Wednesday’s Trump-less debate is a breakthrough moment for a fledgling cable network — and a comeback of sorts for Ms. Kelly, a former Fox News star.Eight years ago, Megyn Kelly’s turn as a debate moderator made headlines around the world. Before an audience of 24 million Fox News viewers, she confronted Donald J. Trump about his history of misogynist remarks, setting off a well-publicized feud that helped her leap from cable news to NBC.This week, Ms. Kelly returns to television as a moderator of Wednesday’s Republican debate. A breakout moment may be harder to come by.For one thing, Mr. Trump is almost certainly not going to appear, despite Ms. Kelly’s warm entreaties. (“Mr. President,” she wrote on X, “you would be more than welcome and we would love to have you.”) And her appearance will be seen by a fraction of her old audience: The debate will air on NewsNation, an upstart cable network unfamiliar to many Americans.It is still a milestone for Ms. Kelly, whose career imploded when NBC canceled her show in 2018, after she mused on air about whether white people could wear blackface on Halloween. The ouster followed weak ratings and a series of incidents that suggested her punchy and confrontational style was a poor fit for the serene pastures of morning TV.Ms. Kelly, 53, gradually re-emerged as a conservative podcaster and radio host, stoking the culture war grievances that were her stock-in-trade at Fox. (Her recent posts on X refer to “mask fascists” and denounce the use of the term “pregnant person.”) She signed a deal with SiriusXM in 2021 and has since broken into Top 10 charts for news podcasts and booked big guests — including, in September, Mr. Trump.During that interview, Mr. Trump scolded Ms. Kelly for their famous debate moment, saying, “That was a bad question.” Ms. Kelly gamely replied: “That was a great question!” A few days later, at a rally in Iowa, Mr. Trump called her “nasty.”Ms. Kelly declined to speak for this article. In an interview with Real ClearPolitics, she admitted that she had doubted if Wednesday’s debate, with its undercard lineup, was even worth her time. “Does it matter at all?” she said she asked herself.Ultimately, she said, she decided to participate, suggesting that one of the candidates onstage — Gov. Ron DeSantis of Florida, Chris Christie, Nikki Haley and Vivek Ramaswamy — could, in the event of a Trump criminal conviction or perhaps a health scare, end up as the nominee. “It’s not likely, but who am I to rule it out?” she said.Her attitude is something of a contrast to the unvarnished enthusiasm of anchors and executives at NewsNation, who consider Wednesday’s event, in Tuscaloosa, Ala., a breakthrough moment. NewsNation, which is owned by the Nexstar Media Group and airs 24-hour news coverage on weekdays, outflanked better-known outlets like ABC and Newsmax to secure the broadcast rights for this week’s debate.Elizabeth Vargas, a NewsNation anchor and former ABC News personality.John Lamparski/Getty ImagesEliana Johnson, editor in chief of The Washington Free Beacon, a conservative news site.Taylor Glascock for The New York Times“We’re a brand-new news network, and it’s a fantastic opportunity for us,” said Elizabeth Vargas, a NewsNation anchor and former ABC News personality. Ms. Vargas will serve as a moderator with Ms. Kelly and Eliana Johnson, editor in chief of The Washington Free Beacon, a conservative news site.NewsNation, which started in 2021, has fashioned itself as an independent alternative to more partisan, opinion-fueled channels. “The moderate middle may be quieter or may not make as much of a fuss, but they’re a powerful voting bloc,” Ms. Vargas said. “Those are the viewers we serve.” The network has hired prominent journalists like Dan Abrams, Ashleigh Banfield and Chris Cuomo, the former CNN anchor who was fired over ethics concerns and who now hosts NewsNation’s 8 p.m. hour.Ratings remain low. Year-to-date, NewsNation’s prime-time audience has averaged 109,000 viewers on weeknights, compared with 2.2 million for Fox News, 650,000 for CNN and 264,000 for Newsmax, according to Nielsen. The network says that it has a growing fan base — that prime-time figure is up 73 percent from a year before — and that Wednesday’s showcase can reel in new viewers. The debate, which begins at 8 p.m., will also be shown online and on local affiliates of the CW, a broadcast network owned by Nexstar.The stage for the December 2023 Republican presidential candidates debate, which will be shown on Wednesday on NewsNation.via NewsNationMs. Kelly is not the only Fox News veteran with a major role in the NewsNation debate.Cherie Grzech, who produced 15 primary debates for Fox News before leaving in 2021, now runs NewsNation’s news and political programming. Chris Stirewalt, best-known as the Fox News analyst who defended the 2020 election night call for Arizona — a projection that enraged Mr. Trump, alienated viewers and led to Mr. Stirewalt losing his job — is NewsNation’s political editor.Mr. Stirewalt said he believed in the mission of his new employer. “The shortest distance to securing a habituated audience is to cosset them and flatter them and to reinforce their prejudices,” he said. “The harder thing is to try to be aspirationally fair, and try to report and analyze honestly, not to reinforce existing opinions. It’s a substantially underserved market.”This may be a counterintuitive business model, given the nation’s polarized state, but NewsNation is not alone in trying it out. Jeff Zucker, the former president of CNN, is aiming to acquire The Daily Telegraph, a London newspaper, in hopes of expanding its reach to center-right consumers in the United States.Similar experiments have struggled. Shepard Smith, another anchor who left Fox News, created a straightforward newscast on the financial network CNBC in 2020; it was canceled after two years. Chris Licht, who succeeded Mr. Zucker at CNN, promised to dial back partisan opinion, but his programming efforts failed to jell and ratings plummeted.Ms. Kelly, who has no qualms about expressing strong views, is more opinionated than her temporary partners at NewsNation. Eric Bolling, a former Fox News colleague who is now an anchor on Newsmax, said that would work to her advantage.“She will be the biggest viewer draw of all Wednesday night,” Mr. Bolling wrote in a text message. “Unless Trump shows up!” More