Here's Biden's invitation to the voters, according to LifeZette:

When a reporter told Biden that voters he talked to were wondering if the former senator from Delaware had lost a step, Biden answered, “What do you think?”

When a reporter told Biden that voters he talked to were wondering if the former senator from Delaware had lost a step, Biden answered, “What do you think?”

When a reporter told Biden that voters he talked to were wondering if the former senator from Delaware had lost a step, Biden answered, “What do you think?”

“I say if they’re concerned, don’t vote for me,” Biden said while speaking to reporters in Keene, New Hampshire.

“I say if they’re concerned, don’t vote for me,” Biden said while speaking to reporters in Keene, New Hampshire.

“I say if they’re concerned, don’t vote for me,” Biden said while speaking to reporters in Keene, New Hampshire.

We didn't get to learn the conclusion to that one.

It happened as Biden threw out another string of gaffes, mixing up New Hampshire with Vermont, claiming the 1968 assassinations of Martin Luther King, Jr. and Robert Kennedy happened in the 1970s (shouldn't these years be 'seared' in anyone who remembers them's memory?), and a claim that this month's mass shootings happened in Houston and Michigan instead of Dayton and El Paso.

Things are so bad in fact, according to LifeZette that:

...the gaffes appeared to have raised enough concerns that allies of the former vice president reportedly suggested he scale back the number of events he did on the campaign trail. David Axelrod, a former adviser to then-President Barack Obama, blasted that advice, arguing this past Thursday that he shouldn’t be cloistered as a presidential candidate. “This is bad advice. You can’t cloister the candidate and win,” tweeted Axelrod, the chief strategist of Obama’s 2008 and 2012 campaigns. “He either can cut it or he can’t, and the only way he can prove he can is to be an active and vigorous candidate. He’s running for president of the United States, for God’s sake!”

Now he's throwing out an invitation to voters to not vote for him if they think he's too old and addled to be president. He could have argued that he is old and addled but still better than Trump as one way of assuaging the fears that are out there. But instead of that tack, he's taking the ego and entitlement route and telling people that if they vote for him, they can only be doing so because they think he's sound of mind, he won't permit it otherwise. He doesn't want the vote of anyone who might just think he's over the hill. The ego gratification here is apparently pretty important to him.

Yet it just so happens that Joe's state of mind is exactly what voters are worried about. According to Nate Silver's Five Thirty Eight, Biden's advanced age (he's 78 now) worries voters a lot more than his gaffes. So Biden's call to voters not vote for him on age grounds is exactly the kind of invitation that might just be taken up.

Recent history is replete with this kind of out-of-touch invitation-throwing ending up as an exploding cigar in the issuer's face.

Twenty years ago, then-Indonesian President B.J. Habibie, off the top of his head and thinking everyone adored him, issued an invitation to an independence referendum to East Timor, expecting an easy victory from the locals, and the United Nations off his back. Much to his surprise, the voters obliged, voting for independence by 78%.

Six years ago, then-U.K. Prime Minister David Cameron, expecting he'd get a better deal for Britain from the European Union, startled everyone by announcing a referendum on whether the U.K. should stay in the European Union at all. Much to his surprise, they didn't.

Three years ago, in Colombia, then-President Juan Manuel Santos, hankering after that Nobel peace prize, put forward a referendum to voters on whether to accept the sweet deal he had negotiated for FARC's Marxist narcoterrorists, who had terrorized his country for 50 years. He thought this was going to be an easy one. Much to his chagrin, they said hell no. He still got his peace prize and the Colombian voters got ignored, but that deal sure as heck deprived him of the ego gratification he longed for.

Which brings us back to Old Joe, inviting voters to not vote for him if they think he's nuts.

He's convinced he's got it in the bag, so now he wants the ego gratification of knowing for sure that voters are only voting for him because they're convinced he's all there.

It's not all that different from those other historic examples.

The Democratic presidential frontrunner should be careful for what he wishes for.