Washington (CNN) On a sleepy Saturday morning back in March, Donald Trump dropped this bombshell on the political world: "Terrible! Just found out that Obama had my "wires tapped" in Trump Tower just before the victory. Nothing found. This is McCarthyism!"

Turns out, he was lying.

That's the conclusion the Justice Department reached Friday night in a court filing ; "Both FBI and NSD (National Security Division) confirm that they have no records related to wiretaps as described by the March 4, 2017 tweets," the filing read.

This affirms what former FBI Director James Comey told Congress about Trump's allegations in the spring and what former Director of National Intelligence James Clapper has repeatedly said as well.

Trump, for his part, has offered zero evidence to back up his initial claim because, as we now know conclusively, there was no evidence.

To sum up: The current President of the United States flat-out lied about the then-sitting president issuing a wiretap of his campaign headquarters.

It's easy to gloss over this. After all, from almost the moment Trump tweeted out the allegation, there was a very strong sense that it wasn't true. Comey's congressional testimony, coupled with Clapper's assertions -- and the fact that not a single person in a position to know said the wiretap was even a possibility -- made clear that the burden of proof was on Trump.

And, as the months passed and neither Trump nor his White House offered up even a shred of proof of his claim, it became increasingly hard to believe there was any there there on this.

Then there is the fact that Trump has demonstrated -- in his campaign and now in the White House -- a tendency to stretch the facts (and sometimes outright lie) to fit his purposes. In his first seven months in office, Trump made more than 1,000 totally false or generally misleading claims, according to The Washington Post's Fact-Checker site . During the campaign, 59 of the 92 Trump statements the Post's Fact-Checker checker were given four Pinocchios -- meaning that they were totally false. That's 64%.

People knew Trump wasn't terribly honest. In the 2016 exit poll , 64% said he wasn't "honest and trustworthy." (Amazingly, one in five people who said Trump was dishonest voted for him!)

Amid all that untruth there's a tendency to get numb to it. Trump says lot of things. Many of them aren't true. What are you going to do?

I understand that sentiment. We all become inured to things that once would have shocked us if those things happen on a daily basis. We couldn't survive if we were shocked by the same thing every damn day.

And yet! Let me reiterate what Trump did here: The current President of the United States flat-out lied about the then sitting president issuing a wiretap of his campaign headquarters.

That's a BIG deal.

What Trump is trying to do with the White House is exactly what he did in his career in real estate. Establish an alternative set of facts ( with apologies to Kellyanne Conway ) and then, by repeating them enough, convince people that his facts are just as good as the actual facts.

But, facts are facts. And, if Trump is allowed to cavalierly make false assertions like Obama wiretapped Trump Tower, then facts lose all meaning.

"When enough people make false promises, words stop meaning anything," said Jon Snow in the Season 7 finale of "Game of Thrones." "Then there are no more answers, only better and better lies, and lies won't help us in this fight."

Jon is a fictional character. But every word in that quote is truth.