Donald J. Trump Is the Oldest President to Take the Oath, Again

Before Joseph R. Biden Jr. was sworn in 2021, Donald J. Trump held the record for the country’s oldest commander in chief. He reclaimed the record on Monday.

How Biden’s Inner Circle Protected a Faltering President

“Your biggest issue is the perception of age,” Mike Donilon, the president’s longtime strategist, told him in 2022, according to people who heard him.