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.

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.

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. READ MORE: