Thursday morning, after hearing that Donald Trump got huffy with Justin Trudeau over Canada “burning down” the White House in the War of 1812, I sent out a tweet noting that in fact we, the United States, invaded Canada during that war; we even burned down government buildings in Toronto (then called York). As usual, what Trump said to Trudeau was not only not the truth, but turned reality inside out and ran it through the pulverizer.

One of my regular correspondents replied that Trump may have been confused by “this,” followed by the trailer for Canadian Bacon, the 1995 John Candy movie in which an unpopular president starts a war with Canada to raise his approval numbers.

I started laughing, but stopped when it hit me that with Trump, anything’s possible. Check that—it’s not possible that he read a history book. It also seems unlikely that he would have watched a serious movie that tried hard to get things right, such as Lincoln, which would bore him to tears within a half an hour. On the other hand, that episode of All in the Family where Archie tells Meathead the “truth” about the causes of the Depression—now that’s more like it for Trump source material.

Conservative readers are saying right now, “there you go again, you snooty liberals, you and your book-learnin’.” All right, sure. There’s no doubt that it’s a liberal reflex to sometimes make fun of conservatives for not knowing things. And yeah, some liberals do that in a superior and supercilious tone.

But what’s happened in this country over the last, oh, 40 years or so is that in our political discourse, it has become far, far worse to make fun of someone for not knowing some basic historical fact than it is to not know the fact. And that is absurd.

I’m sorry. By which I mean, I’m not remotely sorry: It is worse—plainly and unambiguously worse—to be ignorant of basic history than it is to know that history and be a little insufferable about knowing it. A civilization that has concluded that the latter is worse is a civilization that is valuing attitude and posture over fact, and that is precisely the corkscrewed value system that gave us a cretin like Trump in the first place.

When the conservative counter-offensive really kicked in, back in the 1970s, conservatives who wanted to dramatically remake and reorder American society knew they had a big job in front of them. All kinds of presumptions about how life and society worked were lodged deep in people’s minds. Many—most, indeed perhaps nearly all—of those assumptions were kind of liberal. The Republicans caused the Depression. Roosevelt saved the country. Unions helped us prosper in the postwar era. Science was noble, and experts were to be venerated. Religion was to remain private. The generals got us into an unwinnable war in Vietnam. And so on.

These were all things that the broad majority of Americans believed. They were also, well, you know, true. Republicans did wreck the country in 1929, FDR did save it, experts had expertise that was of value. Conservatives had to get Americans to un-believe all that—to hate unions and mistrust experts, to agree that liberals lost the Vietnam War.

That effort involved two prongs. The first and more obvious was inventing their own set of “facts” whereby, say, Roosevelt prolonged the Depression. The second prong was the discrediting of those who continued to trumpet the old liberal version of reality, and the sharpest knife in that drawer was by far the charge of elitism.

Once Republicans figured that out, the discrediting got simple. All you had to do to puncture someone’s argument was call that person an elitist. It often didn’t matter whether that someone was factually correct. In fact, being factually correct was all the more damning! Knowing the difference, say, between the Lippmann and Dewey points of view was evidence itself that one was too dependent on exterior knowledge, had no internal instincts on which to operate and base decisions.

Well, 40 years later, here we are. We finally have a president of the United States who is all gut, no knowledge. There are consequences to this. Our allies don’t like us. We’re starting trade wars with them that are ahistorical and ungrounded in fact. Trump’s going to Canada today for a G-7 meeting he has no desire to attend and where not much of anyone wants to see him. On the apparently upcoming North Korea meeting, Trump said Thursday, “I don't think I have to prepare very much.”

Of course, instinct works sometimes. Trump may connect with Kim Jong Un—in fact, one might say they’re likely to, as they seem to be about the same emotional age. But instinct fails, too. And when it does, look out. Stalin’s instinct was that he could trust Hitler.

So laugh when Trump blurts out some historical whopper. God knows we all need to laugh. But remember too—the fact that a man that ignorant is our president is the culmination (I hope, anyway) of a long attack on truth set in motion four decades ago that persuaded millions of Americans that knowledge is slavery and ignorance is indeed bliss.