AMES, Iowa—Bernie Sanders’s recent heart attack and hospitalization are bringing to the forefront an issue the Democratic party’s three leading presidential candidates have actively tried to minimize: their age.
At 78, the Vermont senator is the oldest in the party’s field. Former Vice President Joe Biden is 76, and Massachusetts Sen. Elizabeth Warren is 70. All three—who have consistently occupied the trio of top slots in public polls of the Democratic contest—are much older than the median age of about 55 years for a U.S….
