The sentencing of Michael Flynn was postponed Tuesday after the judge told the former national security advisor "arguably you sold your country out" — and warned the fallen Army lieutenant general that he might be sent to jail if he did not agree to delay the hearing. Flynn was due to be sentenced Tuesday for lying to FBI agents about his conversations with Russia's then-ambassador to the United States, Sergey Kislyak, in the weeks before President Donald Trump took office. Federal guidelines recommended a sentence of zero to six months in jail. Flynn's lawyers and prosecutors from special counsel Robert Mueller's office were prepared to argue in U.S. District Court that Flynn receive either no jail time at all — given his guilty plea and extensive cooperation with Mueller — or get the low end of the guideline range. But that plan was immediately thrown into disarray at an explosive hearing at which Judge Emmet Sullivan pressed the defense hard on its recent suggestions that the case against Flynn was unfair. The judge said that looked liked "backpedaling" from the guilty plea. Sullivan, who also asked if Mueller had ever contemplated charging Flynn with "treason," later suggested that Flynn might get a less severe sentence once he was actually done cooperating with investigators. "If you want to postpone this, and come back at some later point ... that's fine with me," the judge said. "I have to caution you that the sentence imposed today may not be the same sentence you would get after cooperation ends," Sullivan said. "The court likes to be in a position to say there is nothing else this defendant can to do help the United States of America." No new sentencing date was set.

Former White House National Security Advisor Michael Flynn leaves the Prettyman Federal Courthouse following a sentencing hearing in U.S. District Court December 18, 2018 in Washington, DC. Chip Somodevilla | Getty Images

Sullivan, noting that he still has "many, many, many more questions," told defense lawyers and prosecutors to submit a status report by March 13. "Happy holidays," the judge said, as he recessed the sentencing hearing, before Flynn walked out of Washington courthouse into a waiting car. The delay will allow Flynn to possibly help federal prosecutors in Virginia with a new case. In that case, two former Flynn associates are charged of conspiring in a plot with Flynn to push for the extradition for an exiled Turkish cleric to Turkey, without informing the United States government they were acting as agents for a foreign country. Flynn, who was not referred to by name in that indictment, was involved in the efforts to smear the exiled cleric. Turkey's president claims the cleric orchestrated a 2016 coup attempt. "All along, you were an unregistered agent of a foreign country while serving as the national security advisor to the president of the United States," Sullivan told Flynn, referring to the other case, for which Flynn was not charged. "That undermines everything this flag over here stands for," the judge said. "Arguably you sold your country out." Sullivan told Flynn that if he did not accept an offer to postpone his ongoing sentencing hearing, "I cannot assure you that if you proceed today, you will not receive a sentence of incarceration." "This is a very serious offense," said Sullivan. "A high ranking senior official of the government making false statements to the Federal Bureau of Investigation while in the White House," Sullivan said. "Very serious crime," Sullivan told the 60-year-old retired Army lieutenant general. "Can't minimize that." "I'm not hiding my disgust, my disdain," the judge said. "Hypothetically could he have been charged with treason?" Sullivan asked prosecutor Brandon Van Grack. Van Grack answered, "Because It's such a serious question, I am hesitant from answering." Sullivan later said: "I wasn't suggesting he was committing treason. I was just curious if he could have been charged. Lots of conspiracy theories out there. Not taking any uncalled offenses into consideration. Was trying to consider benefit. I'm not suggesting treason. " Van Grack said, "The government has no reason to believe the defendant committed treason." Sullivan offered Flynn the chance to postpone the sentencing in light of a prosecutor's statements that he could continue cooperating with them even after Tuesday. Sullivan called a recess after Flynn accepted the judge's offer of time to speak with his lawyers. When court resumed, Flynn's lawyers told him they wanted to postpone the sentencing.