File this in the already-knew-it-but-can’t-believe-he-said-it category: Donald Trump doesn’t fact-check his tweets.

On Fox News Channel on Monday night, “O’Reilly Factor” host Bill O’Reilly called out the Republican presidential candidate for a bunch of bogus homicide statistics he retweeted over the weekend. The stats, which grossly inflated the rate at which black people kill white people, have been thoroughly debunked and widely labeled as race baiting.

Trump, in a moment of stunning candor, broke from the strategy he typically deploys when confronted with one of his inaccuracies — attack the media and insist that he is, despite seemingly insurmountable evidence to the contrary, correct. This time, he admitted that he hadn’t done his homework.

Here’s the full exchange with O’Reilly:

O’Reilly: This bothered me, I gotta tell ya. You tweeted out that whites killed by blacks — these are statistics you picked out from somewhere — at a rate of 81 percent. And that’s totally wrong. Whites killed by blacks is 15 percent, yet you tweeted it was 81 percent. Now …

Trump: Bill, I didn’t tweet, I retweeted somebody that was supposedly an expert, and it was also a radio show.

O’Reilly: Yeah, but you don’t wanna be. … Why do you want to be in that zone?

Trump: Hey, Bill, Bill, am I gonna check every statistic? I get millions and millions of people, @RealDonaldTrump, by the way.

O’Reilly: You gotta, you’re a presidential contender, you gotta check ’em.

Trump: I have millions of people. You know what? Fine. But this came out of radio shows and everything else.

O’Reilly: Oh, come on, radio shows?

Trump: Excuse me. All it was, was a retweet.

There are two significant takeaways here. One is sort of funny; the other, not so much.

On the funny side, it’s ironic that a presidential candidate who spends so much time blasting the media for alleged factual deficiencies would acknowledge that he doesn’t even try to verify information before spreading it to his 5 million followers.

Trying matters. We sometimes enforce an unreasonable standard of perfection when leveling charges of hypocrisy, as if reporters and politicians are disqualified from criticizing one another’s mistakes because they’ve all made errors of their own. That’s silly. How is anyone supposed to hold anyone else accountable for anything under that standard?

But if journalists and candidates are going to be checking up on one another, we all need to making a good-faith effort to get things right in the first place. Trump isn’t.

The Fix's Chris Cillizza explains why a "fact-free campaign" and a controversial comment on the Sept. 11, 2001 attacks won't hurt Republican presidential candidate Donald Trump. (Sarah Parnass/The Washington Post)

Which brings me to the not-funny takeaway: The double-digit front-runner for the Republican presidential nomination actually confessed to not caring about facts — at least as they relate to what he sends out to the millions of people who follow him on Twitter. (I get that retweets are not endorsements. But are retweets also not factual?)

At The Fix, we’ve already told you that Trump is leading a fact-free campaign, a conclusion shared by many other impartial observers and, obviously, Trump detractors. But we’ve also told you that he and his backers almost always have an alternate explanation for the things he says and does, which — however great a stretch those explanations might be — at least permits everyone living in Trumpland to say everyone else is wrong.

Trump, for an instant, anyway, stopped pretending Monday night.

So, when liberal cousin Bob says at the Thanksgiving dinner table that Trump recklessly spreads false information to stir things up, even the biggest Trump lover will have no comeback. The candidate himself said he can’t be bothered to check for truth before he clicks “retweet.”