More than 51 million TV viewers tune in to watch Trump-Biden debate

 Over 51 million TV viewers tuned in to watch Thursday's US presidential debate between Democratic President Joe Biden and Republican rival Donald Trump, according to final Nielsen data.

The number is about 30% lower than the 73 million people who watched the candidates’ first face-off in 2020, and among the three lowest-rated first presidential debates since 1976.

The relatively low number compared to past debates in recent election cycles could be indicative of low voter enthusiasm for both candidates. It does not capture the full extent of online viewing, which has grown in popularity as traditional TV audiences decline.

Media experts were looking to see how a new format by host CNN would play out, and whether it would provide a template for future debates. The restrictions of that format - which included the option for CNN to mute the candidates' microphones - imposed some discipline on the candidates and should be emulated by other networks, three media experts said.

CNN, which held the exclusive rights to present the debate, allowed candidates two minutes for each answer and one minute for rebuttals, and muted their microphones if they exceeded those limits. The studio did not have an audience, and moderators Dana Bash and Jake Tapper did not fact-check the candidates in real time.

CNN defended itself against the criticism from some media commentators that the absence of real-time fact-checking allowed both candidates to spread false claims.

“The role of the moderators is to present the candidates with questions that are important to American voters and to facilitate a debate, enabling candidates to make their case and challenge their opponent,” a CNN spokesperson said in a statement.

Biden delivered a shaky, halting performance while Trump made a series of exaggerated or false claims that mostly went unchecked by his opponent.

“Without having an audience, you got a sense of who these guys are and what they are,” said Frank Sesno, professor at the School of Media and Public Affairs at George Washington University and a former CNN journalist.

“You got the sense of Trump the attack dog and Biden as something of the policy wonk and the hesitant old man that you saw standing behind that mic,” Sesno said.

Trump and Biden campaign spokespeople did not respond to requests for comment about the CNN format and hosts' performance.

Trump largely refrained from speaking over Biden during the debate, showing the kind of restraint that eluded him during the candidates' first debate in 2020.

The debate’s format helped “save Trump from some of his worst impulses,” said David Greenberg, professor of history and of journalism and media studies at Rutgers University, and may have helped the Republican candidate appeal to voters who have been put off by his interruptions in previous debates.

“The producers of debates often forget that the main thing viewers want at a debate is to hear what the candidates have to say,” said Jon Klein, co-founder of Hang Media and the former president of CNN US “They don’t want to see a fight or performance. The mute button went a long way.”

The experts agreed with CNN’s decision not to have moderators fact-check the candidates during the debate, instead providing a fact-check on its websites and after the debate.

“There were a ton of inaccuracies that were left hanging but it would have been a mess to fact check the debate in real time,” Sesno said.

CNN provided a feed of its production to other networks and digital outlets, requiring them to use CNN in the programming title and keeping the CNN logo on screen throughout the debate.

The debate ratings figure reflects viewers across 16 networks, including CNN, Fox News and MSNBC.

CNN said that the match-up was its biggest debate ever across its websites, mobile apps and YouTube player.

The next Biden-Trump debate is scheduled to take place on Sept. 10, hosted by ABC News.