When news broke that Michael Cohen pleaded guilty to lying to Congress about his 2016 meetings concerning the failed Trump Tower Moscow project, the chattering class instantly began talking about the failed Trump Tower Moscow project.

Of course that was news. But it turns out the Cohen plea agreement also made news in what it did not cover. Specifically, it spoke volumes — without saying a word — about a key allegation of the Trump dossier, the charge that Cohen traveled to Prague to arrange secret payments to Russian hackers attacking the Clinton campaign. The accusation is the heart of the collusion allegation, and Trump-Russia special counsel Robert Mueller's deal with Cohen strongly suggests that prosecutors have not found evidence to support it.

[READ: Michael Cohen's plea agreement]

Cohen's guilty plea is an admission that he lied in a written statement to Congress. Actually, it was two statements, one in August 2017, and the other the next month. In the August statement, Cohen said the Trump Tower Moscow project was "under consideration ... from September 2015 until the end of January 2016," but by late January Cohen had "determined that the proposal was not feasible for a variety of business reasons."

In the September statement, Cohen said the Trump Tower Moscow project "was terminated in January of 2016; which occurred before the Iowa caucus and months before the very first primary."

In the plea, Cohen admitted that those statements were false, and that in fact he had continued discussions about Trump Tower Moscow into the summer of 2016.

"Cohen made the false statements," the criminal information said, "to (1) minimize links between the Moscow Project and [Trump] and (2) give the false impression that the Moscow Project ended before 'the Iowa caucus and ... the very first primary,' in hopes of limiting the ongoing Russia investigations."

That is the Trump Tower Moscow part of the story. But Cohen's statements to Congress were about more than just Trump Tower Moscow. In particular, one of the Cohen statements contained a vehement denial of the Prague allegation.

A quick reminder of what the Prague tale was: In the dossier, former British spy Christopher Steele cited a "Kremlin insider" who reported that Cohen traveled to Prague in August 2016 for talks with Russians with close ties to the Kremlin. The talks, according to the dossier, focused on "questions on how deniable cash payments were to be made to hackers who had worked in Europe under Kremlin direction against the CLINTON campaign and various contingencies for covering up these operations and Moscow's secret liaison with the TRUMP team more generally."

Cohen publicly denied the allegation, saying the meeting never happened and he had never been to Prague. In his September 2017 statement to Congress, Cohen was adamant: "I have never in my life been to Prague or to anywhere in the Czech Republic," he wrote. "Let me tell you where I was on the day the dossier said I was in Prague. I was in Los Angeles with my son who dreams of playing division 1 baseball next year at a prestigious university like USC. We were visiting the campus, meeting with various coaches, and discussing his future. Media sources have been able to confirm these facts and I can provide you with proof."

This is why Cohen's Trump Tower Moscow plea agreement with Mueller is important for the dossier: The plea shows that Mueller closely scrutinized everything Cohen told Congress. And it has long been clear that Mueller and his team are not shy about charging Trump-Russia figures with making false statements. It's also clear that Mueller found evidence that specific assertions in Cohen's statements to Congress were false — the ones concerning Trump Tower Moscow — and that he charged Cohen with lying. So if Mueller had evidence that Cohen's definitive denial of the Prague story, in the same document, was false, it seems reasonable to conclude that Mueller would have charged Cohen for it. Yet in the charges against Cohen, Mueller said absolutely nothing about Prague.

Last April, McClatchy published a blockbuster story with the headline "Sources: Mueller has evidence Cohen was in Prague in 2016, confirming part of dossier." The story was the subject of a lot of talk among Resistance types. But one notable thing about the McClatchy scoop was that other news organizations never duplicated it, as is common when one outlet breaks a big story. Now Mueller, with vastly more resources and investigative power than any news organization, hasn't either.

For more than a year, a number of Trump-Russia investigators on Capitol Hill have maintained that none of the dossier's substantive allegations are true. The new plea deal between Cohen and Mueller is more evidence to support that.