Professor Derek Muller, "No Country for Old Presidents" -- Wall Street Journal
Professor Derek T. Muller's article, "No Country for Old Presidents" has been published in the Wall Street Journal. The article notes that Biden or Bloomberg would be older at the end of his term than Nixon when he died and considers if there should be an upper age limit on the presidency.
Excerpt from "No Country for Old Presidents"
Mr. Trump was 70 in January 2017, the oldest president ever inaugurated for a first term. Elizabeth Warren (71 in January 2021), Joe Biden (78), Mr. Bloomberg (78) or Mr. Sanders (79) would beat that record. If he wins next year, Mr. Trump (74) would eclipse Ronald Reagan (73 in 1984) as the oldest man ever re-elected.
The complete article may be found here (subscription required)