Want to Check That Fact? For V.P. Debate Viewers, Just Scan the Code.

CBS is experimenting with a novel way to offer real-time fact-checking of the vice-presidential debate on Tuesday. Just don’t expect the moderators to frequently jump in.

The journalistic dilemma of how to fact-check national candidates on the debate stage has cropped up again and again in the 2024 election.

Should CNN’s moderators — who were relatively passive when President Biden debated former President Donald J. Trump in June — have been quicker to interject? Should ABC’s moderators — who politely but firmly clarified several of Mr. Trump’s outlandish claims at the second debate on Sept. 10 — have stayed quiet?

Moderation is an art, not a science. But CBS News, host of Tuesday’s vice-presidential matchup between Senator JD Vance and Gov. Tim Walz, is using technology to try something new.

A QR code — the checkerboard-like, black-and-white box that can be scanned by a smartphone — will appear onscreen for long stretches of the CBS telecast. Viewers who scan the code will be directed to the CBS News website, where a squad of about 20 CBS journalists will post fact-checks of the candidates’ remarks in real time.

The code will appear only on CBS; viewers who tune in on a different channel will not see it. (Nearly every major network will simulcast the debate, starting at 9 p.m. Eastern.) But it is a novel approach to guide viewers, already accustomed to watching TV while hovering over a smartphone or laptop, to supplemental journalistic material elsewhere.

“The idea is to give people that second-screen experience,” said Claudia Milne, the senior vice president for standards and practices at CBS News, adding, “The audience can get the takeaway they need in a responsible and smart way.”

CBS said the moderators — Norah O’Donnell, the anchor of “CBS Evening News,” and Margaret Brennan, who hosts “Face the Nation” — would primarily focus on encouraging exchanges between the candidates and enforcing the ground rules, rather than fact-checking.

Mr. Trump and his allies fumed after the ABC debate, personally targeting the network’s moderators — Linsey Davis and David Muir — for the four times that they clarified falsehoods that Mr. Trump had uttered from the lectern. CBS appears intent on making Mr. Vance and Mr. Walz the stars on Tuesday, rather than the network or its on-air talent.

“The goal of the debate is to facilitate a good debate between the candidates, and the moderators will give them the opportunity to fact-check each other in real time,” Ms. Milne said. CBS said it would remind viewers that the network’s approach to a debate was distinct from a one-on-one interview with a candidate, as on “Face the Nation.”

Last week, both campaigns agreed that microphones would remain on throughout the event, a change from this year’s two presidential debates, when microphones were muted while the other candidate was speaking. The issue led to a spat between campaign aides ahead of the Sept. 10 debate between Mr. Trump and Vice President Kamala Harris. (On Tuesday, CBS producers will be able to switch off microphones if needed.)

Mr. Vance and Mr. Walz will each stand at a lectern, the first time since 2008 that vice-presidential candidates have not debated while seated at a table. There will be no studio audience, and the debate will last for 90 minutes, with two commercial breaks of four minutes apiece.

Tuesday’s telecast is the first major debate sponsored by CBS since February 2020, when the network hosted a chaotic meeting of Democratic primary candidates on the eve of the pandemic.

It also comes at a tumultuous time for CBS News, whose parent company, Paramount Global, is in the throes of a protracted merger amid a dwindling of fortunes for traditional broadcasters.

Ms. O’Donnell is leaving the “Evening News” anchor chair after the election to become a senior correspondent. Ingrid Ciprian-Matthews left her job as the CBS News president over the summer, though she has remained as a senior adviser. At the time, she suggested she was stepping down before Paramount initiated sweeping job cuts in an attempt to find $500 million in savings. Those cuts are underway. Last week, Jeff Glor, Ms. O’Donnell’s predecessor at “Evening News,” was let go, along with several veteran correspondents.

Ms. Ciprian-Matthews is one of the overseers of Tuesday’s debate, along with Mary Hager, the executive editor for politics at CBS News, and David Reiter, a senior vice president who leads special events.

More changes could be coming to the network: Skydance, the production company that is merging with Paramount, plans to install new leaders and seek an additional $2 billion in cost savings.

The debate may also be a last hurrah for the CBS Broadcast Center, the network’s scruffy home of many decades in Midtown Manhattan. CBS has sold off other marquee properties like the Black Rock building on West 52nd Street, and local developers have long eyed the low-slung broadcast center, which stretches for nearly an entire city block.

Tuesday’s event will be the first general-election debate to be held in New York City since the final meeting of John F. Kennedy and Richard Nixon in 1960. It will be taped in the broadcast center’s Studio 45, which has a rich history: it was home to “Captain Kangaroo” from 1964 to 1981, eight years of Geraldo Rivera’s talk show and, until this summer, “Inside Edition.”