Someone in the White House must really hate Joe Biden.

Who had the stupid idea to invite his charismatic predecessor back to upstage the president and humiliate him before the world?

If the idea was to borrow the Barack Obama magic, it backfired. The president just looked feeble and ­unpopular against his limelight-hogging former boss.

Invited back to the White House for the first time in five years, Obama began his speech Tuesday touting the 12th anniversary of his Affordable Care Act by referring to the president as “Vice President Biden.”

He quickly followed up with “That was a joke!” but the point was understood by everyone, that Joe is the beta in that relationship, even if he is the most powerful man on the planet.

What does that make Obama?

Well, he mentioned himself 33 times during his speech, according to Steve Guest, communications adviser for Sen. Ted Cruz. Obama sang his own praises as he rattled off a list of his presidency’s accomplishments.

There was little effort to burnish the battered reputation of the old man standing glumly alongside him trying to look jolly. Beside him, Vice President Kamala Harris was fairly bursting with excitement.

After the speech, the three luminaries mingled with the crowd, and that was where Obama showed his true colors.

In C-SPAN videos, you see Biden, quite cheery, glad-handing the crowd, Harris at his side, when suddenly, from stage left, emerges Obama, face creased into a handsome smile, eyeing the same group that Biden is schmoozing.

Vanishing smile

Harris senses Obama’s presence and whips around with a joyous expression, and they meet each other’s gaze for an instant. The smile vanishes from Biden’s face as Harris turns away. He spots Obama and a frown furrows his brow. ­Obama, by way of greeting Harris, tosses his head like a horse and she responds by hunching her shoulders like an excited kid. As a frowning Biden moves closer, she pirouettes to face him, looking faintly amused, her lips pursed in a sort of private “uh oh, lol.”

Biden’s face grows thunderous. He opens his mouth in a snarl, looking straight at the side of ­Obama’s head, and says something that sounds like: “It’s not my . . .” and then stops himself.

Obama ignores him and reaches into the little group of admirers before him, shaking hands and creasing his face into a handsome smile. At this stage, Harris has turned away from Biden and positioned herself between the two men, mirroring Obama’s charm pantomime.

Biden grimaces. Then he fixes his eyes on Obama. He reaches around Harris to touch Obama’s arm and attract his attention. Obama, smiling animatedly, ignores him, before maneuvering out of arm’s-length.

Biden scowls over his shoulder. Obama’s escape is foiled by a short, blond woman who lunges in to shake his hand. Biden looks stricken, staring at this woman who has eyes only for Obama and Harris at his side.

A few moments later, he makes his move. He thrusts out his left hand and places his long, white fingers on Obama’s right shoulder. You can tell Obama feels it, because he involuntarily jerks his head away, a micro-expression of what looks like disgust flitting across his face.

Biden is concentrating intently on his hand now gripping tightly onto Obama’s shoulder.

Obama’s eyes swivel in Biden’s direction but his head does not move. He lets go of the blond woman’s hand with a smile and leans away to shake off the hand now firmly attached to his shoulder. He and the blond woman start bantering. He laughs at something she says.

Biden looks desperate and disbelieving as he clings to the shoulder of a man pretending he doesn’t ­exist.

Obama drops his shoulder, but can’t shake off the hand. A shadow passes over his face — anger, maybe, or exasperation. He raises his right hand high in the air and then dips it down into the crowd to shake another hand. He swings and dips and leans forward but the bony, white hand clings on.

Harris, mouth agape in an approximation of ecstasy, stares up at Obama with glistening eyes.

Obama tries again to shake off the hand, raising his arm even higher in an exaggerated goodbye wave to his admirers. But Biden clings on.

No one to talk to

One of the video clips, posted on social media by the Republican National Committee’s research team with the caption “Literally no one wants to talk to Joe Biden,” ends right there.

But the entire C-SPAN video shows that in the next moment, ­Obama gives into the inevitable.

He swivels around to face Biden, and the hand finally lets go. He tosses his head slightly at the old man and raises his eyebrows as if to say, “What’s up?” As if he didn’t know.

Biden relaxes into a beaming smile, dignity restored, and finds a woman nearby for a courtly introduction to his ex-boss. Then Obama gestures lightly and moves off with Harris beside him, Biden trailing.

Another video showed Biden and Nancy Pelosi passing within inches of one another and avoiding eye contact. Biden walks in the other direction and raises both arms in a welcoming, “Look who’s here” gesture to nobody who is visible on camera, but appears to receive no response, so he turns back to where Pelosi had been and finds nothing but a golden curtain. His head turns and there, a few feet away, he sees Obama holding court, before eager acolytes.

No one notices Biden. He pauses before turning his back and walking away, shoulders slumped.

Rolling Stone and other Democratic operatives fanned out the next day to declare that the RNC’s video clips were maliciously edited and “taken out of context.”

But, sadly, they were not. You can watch the entire video from beginning to end and your sense of Biden’s abandonment by his party will not change.

With a haunting violin melody as soundtrack, the flags and young ­faces in military uniforms milling around in the background, there is something tragically iconic in that first video, in a way I think we can only dimly grasp today.

America’s adversaries will know exactly what to think when they see our forlorn, unloved president, wandering, neglected and ignored, around his own house, while his underlings fawn over his predecessor. Where were his staff to save him from humiliation? Where, for that matter, was Dr. Jill?

One thing is now clear: the VP is not a team player. If anything, Harris is actively working against the president and is in the secret thrall of Obama.

We also saw the true character of Obama. He is nothing but a Mean Girl, consumed with his own charms. What a piece of work! Would it have killed him to show a little grace and kindness to his floundering successor?

Humiliating the president of the United States publicly is wrong — even if it is Joe Biden.

In the end, maybe there was some 3D-chess genius in inviting Obama to the White House, because even Biden’s most ardent critics could not help but feel a twinge of sympathy for him.