Elie Honig, a former federal and state prosecutor, is a CNN legal analyst and a Rutgers University scholar. The views expressed in this commentary are his own. View more opinion articles on CNN.

(CNN) President Donald Trump lashed out on Thursday at his former personal attorney Michael Cohen after Cohen's guilty plea to a new criminal charge in the Southern District of New York. While Trump might want to practice his poker face a bit when facing adversity, it is easy to see why he is so visibly flustered.

Cohen's guilty plea cements the Trump Organization's financial ties to the Russian state, deep into crucial phases of the 2016 election cycle. And, even beyond what we learned Thursday, Cohen promises to deliver more damning information about Trump and his campaign to special counsel Robert Mueller in the weeks ahead.

We now know that Cohen is cooperating with Mueller. While the document to which Cohen pled guilty in August (called an "Information," which is essentially an indictment that both parties agree to) was signed by attorneys from the Southern District of New York U.S. Attorney's Office, today's document is signed by Robert S. Mueller III himself

That suggests two important things. First, while the subject matter of Cohen's August plea -- bank fraud, tax fraud, and campaign finance fraud -- arguably fell in the margins of Mueller's mandate to investigate Russian interference in the 2016 election, this plea is right down the middle of the Trump-Russia relationship.

Second, Mueller apparently has now confirmed to his satisfaction that Cohen is being truthful and that his information can be corroborated by external evidence. On Wednesday, Trump stated of Mueller's investigative practices that "this flipping stuff is terrible" and that prosecutors use tactics from the "Joseph McCarthy era" and routinely pressure witnesses to lie.

This is flatly untrue. I worked as a prosecutor for 14 years, and I know firsthand that prosecutors are, if anything, obsessed with ensuring that cooperators tell the truth, whether it helps or hurts a potential target. This is why prosecutors focus so intently on corroboration, independent evidence that confirms the cooperator's testimony.

For an example of this vetting process in action, look no further than Paul Manafort, who flamed out as a cooperator earlier this week. Prosecutors on Monday informed a federal judge that Manafort had lied to them. For Mueller, and for any good prosecutor, that is a deal-breaker. Mueller consequently rejected Manafort as a witness -- even though Manafort likely could have offered a rare look into the Trump campaign's inner sanctum -- because Manafort lied during the cooperation process.

Cohen now has gotten through that vetting process, apparently to Mueller's satisfaction.

JUST WATCHED Trump reacts: Michael Cohen is a 'weak person' Replay More Videos ... MUST WATCH Trump reacts: Michael Cohen is a 'weak person' 01:37

Trump, like a typical boss, recognizes the threat posed by cooperation, and rails angrily against it.

Before he boarded Air Force One on Thursday, Trump took a few swipes at Cohen, calling Cohen "very weak" and accusing Cohen of "lying."

This is Cooperator Bashing 101 -- standard, textbook stuff from a frightened target of a criminal probe. As Trump seems to understand, cooperating witnesses often pose the gravest threat to the leaders of closed, corrupt, hierarchical organizations. When I was working as a prosecutor, I typically built organized crime cases by working with cooperating lower-level players against mid-level players and then with mid-level players against bosses.

Trump is also demonstrably wrong and Cohen is provably correct about the timing of the Trump Organization's efforts to build a lucrative new property in Moscow (what the Information calls the "Moscow Project"). Cohen pled guilty Thursday to lying to Congress when he testified that the proposed Moscow Project ended in January 2016.

Evidence cited in the Information shows the discussion of getting the deal approved carried on into June 2016 -- after Trump had become the presumptive Republican nominee. Trump appears to claim that Cohen is lying when he says that the deal carried into June 2016. Yet the Information quotes documents -- presumably texts or e-mails -- from May and June 2016 in which Trump Organization members give instructions to Cohen about the then-still-ongoing "Moscow Project."

The proof is right in those documents, in black and white: Cohen may have misled Congress before about the timing of the Moscow project, but he is not lying now.

JUST WATCHED Schiff: If Cohen misled, Trump misled country Replay More Videos ... MUST WATCH Schiff: If Cohen misled, Trump misled country 01:18

Trump also argued Thursday that the Moscow deal never happened , so what does it matter? It matters because, while he was trying to open the new properties in Moscow, Trump's proposal " would require approvals within the Russian government ." Whether the Moscow project succeeded or not, Trump needed to curry favor with the Russian government to get the necessary approvals to move it forward.

That incentive to curry favor with the Russian state raises several key questions. Did the late-breaking change to the Republican platform in 2016 , taking a softened position on Russia, have anything to do with the Trump Organization's effort to obtain approvals from the Russian state for the Moscow Project? Did Trump's hiring of Manafort as campaign chair, for no salary, have anything to do with Manafort's deep ties to pro-Vladimir Putin Russian oligarchs ? Is there any connection between the Trump Organization's business dealings with Russia and the Russian state's effort to hack the e-mails of Hillary Clinton and the Democratic National Committee, among others?

All of this may just be a warmup for what lies ahead. Now that Cohen is cooperating, Mueller likely knows everything that Cohen knows. Mueller therefore can use Cohen's information to probe Trump's involvement in any number of things, including potential campaign finance violations arising from hush money payments made to Stephanie Clifford and Karen McDougal -- which Cohen himself pled guilty to in August, directly implicating Trump.

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Federal cooperation is all-or-nothing. The cooperator does not get to choose what information he gives to prosecutors or who he cooperates against. Everything is fair game. So if Cohen knows it, then Mueller should know it now, too. That should cause Trump some restless nights ahead.

This article has been updated to replace a reference to an "Indictment" with the more legally specific term, "Information."