If you happened to see pigs flying the other day, it’s because Robert F. Kennedy Jr. visited the New York Post to discuss his challenge to President Joe Biden for the ’24 Democratic nomination.

It’ll be a serious challenge, if the Democratic establishment and its media allies can’t quash him.

Kennedy has real conviction and charisma, and he’s fiercely independent of many of the party’s reigning pieties — all of which should appeal.

For example, he vows, “I would seal the border” as the current policy has created a “humanitarian deathtrap” and: “You can’t have a country if you can’t protect your borders.”

Yet he remains very much a man of the left, who would expand legal immigration.

He’s equally clear that wildly “printing money” (as both parties have been doing) creates “the illusion that there’s no cost to” massive federal spending but is, in the end, a gift to the rich and a bane on the middle and lower classes.

And that the nation’s COVID response entailed an “assault on constitutional rights” lacking “any kind of scientific citation or democratic process” — all backed by government censorship on social media. (A man of strong faith, he’s especially appalled that we shut down churches.)

Though not otherwise a fan, he even praises Gov. Ron DeSantis for standing up to the madness.

He gets something fundamental about Trump hysteria, too: “The worst thing he did was lockdowns. And nobody’s blaming him for that.”

Indeed, “the Democratic Party lost its way most acutely in reaction to” Trump, compulsively opposing everything he did. (He clearly sees Dems as viewing Dr. Anthony Fauci as the real lockdowner.)

He’s also the only Democrat we’ve heard (rightly) call the Durham report an “appalling” exposé of FBI malfeasance.

But these genuine insights come amidst a rapid-fire barrage of what can only be called conspiracy theories.

“Neocons” are responsible for America’s policy ills. “Pesticides, cellphones, ultrasound” could be driving an upswing in Tourette syndrome and peanut allergies.

And that’s to say nothing about his well-known, totally anti-science activism against vaccines (long predating COVID).

Yet his unique Greatest Hits megamix of tinfoil-hat thinking on everything from Big Pharma to the Ukraine war may well appeal to the Internet generation, which seems particularly prone to buying claims that this particular “they” is fully to blame for that particular woe.

After all, mainstream Democratic politicians now push plenty of nonsense, too: Corporate greed is the main driver of inflation; “white supremacy” has become one of the nation’s leading threats; children “belong to all of us” — meaning the state, and definitely not their parents.

Biden, in short, ignores Kennedy at his own peril.

Whether it’s the incumbent’s age or the disasters he’s wrought, most Democrats want another choice for 2024 — yet the party’s in the tank for Biden even more than it was for Hillary Clinton in 2016.

And plenty of Dem voters remember how that turned out.

They may not buy every one of Kennedy’s conspiracy theories, but it’s hardly a conspiracy theory that the border is open, prices continue to soar far faster than wages and the president simply refuses to admit such glaring facts.

RFK Jr. says his central message is “Tell the truth.”

And he’s already at 20% in the primary polls.

Expect that number to soar as long as he’s the only guy willing to stand up and point out that the emperor has no clothes.