Special counsel Robert Mueller’s team of prosecutors have spent several days building what many legal experts consider a slam-dunk case against President Donald Trump’s former campaign chairman, Paul Manafort.

But it has been surprisingly hard going at times, and as they prepare to rest their case by the week's end, they bear battle wounds that Manafort’s lawyers are sure to exploit as they mount their defense.

Even as Mueller’s team methodically piled up evidence of Manafort’s alleged tax and bank fraud, jurors have seen the special counsel’s case hit some potholes.

Most notably, Manafort’s attorneys have painted the prosecution’s star witness, Rick Gates, as a serial liar, embezzler and philanderer who — as a defense lawyer asserted in court on Wednesday — engaged in four extramarital affairs.

Several other setbacks have come courtesy of the cantankerous presiding federal judge, T.S. Ellis III.

The 78-year-old Ronald Reagan appointee has repeatedly tweaked Mueller’s team, on everything from the logic of their assertions to a prosecutor’s informality in answering a question with a “yeah” instead of “yes.” He has hurried along their case and blocked them from introducing some evidence of Manafort’s lavish lifestyle.

Taken on their own, the individual rebukes are relatively minor. But some legal experts say that, cumulatively, they could plant doubt in the mind of jurors about the strength of the prosecution’s case. Renato Mariotti, a prominent former federal prosecutor, tweeted Wednesday that Ellis has made “improper statements that have hurt the prosecution.”

“[T]he judge’s condescending attitude [could give] the jury the impression that the prosecution’s case is dubious,” added Philip Lacovara, a former U.S. deputy solicitor general. “This is an especially severe risk when the core of the case is the testimony of a co-conspirator who is admittedly a thief, liar, and embezzler. When the standard of proof is ‘beyond a reasonable doubt,’ there is no margin for error.”

Mueller's team even filed a formal written protest on Thursday about the judge's behavior, complaining that prosecutors were being unfairly called out in front of the jury.

The jury and not Ellis will decide Manafort’s fate. But the rulings and commentary of a seasoned judge are sure to have influence over jurors.

In what must have been a particularly unwelcome exchange for Mueller’s team, Ellis on Tuesday tweaked Gates, who admitted to embezzling expense money while working for Manafort. The judge also seemed to give credence to Manafort’s argument that he did not keep close enough track of his money to commit knowing fraud and tax evasion.

“Mr. Manafort was very good about knowing where the money is and knowing where to spend it,” Gates said.

“Well, he missed the amounts of money you stole from him, though, didn't he?” the judge said.

Gates conceded that was true.

“So, he didn't do it that closely,” the judge quipped, to some laughter in the courtroom.

On Wednesday, Ellis was at it again, dressing down prosecutors after learning that an IRS agent they called to the stand as an expert witness had been in the courtroom for the entire trial. Ellis argued that witnesses should be present only for their own testimony. Mueller’s prosecutors protested that the judge had granted them an exception, but the judge — a former fighter pilot who has spent more than 30 years on the federal bench — was having none of it.

“I don’t care what the transcript says, maybe I made a mistake,” Ellis said. “When I exclude witnesses I mean everybody, unless I make a special exception.”

Also Wednesday, Ellis asked whether snaking flow charts Mueller’s team presented as evidence showing complex financial transfers funding Manafort’s real estate purchases were meant to signify illegal behavior beyond a failure by Manafort to report taxable income.

“One can get lost in all these movements of money,” Ellis told Greg Andres, one of Mueller’s most senior litigators and a former top lawyer in the Justice Department’s criminal division. “Sometimes it seems that’s what the government is aiming at. But you’ve confirmed that it is not.”

And when Ellis asked Andres — with whom he colorfully sparred on Monday — one procedural question in front of jurors, the admittedly old-fashioned judge bridled when the prosecutor answered with a casual-sounding “yeah.” Read more at Politico