Donald Trump speaks to Matt Lauer on Wednesday during the Commander-in-Chief Forum in New York. (Mike Segar/Reuters)

An entire industry cropped up to prevent Matt Lauer’s historic failure last night. In a session with Donald Trump as part of NBC News’s “Commander-in-Chief Forum,” Lauer omitted a thing or two. Here’s the exchange that has lit up the commentariat.

TRUMP: I happened to hear Hillary Clinton say that I was not against the war in Iraq. I was totally against the war in Iraq. From a — you can look at Esquire magazine from ’04. You can look at before that. And I was against the war in Iraq because I said it’s going to totally destabilize the Middle East, which it has. It has absolutely been a disastrous war, and by the way, perhaps almost as bad was the way Barack Obama got out. That was a disaster.

LAUER: People talk about you and commander-in-chief, and not just Secretary Clinton, but some of your Republican opponents in the primary season, and they wonder about your temperament. They say, does Donald Trump have the temperament to be commander-in-chief?
You said something recently that I found interesting. You admitted that sometimes in the heat of a debate or when you’re talking about a lot of issues you say things that you later regret. So can we afford that with a commander-in-chief — to have a commander-in-chief who says things that he later regrets?

Yes, the moderator just plowed ahead into the next question, failing even to point out that anything that Trump said in 2004 about the Iraq War would have been after it started. But he didn’t do even that.

In failing to set Trump straight, Lauer missed an entire fact-checking oeuvre. FactCheck.org found “no evidence” that Trump opposed the Iraq War before it started (which is the only meaningful time frame, of course). PolitiFact gave Trump’s statement that he was “loud and clear” in opposition to the Iraq War a “false” rating. The Washington Post accorded four Pinocchios to Trump’s fanciful claim that the White House of George W. Bush attempted to “silence” his opposition to the Iraq War. The Associated Press determined that “no record has been established that Trump issued a clarion call against the March 2003 invasion of Iraq before it happened.” BuzzFeed’s Andrew Kaczynski dug up comments from Trump on Howard Stern’s radio show in 2002 expressing support for the Iraq War. The Atlantic declared that Trump was “making it up” when it comes to this supposed opposition to the Iraq War. The New York Times knocked down Trump’s claim.

Heck, everyone knocked down the claim. Nor was the debunking isolated to a single week of the campaign — such that a poorly timed vacation by Lauer could explain his breakdown at last night’s event. Careful examinations of Trump’s lies on this front started at least as far back as the first Republican primary debate in Cleveland, when he attempted to draw a crucial distinction between himself and the rest of the Republican field: “In July of 2004, I came out strongly against the war with Iraq, because it was going to destabilize the Middle East. And I’m the only one on this stage that knew that and had the vision to say it. And that’s exactly what happened.” Of course, the Iraq War started in March 2003, as folks pointed out at the time. BuzzFeed’s dogged Internet sleuth Kaczynski stayed on the story, writing in September 2015 that there was simply “no record” of prewar opposition.

The issue kept popping up, thanks to Trump himself. At a Feb. 13 debate, for example, he said, “I said it loud and clear, ‘You’ll destabilize the Middle East.’” Fact-checkers again got busy. Another instance surfaced in July, as Trump told supporters at an Indiana rally, “I didn’t want to go from the beginning, and I have proof — from the beginning. I didn’t want Iraq. I said you’re going to destabilize the Middle East, and that’s exactly what happened.” The Los Angeles Times sounded almost weary of unearthing the same fossil refutations: “Trump sticks to false statement that he opposed Iraq war from the start,” read the headline of the newspaper’s write-up.

And the Erik Wemple Blog has cited only a fraction of the fact-checking record on this Trump whopper.

Yet at least abridging the breadth of the corrective backlash is critical to appreciating just how completely Lauer whiffed in this particular instance. The whole I-was-opposed-to-the-Iraq-War claim by Trump is a core example of the candidate’s propensity to tell lies, or at least to brandish a reckless disregard for the truth. One needn’t have been paying terribly close attention to campaign coverage to be aware of this persistent revisionism. Fact-checks are designed in part to assist anchors who sit before presidential candidates.

What they’re not designed to do is to transform mendacious candidates into honest ones. That’s an impossible task; politicians have always lied and will continue lying, FactCheck.org, PolitiFact, The Washington Post’s Fact Checker and many others notwithstanding. This is a tradition to which Donald Trump appears particularly committed.