New Hampshire Republican Gov. Chris Sununu was adamant Tuesday that former President Donald Trump cannot become the GOP's 2024 nominee because he would essentially guarantee the re-election of President Biden, which could also lead to Vice President Kamala Harris ascending to the Oval Office.

The popular governor, in his fourth two-year term, spoke to "Your World" after deciding against launching a presidential bid, saying he will not endorse Trump in the Republican primary but could, however, decide to back one of the other candidates before or after his state's first-in-the-nation contest.

Sununu said Trump "represents the past [and] wants to relitigate the past" while failing to represent "good Republican values."

"He's separating himself from the field for all the wrong reasons," he said. "[…] He cannot mathematically win in November of ’24. So right there, we've got to find another candidate and use Iowa and New Hampshire and some of the earlier states to really see who has the muster, who can deliver on a good presidential run."

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Trump and Governor Sununu

Former President Donald Trump and Gov. Chris Sununu (Shane Bevel/Elizabeth Frantz)

When asked why he chose not to run, Sununu said his skill at this juncture is engaging with younger voters and independents to support what he hopes is a Trump-less Republican ticket.

Host Neil Cavuto also noted how Sununu's father, ex-Gov. John H. Sununu, was "instrumental" in George H.W. Bush's successful campaign – which led to his appointment as chief of staff. Chris Sununu's brother, John E. Sununu, served both in the U.S. House and Senate from the Granite State.

Trump recently fired back at Chris Sununu's continued critiques, calling the governor "nasty" and suggesting his reticence to launch a 2022 Senate bid against Sen. Maggie Hassan, D-N.H., cost the GOP an easy win.

"He could’ve really made an impact… He probably would’ve easily won because of the family name… And that would have been a tremendous thing," Trump said in April, adding Sununu instead decided to "play games" in regard to a potential presidential bid.

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New Hampshire Gov. Chris Sununu

Gov. Chris Sununu said Trump "represents the past [and] wants to relitigate the past" while failing to represent "good Republican values." (Fox News)

Sununu said the model his father set for the Bush the elder could happen in regard to himself.

"Look, if I find a candidate I really like and want to get behind, that can really carry that message to a winning momentum, not just through the primary, but through 24 and help other candidates, that's exactly what I'm willing to get behind," he said.

"And I couldn't tell you who it is right now. I don't think anybody really good because we're still so early on."

Sununu stressed he will not support Trump in the primary, saying the Floridian continues to play the "victim card" and look backward rather than forward.

He claimed Trump may be able to win the primary, but would hand Biden a second term in the general. Given speculation about Biden's health and mental faculties, Sununu said it could be Trump that therefore hands America a "President Kamala Harris."

"Donald Trump wouldn't even win Georgia," he said. "And if you're a Republican candidate that can't even win Georgia and would actually cost us other seats, then no, we have to take a hard pass at that. Because what it means is if you support Trump and he gets the nomination, Biden ends up the winner."

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Kamala Harris

Vice President Kamala Harris (Peter Zay/Anadolu Agency via Getty Images)

"I don't even know if Biden could finish out a second term. So what happens then? We now got Kamala Harris as president. Well, thank you to all the Trump supporters out there: You've just given [us] Kamala Harris as our next president."

Cavuto responded by asking if Sununu was incidentally following a key paradigm from the 2020 race, where former Florida Gov. Jeb Bush was widely considered a shoo-in but lost to the populist upstart Trump.

"No," Sununu replied. "There's no way Donald Trump can beat Joe Biden in November."

He called Trump a "three-time loser" and blamed him for Republican losses in the 2018, 2020 and 2024 elections, saying the GOP should currently have at least 53 U.S. Senate seats.

Addressing Trump, he added: "Thank you for your service. This is not personal. This is just about winning."

North Dakota Gov. Doug Burgum and former New Jersey Gov. Chris Christie are expected to launch GOP bids imminently.