How Should a Voter Assess the Risk Posed by Aging Politicians?

How should we think about whether someone is too old to serve in office?

With the leading candidates for their parties’ presidential nominations aged 80 (Biden) and 77 (Trump), the question is on our minds. The recent freezing episodes of Mitch McConnell (81) have put it there too. Somewhere off in the background, the staff of Dianne Feinstein (90) is wheeling her into a Senate hearing that she may or may not show signs of understanding.