"If true" are two of the most dangerous words in journalism. They were spoken hundreds of times in the coverage of BuzzFeed's potentially explosive report.
On Thursday night BuzzFeed rocked the worlds of politics, media and law with its story, attributed to two sources, that President Trump told Michael Cohen to lie to Congress.
But now there's been a shift from "if true" to "what's untrue." The office of special counsel Robert Mueller said Friday evening the story contained information that is "not accurate."
Now there is an extraordinary dispute between BuzzFeed and Mueller.
The special counsel took the extremely rare step of issuing a statement and purposefully casting doubt on BuzzFeed's story. But BuzzFeed says the special counsel should explain what, exactly, is inaccurate.
"We really urge the special counsel to make it clear what he's disputing," editor in chief Ben Smith said on CNN's "AC360" Friday night.
That's unlikely to happen. In the meantime, BuzzFeed is exuding confidence about its original story, even as journalists at other newsrooms express doubts.
On Saturday a spokesman for the news division said, "As we've re-confirmed our reporting, we've seen no indication that any specific aspect of our story is inaccurate. We remain confident in what we've reported, and will share more as we are able."
The story is still displayed prominently on the BuzzFeed News homepage: "President Trump Directed His Attorney Michael Cohen To Lie To Congress About The Moscow Tower Project."
The subheadline says "Trump received 10 personal updates from Michael Cohen and encouraged a planned meeting with Vladimir Putin."
BuzzFeed added a line on Friday evening noting that the special counsel's office had "disputed aspects of" the story.
No other major news outlet has been able to match BuzzFeed's reporting, which was attributed to "two federal law enforcement officials."
This has spurred skepticism about the validity of the report. CNN crime and justice reporter Shimon Prokupecz tweeted Friday, "If Mueller has evidence that Cohen lied at the direction of the Trump, you'd think it would have come out."
Writing in The Hill, Jonathan Turley criticized the "boom and bust pattern" of stories that sparked "imminent prosecution and impeachment" talk, "only to be followed by mitigating or conflicting evidence on each allegation."
But Smith, speaking on "AC360," pointed out that reporters Jason Leopold and Anthony Cormier have previously been "way out in front" on stories about Trump Tower Moscow that were later confirmed.
Smith said he knows the identities of the two sources in Thursday's story. "We're really confident in these specific sources," he said.
So now BuzzFeed is going back to the sources to try to glean more information. The news outlet's credibility is on the line in a big way, and some journalists are predicting that this episode will not end well.
BuzzFeed has its defenders too, however. Many observers see this as an unsolved mystery.
"My best guess is, in the long run, the BuzzFeed piece will prove to be right ballpark, wrong inning," veteran investigative reporter David Cay Johnston told CNN Business.
President Trump and allies are using the controversy to tar not just BuzzFeed, but the national news media as a whole.
Toronto Star fact-checker Daniel Dale pointed out that Trump told reporters on Saturday morning that "mainstream media has truly lost its credibility," but "then, two sentences later, lied for the 13th time that the New York Times issued a post-election apology for its coverage. The Times never apologized."
On social media, some Trump supporters celebrated the BuzzFeed controversy by calling it "BuzzFraud." Fox News went with "Buzzkill" in a headline. The Drudge Report went with "Buzzbleed!"
This, in turn, sparked some strong defenses.
"Those trying to tar all media today aren't interested in improving journalism but protecting themselves," NBC's Chuck Todd tweeted. "There's a lot more accountability in media these days than in our politics. We know we live in a glass house, we hope the folks we cover are as self aware."
CNN legal and national security analyst Susan Hennessey pointed out that Cohen will have a chance to resolve the mystery sooner rather than later.
On Twitter, Hennessey predicted that "the very first question Michael Cohen will be asked in his congressional testimony is 'Did the President ever instruct or encourage you to lie to Congress or federal investigators?'"
The Cohen hearing is scheduled to take place on February 7.