2 December 2017 Donald Trump is isolated and alone after the arrest of Michael Flynn Trump's nemesis Comey gleefully tweeted: “But justice roll down like waters and righteousness like an ever-flowing stream.” Getty Sign UpGet the New Statesman's Morning Call email. Sign-up On 9 May 2017, FBI director James Comey was ignominiously fired by Donald Trump, beginning a chain of events that led to the appointment just a few days later of a special investigator to look into Russian interference in the 2016 presidential election. On 1 December, that investigator, Robert Mueller, arrested Michael Flynn, a former general and top adviser to Trump who was picked to serve as the new president's National Security Advisor. When he heard the news, Comey gleefully tweeted a Biblical verse: “But justice roll down like waters and righteousness like an ever-flowing stream.” Flynn notably said at the Republican National Convention last year that “if I had done one tenth what she [Hillary Clinton] had done, I'd be in jail” before leading the crowd in chants of “Lock Her Up”. On Friday morning, he surrendered to authorities and filed a plea of guilty later that day to one charge of making a false statement to the FBI. Outside the courthouse, activists mockingly echoed his 2016 RNC appearance, chanting “Lock Him Up”. Even more than that of campaign chairman Paul Manafort and foreign policy adviser George Papadopolous a few weeks ago, this latest arrest spells bad news for Trump. Flynn has committed to full cooperation with Mueller's investigation, which Trump has repeatedly and pathetically slammed as a “witch hunt”. According to court documents, Flynn has told Mueller that he was directed by a “very senior” transition team figure to make contact with Russia in order to discuss the sanctions that president Obama had imposed. That figure, according to reports, is likely Trump's son-in-law, Jared Kushner, who had been given a wide-ranging foreign policy brief during the transition. He could be the next target of Mueller's attention. It is also possible that a direct link to Trump himself could be made, if Flynn plans to testify that the instruction to contact the Russians came directly from the then-president-elect. That Flynn lied about contacting Russian ambassador Sergey Kislyak is already known – the revelation that he had lied to vice-president Mike Pence about that conversation is what led to his being fired after just a few days in the job as Trump's National Security Adviser. Sally Yates, then acting attorney general, raised the alarm over Flynn's potential as a blackmail target with the Trump White House the day before Comey was fired, but it took Trump's team two more weeks to finally fire Flynn. Some Democrats on Friday were speculating that Trump could be prosecuted under the Logan Act, a rarely-used statute which makes it illegal for any private citizen to undermine a president's foreign policy, Bloomberg reported. The argument would then be that Trump, by contacting the Russians privately, undermined then-president Obama's policy of sanctions by secretly assuring the target that they would be lifted or eased once the new administration entered the White House. Mueller has plenty of leverage over Flynn; as the New York Times' Charlie Savage has pointed out, there were plenty of other crimes he could have been charged with if he had refused to cooperate, including those related to illegal or undisclosed lobbying activity on behalf of both Russian and Turkish institutions during the transition. On top of that, notably left out of the arrests so far has been Flynn's son, Michael Jr, who served as his father's chief of staff, leading some to speculate that Flynn may have cooperated more readily in order to protect his son. It is still not known what the full extent of Flynn's cooperation means, and exactly what he has told Mueller, but his arrest means that the investigation has cracked Trump's inner circle. Trump is increasingly isolated in a shrinking circle of loyalists and family members. He reportedly told coastguard members last Thursday, during a Thanksgiving address, that “you never know about an ally. An ally can turn,” which many have taken to be a swipe at Flynn for cooperating with Mueller. Flynn, whom Trump hired over the advice of his predecessor, cannot be dismissed as a minor player in the campaign, and Trump will be fretting about what his cooperation might mean. Mueller, a former FBI director himself – he was Comey's predecessor and mentor – has been relentless in his pursuit of Trump, and his team's rigid discipline is even more visible when compared to the increasing chaos within the president's inner circle. Trump has been tied up trying to pass his landmark tax plan through Congress (the bill passed through the Senate the same day Flynn was arrested), and is feuding both with secretary of state Rex Tillerson and British Prime Minister Theresa May. It is important to note that we still haven't seen a smoking gun of collusion. Flynn's guilty plea was only to the crime of lying to investigators over the Kislyak meeting. Trump's lawyer, Ty Cobb, has been making hay on this point, noting that Flynn was the only one implicated on Friday. But the drumbeat is certainly getting louder. More important than what was in the Flynn indictment is what was not; crimes that were not included can probably be assumed to be part of the negotiation to persuade Flynn to switch sides and work with the investigation; and if someone as senior as the National Security Adviser has been offered a deal to flip, then it can be safely speculated that Mueller has a bigger target in mind. Flipping Flynn may give Mueller access to corroborating evidence of some of the more activities that we have seen hints of in Papadopolous's indictment and in the emails released by Donald Trump Jr. If it can be proved that Trump himself knew about Russia's offer of “dirt” on Hillary Clinton, let alone that he actively encouraged it (as we know he obliquely did in a campaign speech), then we might be approaching impeachment territory. But we aren't there quite yet. Nonetheless, the president will surely be feeling under pressure now. The closer Mueller gets, the fewer options are left to Trump, who may soon find himself with just two choices left: plead guilty, or plead incompetence. › Richard Nixon: the Life sheds light on all the president’s demons Nicky Woolf was the launch editor for New Statesman America and has formerly written for the Guardian and the New Statesman. He tweets @NickyWoolf. Subscribe For more great writing from our award-winning journalists subscribe for just £1 per month!