Ron DeSantis and Gavin Newsom
CNN  — 

Florida Gov. Ron DeSantis is set for a prime-time debate Thursday night in Georgia – but instead of facing his 2024 Republican presidential primary rivals, he’ll square off with California’s Democratic governor, Gavin Newsom.

The 90-minute debate, which starts at 9 p.m. ET and will be moderated by Fox News host Sean Hannity, is being billed by the network as “DeSantis vs. Newsom: The Great Red vs. Blue State Debate.”

The spectacle of two of the nation’s best-known governors – one in the midst of a  presidential campaign; the other widely viewed as a potential future White House aspirant – could offer DeSantis a major opportunity to prove his mettle in front of a large, conservative audience at a precarious moment for his flailing campaign.

It came about after Hannity, in separate on-air interviews, asked the two if they’d be willing to debate. Newsom said in June he was “all in;” DeSantis in August told Hannity, “Absolutely, I’m game.”

At the time, while DeSantis’ presidential bid had gotten off to a slow start, he was still widely seen as the top alternative to former President Donald Trump in the GOP primary.

In the months since, DeSantis’ hopes of winning the nomination have flagged.

Trump has remained a strong front-runner in national and early-state polls. Meanwhile, another rival, former South Carolina Gov. Nikki Haley has gained traction in recent surveys, particularly in the key early-voting state of New Hampshire.

Haley’s hopes of leapfrogging DeSantis to be seen as Trump’s main primary rival got a boost this week when the influential network associated with billionaire Charles Koch announced it would throw its influence and money behind the former South Carolina governor.

The endorsement by Americans for Prosperity Action marked the latest sign that powerful Republican donors are coalescing behind Haley. It could dramatically reshape the Republican field – less than seven weeks before the first GOP nominating contest in Iowa – as the group deploys its vast resources and standing army of conservative activists.

The political operation surrounding DeSantis’ campaign appears in flux after the formation of a second super PAC supporting his presidential bid last week raised questions about discord between the Florida governor’s official campaign and Never Back Down, the first super PAC, which has taken a leading and unprecedented role in advertising and establishing a ground game for DeSantis.

Newsom, for his part, has become a more active national surrogate for Democrats ahead of next year’s presidential election.

Amid hand-wringing among some Democrats about President Joe Biden’s age and low approval ratings, Newsom has been the subject of speculation about a late entry into the 2024 race. However, he shot down that prospect in a September interview with CNN’s Dana Bash.

“The answer is no,” Newsom said. “No ambiguity.”

Newsom also expressed support for Vice President Kamala Harris, a fellow Californian, remaining on the Democratic ticket for 2024.

“Biden-Harris administration – a masterclass in terms of performance, bipartisan deals on infrastructure, bipartisan deals on guns and debt ceiling, on the CHIPS and Science Act,” he said. “I mean, by definition, if I think this administration last two, two and a half years, has been one of the most outstanding administrations the last few decades, and she’s a member of that administration, she gets to lay and claim credit to a lot of that success,” he said.

He also old Bash he has not thought about whether he would make a good president: “I’m not that guy. I’m just not.”

Newsom said Democrats need to get “out of this sort of navel-gazing about Joe Biden, and let’s get going.”

“Let’s get on the train. This train has left the proverbial station,” he said about a month before Minnesota Rep. Dean Phillips launched his primary challenge to Biden in October.