How Michael Flynn’s Defense Team Found Powerful Allies

When Mr. Flynn stood in Judge Sullivan’s courtroom on Dec. 18, 2018, his legal odyssey appeared to be over. He had struck a favorable deal with Mr. Mueller’s prosecutors to cooperate after admitting to lying to F.B.I. agents about conversations with the Russian ambassador in late 2016. In exchange, prosecutors were recommending he receive no prison time and would not be prosecuted for separate offenses related to his lobbying for Turkish government without registering as an agent of a foreign power.

But he did not go quietly. His defense team, in a memo laying out what sentence he should receive, also floated the notion that Mr. Flynn had been set up. F.B.I. agents had used several different tactics to essentially trick Mr. Flynn, a retired Army three-star general, into making false statements, the memo suggested.

The Flynn defense team was trying to have it both ways, and Judge Sullivan was furious. He grilled Mr. Flynn about whether he was truly taking responsibility for his crimes and even suggested — before retracting the notion — that Mr. Flynn had been a traitor to his country. When it appeared that Judge Sullivan might send Mr. Flynn to prison, going beyond the original recommendation of prosecutors, Mr. Flynn and his lawyer, Robert K. Kelner, decided to postpone the sentencing so he could continue to cooperate with prosecutors.

Judge Sullivan, appointed to the federal bench by President George Bush, has a reputation as a hard-nosed jurist with a disdain for prosecutorial misconduct. He is known for taking guilty pleas seriously, and he reminded Mr. Kelner that he had never accepted one from someone who maintained he was not guilty and that he “didn’t intend to start today.”

In his legal pivot, Mr. Flynn had channeled the campaign led by Mr. Trump and his allies that had portrayed the Russia investigation as a “witch hunt” and a plot to sabotage his presidency. Since Mr. Flynn had first pleaded guilty in 2017, Republicans in Congress had taken up a campaign to undermine the case against him and portray him as a victim of overzealous prosecutors.