ANALYSIS: Michael Flynn's guilty plea opens more doors than it closes It should scare White House officials as they hunker down for an investigation.

 -- Michael Flynn’s guilty plea opens more doors than it closes.

That should scare White House officials as they hunker down for an investigation that’s inching ever closer to the Oval Office – and still looks like it’s nowhere near completion.

The sparse legal documents filed today by the special counsel indicate that Flynn is pleading guilty to a single count of lying to federal investigators.

With that, President Donald Trump’s first national security adviser becomes a convicted felon for misleading the FBI about contacts he had with the ambassador from Russia – a country that was accused by the nation’s intelligence agencies of meddling in the presidential election before those contacts.

Yet, that’s the least of White House worries at the moment.

Left unsaid in today’s legal filings is the extent to which Flynn is cooperating with special counsel Robert Mueller’s team – and what insights he might be able to provide that point toward collusion with the Russians and interactions with Trump family members.

The retired Army general has promised his “full coordination” with the Mueller investigation, ABC News is reporting. Flynn is prepared to testify that Trump directed him to make contact with the Russians, in the context of plans to defeat ISIS.

This is a game-changing development with far-reaching implications.

The indictments of former campaign manager Paul Manafort and his longtime associate, Rick Gates, were for lobbying activities that long predated their connections to Trump. The guilty plea of George Papadopoulos, the former Trump campaign foreign-policy adviser, was dismissed by Trump allies as a low-level campaign volunteer essentially freelancing to make contacts with the Russians.

White House attorney Ty Cobb sought to minimize the import of today’s news. He said in a statement that Flynn held a job under the president for only 25 days – after which he was fired for the same lies the FBI caught him on.

“Nothing about the guilty plea or the charge implicates anyone other than Mr. Flynn,” Cobb said in a statement. “The conclusion of this phase of the Special Counsel's work demonstrates again that the Special Counsel is moving with all deliberate speed and clears the way for a prompt and reasonable conclusion.”

But it’s not nearly that simple.

Flynn was a top-level campaign adviser who consulted and traveled frequently with Trump himself last year – even leading the Republican National Convention in a “lock her up” chant that will live in infamy.

Flynn then became Trump’s national security adviser despite concerns conveyed repeatedly to Trump that he was either untrustworthy or potentially compromised by the Russians. He was fired only after it became clear that he misled Vice President Mike Pence about the very contacts with the Russian ambassador he also is now admitting lying to the FBI about.

That action in itself could have been illegal, owing to a centuries-old law prohibiting private citizens from negotiating on behalf of the United States with foreign entities. Flynn isn’t being charged in connection with the Logan Act.

He also isn’t being charged with anything connected to the failure to properly register his lobbying work on behalf of foreign governments.

His son, Michael Flynn Jr., also is not currently facing any charges, despite widespread reporting of his travels abroad with his father, and his connections to his lobbying business.

What’s being left out by prosecutors could indicate what Flynn is able to bring to Mueller’s table. There’s also the intriguing matter of Trump’s intense interest in the Flynn case.

Former FBI director James Comey has testified before Congress that the president asked him to drop any investigation of Flynn: “I hope you can see your way clear to letting this go, to letting Flynn go,” Trump told Comey, according to the since-fired FBI director.

Back in March, when Flynn was in negotiations with Congress to provide testimony, his lawyer hinted that he had much to say.

"General Flynn certainly has a story to tell, and he very much wants to tell it, should the circumstances permit,” the lawyer, Robert Kelner, said at the time.

Circumstances now permit Flynn to tell his story – to the special counsel whose inquiry started with Russia and appears to have expanded from there.

This should scare Trump allies about the weeks and months ahead.