I'd love to know why people keep bringing this up with Democrats and never Republicans. Nobody whined when Mitch McConnell or Jim Inhofe ran for another term, or how Grassley (the second-oldest member of the U.S. Senate) is being indecisive on whether or not he'll run again. Kind of like how people always say Feinstein's too old to serve, yet despite being only three months older than Grassley, nobody says the same of him. And trust me, I lived in Iowa for a long time and I never once heard anyone say Grassley was too old, outside of Democrats, of course.
Because this is a left-leaning forum, and people would be sadder if Leahy dies than McConnell.
I'm not just talking about this forum. I'm talking about people who discuss politics in general. I see it happen all the time.