Whatever their differences, the two front-runners in the Democratic presidential race, Joe Biden, born Nov. 20, 1942, and Bernie Sanders, born Sept. 8, 1941, share one common trait: They are too old to be president.
Biden, leading the RealClearPolitics average of polls, will be 78 years old on Inauguration Day 2021. Sanders, No. 2 in the field, will be 79. Both would be older upon taking office tha…
