Let’s talk seriously about this.

Old age used to be synonymous with decrepitude. Modern medicine has changed that. Eighty is the new sixty.

President Biden, at 81, does show his age, bereft of the verve and vigor of youth. Yet there’s compensatory value in the experience and wisdom that comes with age. I often disagree with what Biden does, but it’s not like he doesn’t know what he’s doing. By all accounts he’s navigating the presidency with a clear-eyed steady hand, fully on top of things, taking in advice, making decisions based on sound and careful consideration.

Much in contrast with Trump’s shambolic feckless presidency. He’s actually only 3-1/2 years younger, but with overall physical health surely poorer. He’s clinically obese, eats junk, and doesn’t exercise, none of which is true of Biden. Mental health is another matter; we’ll get to that.

Plenty of leaders have functioned at high levels well into their late years. I remember how ably Konrad Adenauer (“Der Alte”) led West Germany till retiring at 87. At 88, Enrico Dandolo masterminded the Venetian conquest of Constantinople (and he was blind too). For what it’s worth, I’m 76 and feel no decline in mental acuity, but growth in knowledge and wisdom.

I’d have advised Biden to step down, making way for a younger and probably more electable candidate. Biden has accomplished a lot; a second term would more likely mar that record than further burnish it. Not to mention possibly losing the election. Quit while you’re ahead, man.

But he’s running, that’s that, and that makes our choice.

The “old man” comments in the recent special counsel report, by a former Trump appointee, exonerating Biden regarding classified documents, gratuitously echoed silly MAGA efforts to demean the President. In his subsequent press conference, Biden did embarrassingly say “Mexico” when he meant Egypt. An understandably human slip of the tongue and surely no big deal. Compare Trump at a rally repeatedly — repeatedly — saying “Nikki Haley, Nikki Haley, Nikki Haley,” when what he was talking about pertained instead to Nancy Pelosi. It actually seems he had the two confused in his messed-up head.

But it gets worse. Because he was blaming Pelosi for the January 6 violence, which is preposterous. More so in regard to Haley! And yet more so considering Trump’s own responsibility for that violence (part of his plot to steal the election).

This is far from the only instance of Trump behaving in a manner described widely now as “unhinged.” Another is his recently encouraging Russia to attack NATO countries not spending enough on defense. Such mental derangement has actually long been evident, and it’s worsening. He’s an unraveling psycho.

Again the contrast with Biden could not be more stark. Biden is sane. He’s responsible; conscientious; and acts in the public interest as he sees it. He’s full of human decency, compassion, empathy. Even if Biden were a senile doddering old fool (he’s not), I’d choose that over Trump, who makes plain he cares nothing about anyone but himself. Literally a textbook case of psychotic narcissism. And moreover in service to corrupt, evil purposes.

Is that the kind of president we want? Seriously? How can anyone even think of voting for that depraved monster?