Analysis by Chris Cillizza, CNN Editor-at-large

(CNN) -- On Wednesday morning, President Donald Trump sent out a tweet bashing the media. Nothing new there.

But, this tweet was different: Trump unintentionally revealed the false premise on which his relentless calls of "fake news" is based.

Here's the tweet:

"The Fake News is working overtime. Just reported that, despite the tremendous success we are having with the economy & all things else, 91% of the Network News about me is negative (Fake). Why do we work so hard in working with the media when it is corrupt? Take away credentials?"

Put aside the authoritarian -- but ultimately empty -- threat about taking away the media's "credentials," and focus instead on this sentence: "91% of the Network News about me is negative (Fake)."

Trump, I think, is referring to a 2017 study by the conservative Media Research Center which claimed that 91% of the nightly news coverage on the president was negative.

But, that's not (really) the point here. The point can be summed up in these two words from Trump: "negative (Fake)."

To Trump, those words mean the same thing. Negative news coverage is fake news. Fake news is negative news coverage.

This is, of course, not true. Negative news coverage -- or, seen more accurately through the Trump lens, media coverage that he feels is not sufficiently favorable to him -- is not, by definition, fake. Fake news is made-up news. It's not based in traditional reporting values like facts and sourcing. It's not "news" at all.

(Sidebar: The media -- me included -- does make mistakes. We're human. When it happens, we publicly correct the record. Trump seizes on those mistakes as incontrovertible evidence that the media is hopelessly fake. That would be like saying a person who got into one accident in 25 years of driving was a terrible and dangerous driver -- a drastic overstatement designed to score points with people already primed to believe the exaggeration.)

Trump either doesn't understand or ignores the difference between a story he doesn't like and one that is not true. He conflates the two for his own political purposes -- knowing his base hates the media and is more than ready to believe that journalists are willing to make up stories just to make Trump look bad.

Time and time again, Trump's claims about "fake news" have been debunked. What he calls fake news isn't fake at all. It's true -- he just doesn't like to read about it because it paints him as fallible, and he hates that.

Here's how Factcheck.org, a nonpartisan fact-checking operation at the Annenberg Public Policy Center, described Trump's approach to "fake news" in a detailed debunking of the idea headlined "Trump's Phony 'Fake News' Claims":

President Donald Trump often dismisses news stories or media outlets that he doesn't like as "fake news." How often? A database of his public remarks contains 320 references last year to "fake news."

Usually, it's a general complaint about news coverage — such as his Christmas Eve tweet: "The Fake News refuses to talk about how Big and how Strong our BASE is."

But there are times, too, when he has labeled accurate news reporting as "fake news" or spread false information himself, while at the same time accusing the media of being "fake" or "dishonest."

Here's the problem: Trump's attacks on the media -- as flawed and dishonest as they are -- are working. More than 4 in 10 people in a Gallup poll earlier this year could not name a single objective news source. Almost eight in 10 (77%) in a Monmouth University poll released last month said TV and print media report "fake news." That's a 14-point bump from the number of people who said the same last year.

The media is not blameless in all of this. As I noted above, we do make mistakes. We have made major strides in transparency but need to do even more to show our work to people. The more open we are about how we do our jobs, the better chance we have of convincing people that our most basic commitment is to getting stories right, not pushing some sort of imagined ideological agenda.

But, it's also important for people to understand what's behind Trump's aggressive anti-media campaign. Trump is about Trump. He calls media "fake news" because the coverage of him isn't as positive as he would like.

Try this experiment going forward. Every time Trump says or tweets the words "fake news," sub in the words "bad for me." It's revealing. Enlightening. And true.