CNN  — 

New Hampshire Gov. Chris Sununu, a frequent Republican critic of former President Donald Trump, said Monday in an exclusive interview with CNN’s Dana Bash that he will not seek the party’s 2024 presidential nomination.

“We’ve taken the last six months to really kind of look at things, where everything is. And I’ve made the decision not to run for president on the Republican ticket in 2024,” Sununu told Bash.

Sununu’s decision further defines the GOP’s 2024 field and means there won’t be a home-state contender in New Hampshire, leaving the Republican contest in the first-in-the-nation primary state wide open.

Sununu said part of his decision was about the former president and the growing GOP field. Three Republicans – former Vice President Mike Pence, former New Jersey Gov. Chris Christie and North Dakota Gov. Doug Burgum – are all expected to officially announce their campaigns this week.

“I don’t mind who gets into the field, but given where the polls are right now, every candidate needs to understand the responsibility of getting out and getting out quickly if it’s not working,” Sununu said.

The New Hampshire governor, a popular figure in the Granite State, was reelected to a fourth two-year term in the fall. After his victory, he declined to rule out a presidential campaign for months, telling Bash last fall that the Republican Party is “clearly moving on” from Trump.

He reiterated that point on Monday and told Bash that he did not believe Trump could win the general election in 2024.

“The math has shown Donald Trump has no chance of winning in November of ’24. He wouldn’t even win Georgia. If you’re a Republican that can’t win Georgia of November ‘24, you have no shot, and he’s proven that,” Sununu said.

“Not only has he proven it, but the candidates he gets behind in a good conservative state like Georgia lose the race. His messaging doesn’t translate,” he added.

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Sununu argued that if Republicans nominate Trump, they are helping President Joe Biden.

“If Republicans nominate him, then we’re saying a vote for him in the primary is effectively a vote for Joe Biden. I mean that’s ultimately how the math will play out,” Sununu said.

But while Sununu has previously said that he didn’t think Trump would be the GOP nominee, he struck a different tone on Monday. “That’s one of the reasons why I’m not running – because he could be the nominee if more folks don’t start talking about what the Republican Party is about, not just what Donald Trump is about,” Sununu said, arguing that Trump isn’t “even a real Republican.”

Asked whether South Carolina Sen. Tim Scott, former South Carolina Gov. Nikki Haley or Pence could beat Trump, Sununu said, “I think so. Look, I think almost any candidate has a path. I think the debates will be really critical.”

The New Hampshire governor said other GOP candidates need to call out Trump and be “very candid” and talk “with the same voice” to try to differentiate themselves and the Republican Party from the former president. But he cautioned that the field needs to narrow before it’s too late – preferably by November or December. “We’re not going to wait ‘til Super Tuesday to winnow it down to a one or two candidate race,” he said.

And even without being on the debate stage himself, Sununu said he’ll still play a role in countering Trump – perhaps being “a little more unleashed.”

“I’ll still be debating him because he is not what the future of this party is about. So I’m not going away. I’m not going to stop having a voice,” he said, offering to help “any candidate who wants to know how to debate the right way.”

Sununu has previously said the Republican Party’s messaging needs to be more inspirational and less combative, a tonal shift from several prominent GOP politicians.

“I think the Republican Party as a whole just wants to get out and fight as opposed to saying, ‘Look, let’s remember what we’re about – limited government, local control, believing in individual responsibility. That’s the live-free-or-die spirit of New Hampshire, and the model works really well,” the governor told Bash then.

Sununu, who voted for Trump in both 2016 and 2020, has previously told CNN that whoever becomes the GOP nominee will have his support.

“Yes. I’m a Republican. I’m going to support the Republican nominee, because I can guarantee they’re better than any of the Democrats that will likely sit in that presidential seat,” Sununu said in a February interview with CNN’s Alisyn Camerota. “I don’t think it’s going to be Donald Trump, but yeah, I’m going to support the Republican nominee, to be sure.”

This story has been updated with more from Bash’s interview with Sununu.