a veteran operative and former New Hampshire attorney general, and former New Hampshire Sen. John E. Sununu, who is now a top adviser.

"If he's successful in the first three or four primary states, then that momentum will continue," Sununu told The Hill.

"I think one of the biggest challenges right now is that there are 17 people in the race," he added. 

Kasich’s rise has been aided by a super-PAC, New Day for America, that has spent $4 million in New Hampshire since mid-July, an official told The Hill.

"It's very clear with the governor moving into second place in New Hampshire, the more they see of Gov. Kasich the more they like him," Matt David, the group's chief strategist, told The Hill.

Sources involved with the Kasich super-PAC say it plans to extend its ad buy, including on the digital front, ahead of the next Republican debate in September. 

The Bush camp appears ready to fight back.

The super-PAC that supports Bush is expected to start airing TV ads in New Hampshire by mid-September. The ads are part of a $10 million media blitz that includes South Carolina and Iowa, according to the Associated Press.

Bush is headed to New Hampshire in the coming days for his 12th appearance since March, Killion said. Kasich is scheduled to visit the state on Tuesday and Wednesday.

Top aides in New Hampshire for both campaigns caution that the race is still in its very early stages. 

Sununu said the vast majority of voters won't tune into the race until after Labor Day, while Bush's strategist noted that Granite State voters "habitually, instinctively and almost deliberately choose to decide late."

"That's why you really have to work it. You have to invest the time and attention and the care to put yourself out in front of the voters," Killion said.

"You want to compete everywhere, and this is a great place to compete," he added. 

Bush and Kasich share many similarities; both have executive experience as governor of a large swing state, and both have broken with the rest of the field on issues such as immigration and Common Core education standards.  

"Bush's theory is inclusive conservative, Kasich's is compassionate conservative," O'Connell said.

Bush’s ability to compete aggressively in all the early-voting states is one major advantage, strategists note. While Bush’s candidacy might be able to survive a poor showing in New Hampshire, a defeat there for Kasich could be a fatal blow.

"I think Kasich needs New Hampshire more than Bush does. He's going to be nowhere near [him] in Iowa and South Carolina," Mackowiak said.