Rachel Maddow says someone tried to dupe her into airing a bogus scoop about collusion between President Trump's campaign and Russia, presumably intending to debunk the story later and tarnish Maddow's reputation in the process.

Having avoided the trap, the MSNBC host hopes to serve as a cautionary tale for others in the media.

“Heads up, everybody,” Maddow said on the air Thursday night. “Somebody for some reason appears to be shopping a fairly convincing fake NSA document that purports to directly implicate somebody from the Trump campaign in working with the Russians on their attack on the election. It is a forgery.”

She continued:

Whether or not the Trump campaign did it, one way to stab in the heart aggressive American reporting on that subject is to lay traps for American journalists who are reporting on it, trick news organizations into reporting what appears to be evidence of what happened, and then after the fact blow that reporting up.

You then hurt the credibility of that news organization. You also cast a shadow over any similar reporting in the future, whether or not it's true, right? Even if it's true, you plant a permanent question, a permanent asterisk, a permanent “who knows?” as to whether that too might be false, like that other story — whether that too might be based on fake evidence.

The phony document provided to Maddow is exactly the kind of thing that Columbia Journalism Review publisher Kyle Pope warned of, in May, when I asked him whether news outlets should be worried about making careless errors in their rush to advance the Trump-Russia story.

“I think the bigger risk right now is of somebody getting duped — intentional misdirection or fabricated leaks,” Pope told me. “In this climate, that is more what I would be worried about.”

Later that month, conservative radio host Bill Mitchell proposed “flooding the NYTimes and WAPO tip lines with all kinds of crazy 'leaks' ” to induce false reporting.

Maggie Haberman of the New York Times responded by tweeting that the Trump administration “has tried this a few times.”

Efforts to fool media companies into discrediting themselves are not limited to the national stage. Maine Gov. Paul LePage suggested in an interview with local radio station WGAN-AM on Thursday that he tries to plant false information in news reports to make the press look bad.

“I just love to sit in my office and make up ways so they’ll write these stupid stories because they are just so stupid,” LePage said.

It is a credit to Maddow's sense of fairness that she — as vocal a Trump critic as there is — exercised enough restraint and skepticism to sniff out an elaborate hoax that she might have wished were true. Maddow likely was targeted on the premise that she personifies a press corps so bent on destroying Trump that it will publish any incriminating information it encounters without proper journalistic rigor.

That she didn't publish is evidence that caricatures of what Sean Hannity calls the “alt-radical-left-propaganda-destroy-Trump media” (catchy, right?) are a bit inflated.

But there is no glory in avoiding a mistake. There is only shame in making one, and it appears that bad-faith sources are working hard to increase the media's error rate.