Sarah Palin is a fraud with charisma — and enough political support to effectively hold the Republican Party hostage. She is ridiculous and dangerous in equal measure.

Palin is certain about everything and knows about nothing. The only true facts are those she recognizes; other facts, when cited to contradict her private truth, are deemed politically motivated. History books are nothing more than weapons used by her enemies in their incessant attacks, their pitiful attempts to play “gotcha.”

In her view, she does not make mistakes. Therefore, it may surprise you to learn, this is who Paul Revere was:

“He who warned the British that they weren’t going to be taking away our arms, by ringing those bells, and making sure as he’s riding his horse through town to send those warning shots and bells that we were going to be secure and we were going to be free.”

Utter, complete nonsense. The purpose of Revere’s midnight ride was to warn townspeople and patriot leaders that British troops were approaching. He didn’t ring any bells or fire any warning shots; the prearranged signal involved hanging lanterns in the steeple of the Old North Church, one if the redcoats were approaching by land and two if by sea.

Palin gave her fanciful account Thursday after touring Boston’s historic North End. “We saw where Paul Revere hung out as a teenager, which was something new to learn,” she told reporters — neglecting to add, I guess, that she didn’t bother to read any of the brochures.

It was comical and weird, like a lot of Palin’s antics, but so what? Anybody can have a momentary lapse and say something dumb in front of a television camera. You laugh it off and move on.

Unless you’re Sarah Palin. She appeared on “Fox News Sunday,” and Chris Wallace asked the obvious question: “You realize that you messed up about Paul Revere, don’t you?” He must have expected her to be charmingly self-deprecating. Instead, to Wallace’s evident surprise, she insisted that her ridiculous account was correct.

Palin seized on a lesser-known incident during Revere’s ride, when he was captured and briefly held by several British soldiers. He bluffed his way out of his predicament by boasting that 500 well-armed militiamen were up ahead, ready for battle.

“Part of his ride was to warn the British that, ‘We’re already there,’ that, ‘Hey, you’re not going to succeed. You’re not going to take American arms. You are not going to beat our own well-armed persons, individual, private militia that we have.’ “

Wallace smiled as if he couldn’t quite believe what he was hearing.

“I didn’t mess up about Paul Revere,” Palin said. “I know my American history.”

Yes, you did. And no, you don’t.

Anyone who believes that Revere rang bells and fired warning shots simply isn’t going to know — until after the fact — about the encounter with the British soldiers. And in any event, Revere didn’t set out “to warn the British” — he was warning colonists about the British. And he wasn’t making some kind of Second Amendment statement about “American arms” because there was no Second Amendment. And …

Yes, I’m belaboring the obvious. But I’m doing so because the incident says so much about Palin’s arrogant disregard for objective fact. It’s never about the truth. It’s always about Sarah.

She told Fox that she was the victim of a “gotcha type of question.” But there is no indication, from video of the encounter, that she was asked specifically about Paul Revere. Her peroration came amid a general recounting of her visit to Boston.

The gaffe is understandable — well, almost understandable. But she doubled down with a claim of persecution and a bald-faced lie. That is what we ignore at our peril.

This is a small, unimportant matter. But Palin demands to be seen as a big, important person in the nation’s political life. Her party is so afraid of her that the putative front-runner for the presidential nomination, Mitt Romney, won’t even call her out for stealing thunder from his campaign kickoff by just happening to be in the neighborhood, complete with the attendant media circus.

The woman, like Lord Byron, is “mad, bad, and dangerous to know.” I’d shout it throughout the land, if I could find my horse and my bells.

Eugene Robinson’s e-mail address is eugenerobinson(at)washpost.com.