 Doubts about Mr. Biden's age and acuity are widespread and growing. A majority of every demographic, geographic, and ideological group in the poll, including black voters and those who say they will still be voting for him, believe that Mr. Biden, 81, is too old to be effective. Seventy-four percent of voters view him as too old for the job, up five percentage points since the debate. Concerns about Mr. Biden's age have spiked eight percentage points among Democrats in the week since the debate to 59%.