(Jabin Botsford/The Washington Post)

You can’t trust the media, according to President Trump — unless the media happens to tell you that many people don’t trust the media. In that case, you can trust that the media is reporting trustworthy information about the public’s distrust of the media.

It makes sense, if you don’t think about it.

Trump claimed in a tweet Sunday that almost half of Americans believe major news outlets fabricate reports about him. He didn’t cite his source, perhaps because it was Politico, which he has consistently called unreliable.

“Unreliable” is putting it mildly. The president’s exact language about Politico is “the dumbest and most slanted of the political sites” — a “phony,” “third-rate,” “dishonest” “scam” published by “losers,” “clowns,” “serious haters” and “some very untalented reporters.”

Trump’s position is clear: Don’t believe Politico.

Except this time! Believe Politico when it says that 46 percent of Americans think that major news outlets (like, say, Politico) make things up.

Actually, this is not the only exception.

Great article,” Trump tweeted when Politico ran a story under a headline that said he “has a point” about political correctness. He has tweeted links to Politico reports on such subjects as praise he received from Sarah Palin, his vision of peace in the Middle East and Sean Hannity’s strong ratings.

Trump does not rate news outlets by fairness or accuracy. He evaluates individual reports by one standard alone: favorability.

There is no such thing as an outlet Trump recognizes as so consistently credible that he will accept criticism in its coverage — not even Fox News. Recall that during the Republican primaries, he said the network should be “ashamed,” characterized its debate moderators as “not very good or professional,” claimed that “other networks seem to treat me so much better” and briefly refused to appear on Fox News because it “has been treating me very unfairly.”

As far as Trump is concerned, negative equals fake, and positive equals real. It’s as simple as that. He has explicitly said that “any negative polls are fake news.”

The polling firm commissioned by Politico, Morning Consult, is a relatively new company that uses opt-in online survey companies to recruit samples that align with census demographics, rather than drawing random samples of the population. Morning Consult has a limited track record in elections but accurately estimated Hillary Clinton’s popular-vote win in 2016.

Credentials and methodology don’t matter to Trump. He has told the public over and over that Politico cannot be trusted. But now that Politico has published a poll indicating that such attacks on the press have been effective, Trump says the survey is legit.