In the first debate of the 2024 race, President Biden hoped to make the case that Donald J. Trump was unfit to return to the White House. Instead, Mr. Biden’s weak performance deepened doubts about his own fitness for the job.Astead W. Herndon, who covers politics for The Times, explains what happened.Guest: Astead W. Herndon, a national politics reporter for The New York Times and the host of the politics podcast “The Run-Up.”Background reading: President Biden’s shaky, halting debate performance has Democrats talking about replacing him on the ticket.Here are six takeaways from 2024’s first presidential debate.For more information on today’s episode, visit nytimes.com/thedaily. Transcripts of each episode will be made available by the next workday.