As long as I’ve covered Republican campaigns, there has been racial fearmongering: Dark-skinned people are coming to hurt you. Be very afraid.

With Reagan, it was “welfare queens” glomming onto tax-free cash income.

With George H.W. Bush, it was Willie Horton. Liberals would give more criminals like Horton furloughs, so they could break into your house and rape your girlfriend.

With George W. Bush and Dick Cheney, it was Arab terrorists. Democrats would let them invade America and kill us.

With Donald Trump, it was migrants swarming over the border from Central and South America with the intent to rape and kill, as well as the racist “birther” conspiracy about “Barack HUSSEIN Obama.”

Trump, who adopted his father’s view that some bloodlines are “superior” to others, has slipped into the usual Republican race-baiting by purposely fumbling Kamala Harris’s name, mispronouncing it different ways and christening her “Kamabla.”

Speaking to a group of Black journalists recently, Trump stunningly questioned Harris’s racial identity, saying, “She was always of Indian heritage,” and adding, “I didn’t know she was Black until a number of years ago, when she happened to turn Black.”

Turn Black? What does that even mean? Trump is a blend of Scottish and German, and no one says he “turned” German, even when he obsesses over bloodlines.

He is clearly befuddled by someone with brown skin who has come not to hurt Americans, but to save them from Donald Trump; someone who is not scary, as he is, but joyful, not threatening but thrilling.

And, in Trump’s worst nightmare, this dark-skinned someone is attracting huge adoring, dancing, laughing crowds.

From the first time I went on an exploratory political trip with Trump in 1999, he has measured his worth in numbers. His is not an examined life but a quantified life.

When I asked him why he thought he could run for president, he cited his ratings on “Larry King Live.” He was at his most animated reeling off his ratings, like Faye Dunaway in “Network,” orgasmically reciting how well her shows were doing.

He pronounced himself better than other candidates because of numbers: the number of men who desired his then-girlfriend, Melania Knauss; the number of zoning changes he had maneuvered to get; the number of stories he stacked on his building near the U.N.; the number of times he was mentioned in a Palm Beach newspaper.

By his mode of valuation, if his numbers aren’t better than his rivals’, he’s worthless.

That’s why Trump is always obsessing on his crowd numbers and accusing the press of lowballing head counts.

And that’s why he couldn’t admit he lost the election. If Joe Biden put more numbers on the board, Trump was worthless. The master huckster’s whole identity revolves around having higher numbers, even if they’re fake. (He always pretended his skyscrapers had more stories than they did.)

So, of course, seeing Kamala’s crowds and polls soaring drives him nuts.

When The Times’s Maggie Haberman asked Trump, at his news conference on Thursday, whether, given the riot on Jan. 6, he felt that there had been a peaceful transfer of power, Trump bizarrely veered off, averring that his speech that day on the Mall drew more people than Martin Luther King Jr.’s “I Have a Dream” speech.

Trump was like a blender going at full speed with the top off, goop splattering everywhere. He told a story about almost crashing in a helicopter with Willie Brown, who, according to Trump, said “terrible things” about Kamala, his onetime protégé. Brown, 90, said that he was never on such a helicopter ride. Nate Holden, 95, a former Los Angeles city councilman and state senator, said Trump might have been mixing up two Black politicians from California, since Holden said he was on such a flight with Trump in 1990.

Also, the ebullient Brown happens to really like his former inamorata, Harris; he has told people that she is “a special lady” and that, for a few years, in the period after he was elected mayor of San Francisco, they had wonderful times in Hollywood and Paris. Brown said Donald Trump did send his plane to bring them to New York to get Brown’s advice on a Los Angeles real estate deal. Trump was still “fun” then, Brown said, and Trump contributed to Harris’s attorney general campaign.

Just as when Trump claimed Trump Tower had New York’s “best” rolls, everything is about the best and the worst. “Tim Walz will unleash hell on Earth!” he pronounced in a Manichaean fund-raising email, painting as Lucifer a guy who, as David Axelrod put it, evokes Norman Rockwell.

A panicked Trump has been attacking Kamala as dumb. Whatever else you want to say about Harris, she is not dumb. Navigating tricky terrain, she has had one of the smartest takeoffs in political history. She looks comfortable and confident. He looks uncomfortable and rattled.

The gold-plated nepo-baby seethes at having to face Harris, whining that Democrats’ hot swap was “unconstitutional.”

So he finally cares about the Constitution?