To judge in Manafort trial, courtroom is 'Rome' and he is 'Caesar' The 30-year veteran of the bench has a unique style of presiding over a trial.

When you walk into Courtroom 900 in the federal court house in Alexandria, Virginia, you step into another domain, a territory ruled not by a mayor or a governor or even a president, but by a self-proclaimed emperor.

"I'm a Caesar in my own Rome," Judge T.S. "Tim" Ellis recently told a defendant. "And it's a small Rome."

Ellis, the 30-year veteran of the bench who is presiding over the government's financial crimes case against former Trump campaign chairman Paul Manafort, is well-known in legal circles for his colorful commentary. But his unique style –- and his seemingly harsh treatment of government prosecutors –- has at times stunned observers and stolen the spotlight in the first significant trial to spring from Special Counsel Robert Mueller's ongoing investigation of Russian interference in the 2016 elections.

His pointed remarks have made headlines -- he warned attorneys on both sides to "rein in your facial expressions" last week -- but legal experts say his behavior could have a more significant impact on the jurors assigned to the case.

"Jurors will likely view the judge as the arbiter of fairness and appropriate conduct," Robert Mintz, a former federal prosecutor now in private practice, told ABC News. "Any inference by the judge that the prosecution is not playing by the rules can play into the defense strategy that this case is a classic government overreach motivated at least in part by political considerations."

Mintz told ABC News that it is not entirely uncommon for judges in criminal trials to clash more with the prosecution than the defense. The vast majority of a trial, Mintz said, is typically spent on the prosecution’s case, since the prosecution has the burden of proof.

It should also be noted that lawyers for Manafort, who has pleaded not guilty, have not yet presented their defense, so it remains to be seen how Ellis interacts with the other side.

But the judge's unpredictable pronouncements -- ranging from the self-deprecating to the biting –- have nevertheless hit a range of targets, including journalists.

"I'm not a watcher of TV or radio," he told jurors, as he counseled them to avoid news about the trial. Tuning out "might be more pleasant," he added with a grin.

Even before the trial began, Ellis reminded government prosecutors that "nobody has unfettered power" during a contentious preliminary hearing -– drawing words of encouragement from President Trump -— though he eventually ruled in the government's favor.

"These allegations clearly pre-date the appointment of the special counsel," he said just two minutes into the hearing. "None of it had any relation to the campaign."

As the trial got under way, his jabs at prosecutors intensified.

Ellis rejected the government's requests to show the jury scores of pictures depicting rows of suits purportedly purchased with money wired from overseas accounts, what the government said was evidence of Manafort's opulent lifestyle, telling prosecutors they need not "gild the lily."

"The government doesn't want to prosecute someone because they wear nice clothing, do they?" Ellis said.

Ellis admonished prosecutors for using the term "oligarch," which he said has "come to have a 'pejorative' meaning."

"We're not going to have this case tried as 'He associated with despicable people, therefore he's a despicable person,'" he said. "That's not the American way ... Call them 'financiers.'"

And Ellis has repeatedly demanded that prosecutors pick up the pace and once scolded a prosecutor for responding "Yeah," instead of "Yes, your honor."

Ellis and prosecutor Greg Andres appear to have a particularly acrimonious relationship. Bloomberg reported last week that, in a discussion out of earshot of the jury, Ellis told Andres he saw tears in his eyes.

"I understand how frustrated you are," Ellis said. "In fact, there's tears in your eyes right now." Andres denied it, but the judge was insistent: "Well, they're watery."

Later in the week, Andres' frustration appeared to boil over again, and he accused Ellis, through clinched teeth, of "constantly interrupting him." The judge fired back: "Let the record reflect that I rarely interrupt you," he said.

Andres said he stood by his position, to which Ellis responded: "All right. Then you will lose."

On Thursday, however, Ellis appeared to wonder whether one his barbs had crossed a line, telling the jurors to ignore his criticism of prosecutors over a decision to allow a witness to sit in court as other witnesses testified.

"I was critical of counsel allowing a witness to remain in the courtroom. You are to put that aside ... I was probably wrong," Ellis told the jurors. "This role doesn't make me any less human."

So far, Ellis has established the closest rapport with the jurors themselves. He has required everyone in his courtroom to stand when the jury enters each day. He has asked them about the quality of their lunch, teased them about their seat selections and commiserated with them about traffic, even pushing back the trial's start time to spare them the gridlock "headache."

And he has displayed flashes of humor meant to keep the heavy proceedings light. When he mangled the name of a fashion designer during discussion of Manafort's wardrobe, he turned apologetically to the jury: "If it doesn't say 'Men's Warehouse,' I don't know it."

But even the judge's attempts at humor can seem to cut against the prosecutors.

About halfway through a bookkeeper's testimony, with Andres leading the witness methodically through a thick binder of documents, Ellis interrupted.

"Move it along," he said, drawing chuckles from the jury. "We'll break for lunch as soon as Mr. Andres is finished."

When Manafort's longtime business partner Rick Gates, the prosecution's star witness, testified that the defendant "kept fairly frequent" track of his offshore accounts, Ellis was ready with a rejoinder.

"Well, he didn't keep track of the money you stole from him," Ellis quipped as the courtroom burst into laughter. "So [Manafort] didn't do it that closely."

John D. Cohen, a former senior homeland security official who is now an ABC News contributor, said the prosecutors have likely factored in the judge's behavior as they prepped for the Manafort trial.

"Most prosecutors who have had experience going before a judge such as Judge Ellis typically develop strategies to minimize any potential negative implications of the judge's behaviors," Cohen said. "That said, the court has to be very careful that the judge's behavior does not send a message to the jurors that the judge is opining of the veracity and accuracy of the evidence being presented."

Cohen said Ellis' behavior "could" have an effect on the jury, but added "as long as the judge doesn't impede the ability of the government to present their case in a fair and objective manner it shouldn't be too much of a problem."

Former federal prosecutor Mintz suggested that prosecutors could help their case by pushing back against the judge, but that strategy comes with a degree of risk.

"By pushing back against the judge, they can demonstrate their belief in the strength of their case," Mintz said. "But they do not want this trial to devolve into a battle of wills with the court and take the jury’s eyes off of the evidence."