Former National Security Adviser Michael Flynn is expected to plead guilty to lying to the FBI — and that's very bad for Trump and his administration.

With the earth-shattering news on Friday morning that Donald Trump’s former national security adviser, Michael Flynn, is expected to plead guilty to lying to federal investigators in special counsel Robert Mueller’s investigation of Russia, the question on everyone’s mind is now what happens next.

The answer is unclear, but one thing that is certain is this is huge trouble for the Trump administration.

Reporter Errol Louis laid out the enormous gravity of the situation on CNN in conversation with John Berman:

BERMAN: I think that perspective is necessary here. The president’s national security adviser — at least for a few days — pleading guilty to lying to the FBI. The president’s one-time campaign chairman has been charged with a crime. These are major figures.

LOUIS: These are major—

BERMAN: Major associates to then candidate, President Trump.

LOUIS: That’s, that’s exactly right. This isn’t a nothingburger. This isn’t fake news. This is as real as it gets.

And it is about to get even more real.

Flynn was a massively important member of the Trump campaign and then the administration. The allegations against him — which range from illegally concealing foreign lobbying to conspiracy to kidnap a Turkish dissident — are extremely serious. If Mueller is willing to let him plea down his crimes, the only logical explanation is that he has incriminating evidence on someone even higher up in the administration.

Who that could be is anyone’s guess. Flynn might be able to prove that Attorney General Jeff Sessions committed perjury when denying knowledge of the Trump campaign’s Russian contacts to the Senate. He might be able to prove Vice President Mike Pence was a knowing co-conspirator in efforts to work with Russia.

Or he might possibly even have evidence against Trump himself — which would lay the formal foundation for impeachment.

Mueller’s investigation could go in a number of directions, but for Trump’s inner circle, Flynn’s cooperation spells disaster.