At his inauguration, Trump swore to “faithfully execute the office of president.” He violates that oath when he speaks to the nation in bad faith. Other presidents have lied — Lyndon B. Johnson about Vietnam, Richard M. Nixon about Watergate, Bill Clinton about Monica Lewinsky. But never have we had a president who lies about everything , who invents his own fake facts, who continues to trumpet patent falsehoods even when confronted with the actual facts.

AD

AD

And yes, undisputed facts do exist and can be ascertained. I am not talking about subtle matters of interpretation; I’m taking about knowing falsehoods, commonly known as lies.

Here is just one example: At a roundtable with a group of workers in Duluth, Minn., in June, Trump said, “The head of U.S. Steel called me the other day, and he said, ‘We’re opening up six major facilities and expanding facilities that have never been expanded.’ ” A few days later, at the White House, Trump said, “U.S. Steel just announced they’re expanding or building six new facilities.”

Reporters called the company for details and learned that U.S. Steel has not announced plans to open any new domestic steel mills, period. Not six new plants; not even one. The Post’s Fact Checker column gave Trump the maximum four Pinocchios for his patently untrue statement. End of story, right?

AD

AD

Wrong. More than a month later, at one of his campaign-style rallies, Trump declared that “U.S. Steel is opening up seven plants.” At another rally around the same time, he told supporters that “U.S. Steel just announced that they’re building six new steel mills.”

Six new plants, seven new plants, what’s the difference when neither is true and the real number is zero? In June, Trump’s claim might have been called a “misstatement” or a “falsehood” or an “untruth.” A month later, after the truth had been clearly established, that same claim could only be called a bald-faced lie.

And those are just a smattering of the more than 5,000 falsehoods from Trump that The Post has tallied since he took office. Trump clearly understands the benefit of flooding the zone. If, during the course of a rally or a news conference or an interview, he tells one glaring lie, that’s where all attention will be focused. But if he tells a dozen lies, or two dozen, it is all but impossible for critics to keep up. By the time all those lies have been called out, Trump will have spewed a few dozen more.

AD

AD

In an interview broadcast Sunday, “60 Minutes” correspondent Lesley Stahl offered a valuable lesson in how to pin Trump down. At one point, he was trying to leave the false impression that there is serious scientific debate about whether human activity has contributed to climate change. “They say that we had hurricanes that were far worse than what we just had with Michael,” Trump said.

“Who says that?” Stahl interjected. “ ‘They say?’ ”

“People say,” Trump responded. “People say . . .” Finally he claimed, without offering a shred of evidence, that “scientists . . . have a very big political agenda” — a dodge amounting to an admission that Trump had no factual basis for the claims he was making.

AD

When Stahl turned to Russia’s meddling in the 2016 election, and Trump said, “I think China meddled also,” Stahl again called him on it: “You are diverting the whole Russia thing. . . . You are, you are.”

AD

Trump finally got so flustered that he said, “Lesley, it’s okay. In the meantime, I’m president — and you’re not.”

And that is the point.

When Trump insists on his own invented “facts,” he makes reality-based political dialogue impossible. His utter disregard for truth is a subversion of our democracy and a dereliction of his duty as president. The founders considered themselves men of honor whose word was their bond. They left us the vague, encompassing phrase “high crimes and misdemeanors” for just such an emergency.

AD