In a 2018 speech to the Veterans of Foreign Wars, Trump said, “And just remember: What you’re seeing and what you’re reading is not what’s happening.” In other words, who are you going to believe—me or your lyin’ eyes?

“The man lies all the time,” writes Thomas Wells, an attorney once hired. In Bob Woodward’s book Fear, Trump’s former personal lawyer John Dowd describes the president as “a f******” liar,” telling Trump he would end up in an “orange jump suit” if he testified to special counsel Robert Mueller. And the former White House aide Anthony Scaramucci, when asked if he considers Trump a liar, admitted, “Okay, well we both know that he’s telling lies. So if you want me to say he’s a liar, I’m happy to say he’s a liar.” (In a later interview Scaramucci put it this way: “He’s an intentional liar. It’s very different from just being a liar-liar.”)

Trump is not simply a serial liar; he is attempting to murder the very idea of truth, which is even worse. “The point of modern propaganda isn’t only to misinform or push an agenda,” according to the Russian dissident and former world chess champion Garry Kasparov. “It is to exhaust your critical thinking, to annihilate truth.”

This is an urgent matter, and it makes this a dangerous moment because without truth and a common factual basis for our national life, a free society cannot operate.