Washington (CNN) Well, that was fast.

In less than a day, the average age of the candidates vying for the White House jumped by some seven years, from about 68 to 75.

It's perhaps more striking to see this sort of gerontocracy on the left. For more than half a century, Democratic presidential bids have stood out for their promise of something or someone new: John F. Kennedy (43) in the 1960s, Bill Clinton (46) in the '90s, Barack Obama (47) in the '00s. (In 2017, at 70 years old, Trump became the oldest president to be inaugurated.)

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