Joe Biden is 77 and ought to actually remember when President Harry S. Truman popularized: "if you can't stand the heat, get out of the kitchen."

His wretched performance in an encounter with an Iowa voter who challenged him, melting down and flying off the handle, tells voters he never absorbed that political lesson.  Either he's either stupid or he has trouble remembering things.

Here's how the New York Times reported it:

NEW HAMPTON, Iowa — Former Vice President Joseph R. Biden Jr. on Thursday angrily lashed out at a voter who questioned his son's overseas business dealings at a campaign stop in Iowa, calling the man a "damn liar" in an unusually heated exchange.

The man — who declined to identify himself to reporters — falsely claimed that Mr. Biden had "sent" his son to work in Ukraine and accused him of "selling access to the president."

"You're a damn liar, man," Mr. Biden shot back. "That's not true. And no one has ever said that. No one has proved that."

Other than the Times' editorial insertion of the word "falsely," it's a pretty strong picture of a man who can't take it.

Image credit: Twitter screen shot.

The former vice president is obviously having problems with handling challenges, something any experienced pol can do with ease.  Instead of telling the farmer he's got it wrong, he growls with ad hominem attacks — "You're a damn liar" — and then attacks the man three times for being fat, failing to answer his question.  He didn't answer because he has no answer. 

Elizabeth Warren, by contrast, had no problem cooing kindness to some oppositional black voters who didn't like her stance on charter schools, a hot-button issue for candidates, given that black voters are the angriest about it and Democrats are sunk if they don't win over black voters.  Warren may not have answered the question they presented, but she kept her cool, even if all she offered was pabulum.

Not Biden.  Not only did he reveal himself to be nasty and unpleasant, visibly snarling at the man for being fat and challenging him to a push-up contest, he inadvertently revealed that he's not capable of taking challenging questions.  

More than anything, it's a sign he's actually a smooth-handed courtier who's grown rich in public office and now defends that access to the Washington trough as more important than winning skeptical voters over.  To these voters, it's obvious he's been surrounded by court flatterers all his life, given that he's always been in politics and little else.  That would be one way of explaining why he's not up for someone who doesn't shower him with compliments.

How exactly is a guy like that, flying into a rage at an uncomfortable question, going to take on the master of public relations and televised quick shots, President Trump?  Biden's main argument to voters is that he can win.  Public meltdowns are not the behavior of a winner.

What his little scrap with the farmer really tells voters is that he can't win.  It certainly explains why he's polling fourth in Iowa these days and still doesn't have the endorsement of President Obama, the man he worked with as vice president for all of eight years.

Worse still, he came across as bullying, something that has sunk many a politician, including himself.  Remember how Bob Dole was characterized (somewhat unfairly) as mean?  Mean and mean-spirited go over like a lead balloon in politics.

It may be that Biden was trying to copy President Trump's fighting spirit in his attacks on the skeptical Iowa farmer.  If he did, he didn't get it right.  Several factors enable Trump to say ferocious things without losing voters.  Trump has a stellar sense of humor and a ready wit, an overweening sense of optimism, and a fun sense of hyperbole, and more than anything, he abides by an absolute refusal to insult the little guy among the voters. 

Biden flunks that on all fronts.  He now stands exposed from his Iowa meltdown as a bully, a liar, and guy who can't take even the pressure of running for high office, and is bound to keep sliding in polls.

Hey, Joe: Ask Kamala Harris how far it's possible to slide when you can't credibly explain anything to voters without losing your temper.

Good riddance when he's gone from the scene, which is becoming a more distinct possibility every time the voters get these kinds of up-close looks at him.