Biden’s Lapses Are Said to Be Increasingly Common and Worrisome

In the weeks and months before President Biden’s politically devastating performance on the debate stage in Atlanta, several current and former officials and others who encountered him behind closed doors noticed that he increasingly appeared confused or listless, or would lose the thread of conversations.

Like many people his age, Mr. Biden, 81, has long experienced instances in which he mangled a sentence, forgot a name or mixed up a few facts, even though he could be sharp and engaged most of the time. But in interviews, people in the room with him more recently said that the lapses seemed to be growing more frequent, more pronounced and more worrisome.

The uncomfortable occurrences were not predictable, but seemed more likely when he was in a large crowd or tired after a particularly bruising schedule. In the 23 days leading up to the debate against former President Donald J. Trump, Mr. Biden jetted across the Atlantic Ocean twice for meetings with foreign leaders and then flew from Italy to California for a splashy fund-raiser, maintaining a grueling pace that exhausted even much younger aides.

Mr. Biden was drained enough from the back-to-back trips to Europe that his team cut his planned debate preparation by two days so he could rest at his house in Rehoboth Beach, Del., before joining advisers at Camp David for rehearsals. The preparations, which took place over six days, never started before 11 a.m. and Mr. Biden was given time for an afternoon nap each day, according to a person familiar with the process.

Andrew Bates, a White House spokesman, said on Tuesday that “the president was working well before” the 11 a.m. start time each day, after exercising. Still, at a fund-raiser on Tuesday evening, Mr. Biden blamed