The fundamental offense of the Covington Catholic high-school kids wasn’t so much allegedly mobbing, mocking or getting in the face of an American Indian drummer at the Lincoln Memorial.

It was wearing red Make American Great Again hats. That was the actual, incontestable conduct that created the predicate for the presumption of guilt and all the rest of the grief they’ve been subjected to since.

For much of progressive America, if you are wearing the hat, you are suiting up for Team Racist. You are marking yourself out as a bigot and a goon. Your individuality doesn’t matter anymore, only the cap.

The entire Covington incident might have played out differently if the kids had been wearing red Washington Nationals caps. The imbroglio might not have gotten any attention at all. Even if it did, progressives taking a critical view of the students might have been more inclined to view them as immature teenagers rather than totems of hate.

As an analysis at Vox noted of the Covington incident, “The hats extinguished pretty much any benefit of the doubt a liberal observer might have given these kids.”

Exactly.

Alyssa Milano notoriously tweeted, “The red MAGA hat is the new white hood.” Which would be close to an apt analogy if people donned MAGA hats to carry out hideously violent crimes against African-Americans and other people uncongenial to them.

In a similar vein, TV writer and producer David Simon pronounced, “Once a campaign prop, a MAGA cap now fronts for such raw evil.” He makes it sound like a red baseball cap with an embroidered American political slogan on the front is the equivalent of the totenkopf.

This is, to put it mildly, an uncharitable view of their fellow citizens, who voted by the tens of millions for the guy who invented the red cap.

It speaks to the marketing genius of Donald Trump that he managed to create not just a potent piece of campaign memorabilia, but a cultural marker that will forever be associated with this period of our national life.

The MAGA hat denotes support for him, yes, but also a certain boldness and unwillingness to be bullied that isn’t merely symbolic — people occasionally get assaulted for doing nothing other than wearing the caps.

And why not, if the cap symbolizes only one thing for the left? As Commonweal magazine columnist Mollie O’Reilly wrote of the Covington controversy, “You don’t let your kid wear a MAGA hat and then act offended when they get taken for a racist.”

Well, there’s the minor detail that your kid might not be remotely racist. It should be incumbent on adults to realize, much though they hate Donald Trump, that not everyone who supports him or wears his political paraphernalia is a hater.

But it is the adults who take the childishly reductive view of this question. When Jamie Lee Curtis regretted her snap condemnation of the students, journalist Victoria Brownworth tweeted at the actress her disappointment: “DID YOU MISS THE MAGA HATS?”

This is why very little outrage has been directed at the venomous, freakishly anti-gay, openly racist Black Hebrews who berated and taunted the students. They weren’t wearing MAGA hats.

And this is why much of the left didn’t want to relent in the campaign against the students, even after exculpatory video emerged. It wasn’t just that many progressives still took a hostile view of events, they knew for a fact that the kids — at least some of them — had worn MAGA caps. And what else was there to know?

For them, this rendered the Covington students simply political and social symbols to be crushed underfoot.

Never mind that each of them was a teenage kid who — even if you think he has bad taste or noxious political views now — has a lifetime ahead of him to grow and change.

They wore the hats, and can never be forgiven.

Twitter: @RichLowry