The guilty plea of former national security adviser Michael Flynn, who on Friday admitted to making false statements to the FBI about his contacts with Russia, is very significant.
First, in Flynn, not only has a member of US President Donald Trump's campaign team been charged but also a former high-ranking official in the administration.
Second, despite the White House downplaying the charges by saying that Flynn was only in the administration for a short time, he was one of the most important foreign policy advisers, if not the most important, to the future president during the election campaign. Trump's high esteem for Flynn led him to be appointed national security adviser, a position that doesn't require congressional approval, against the advice of many experts.
Third, Flynn's guilty plea is a clear indication that he has provided important information to Special Counsel Robert Mueller, who will be able to use that information to prepare investigations and charges against more significant figures.
"That's the real story here. That he agreed to cooperate in exchange for favorable treatment from Mueller," said Jimmy Gurulé, a former assistant attorney general at the Justice Department and a law professor at the University of Notre Dame.
"You don't enter into a plea agreement unless the prosecutor has determined and independently corroborated that the potential witness has substantial, credible and reliable evidence that would implicate higher ups in the criminal enterprise in unlawful activity."
According to Brandon Garrett, a law professor at the University of Virginia, Flynn has likely already given up valuable information to investigators.
"A plea deal would only have been offered once there was real cooperation," he said.
Lisa Kern Griffin, a criminal law scholar at Duke University, noted that Flynn appears to have gotten off lightly, although further charges are still possible.
Making false statements to the FBI is a felony that carries a prison sentence of up to five years. But under the deal with Mueller, Flynn can expect only six to 12 months in prison, or possibly a suspended sentence, Griffin said.
That's almost nothing, she added, compared to what the public record of Flynn's activities suggests, which could have led to multiple charges.
In addition, no charges have been brought against Flynn's son, who according to media reports was in Mueller's sights over an alleged plot to kidnap US-based preacher Fethullah Gulen, who is wanted by the Turkish government over last year's failed coup attempt.
Since Mueller's strategy is to work his way up to "big fish" through indictments and deals with "small fish," the net around potential targets will now become smaller. After all, as former national security adviser, Flynn was already fairly high up in the White House hierarchy.
For legal experts, there are only a few people in Mueller's sights, and high on this short list stands Jared Kushner, Trump's son-in-law and senior White House adviser.
"There were a number of ways during the campaign that Michael Flynn and Jared Kushner were working together and at a minimum I suspect that Michael Flynn has damaging information to offer about Jared Kushner," Griffin said.
According to US media reports, Kushner is the "very senior member" of the Trump transition team who directed Flynn to make contact with former Russian ambassador Sergey Kislyak in 2016.
Trump's son could also be targeted by Mueller, noted Gurulé. "To me the other potential target is Donald Trump Jr. There is reason to believe that he is being targeted based on this June  meeting in the Trump Tower [with a Russian lawyer and others — Editor's note], where he appears to be excited over the possibility of Russian dirt on Hillary Clinton," he said.
Beginning of the end for Trump?
Although many Trump critics — on social media and elsewhere — may be tempted to see Flynn's plea deal as the beginning of the end for the president, it's still premature to conclude whether or not Flynn may implicate others in Trump's inner circle.
For legal experts, this is only a step, even if a significant step, in the long process of Mueller's investigation. Certainly, it's true that the charges have been getting ever closer to the president. But Trump has, so far, never directly been under investigation. And it remains constitutionally questionable whether a sitting president can even be charged.
Griffin thinks it's unrealistic to assume Trump will soon be leaving office — at least at this point in time. She believes the question over Trump's future will likely not to be answered legally, but rather politically in next year's midterm elections.