Jennifer Senior: Biden is old. That’s a good thing.

When Joe Biden is sworn in on Inauguration Day, he will be 78, the oldest president to take the oath of office since the birth of our Republic. No shortage of observers on both the left and the right have written about this historic curiosity, as often with frustration (the left) and contempt (the right) as they have with awe.I can’t be bothered with the despicable Sleepy-Joe canard that the right is peddling, except to say that if this is what dementia looks like, I don’t know what