At the defense table, Trump uses the courtroom as a stage

He shook his head angrily and sat with his back bent. He spoke to his lawyers and his words were sometimes clearly audible in the crowded courtroom. He wrote instructions for his defense team that he pushed their way. At one point he arrived late, and at another, while an attorney prosecuting him spoke to the jury, he strode out.

Former President Donald J. Trump's behavior while attending the defamation trial that ended Friday when a jury ordered him to pay $83.3 million to writer E. Jean Carroll — and his similar behavior in an ongoing civil case in New York – showed his disdain both for a justice system that wants to hold him accountable and for the protocols of courtrooms over which he has little control.

His use of the defense table as a podium also provided clues for the audience, and a reminder to his own legal team, of how he might handle himself if and when any of the four criminal cases he faces go to trial. In all of these cases, he will be required to be present throughout the proceedings, unlike the Carroll case or the New York Attorney General's case in which he is accused of corporate fraud, where he was allowed to attend both civil trials and not, as he wanted.

As he was finalizing the Republican presidential nomination, Trump appeared five days after the Carroll trial in the cavernous, wood-paneled Manhattan federal courtroom of Judge Lewis A. Kaplan, a veteran, no-nonsense lawyer who has handled notable terrorism cases. And for many days in recent months, he spent many days during the trial a few blocks away at 60 Center Street, where State Supreme Court Justice Arthur F. Engoron was overseeing the fraud trial against Mr. Trump and his company.

Trump, who has long confused legal issues with public relations concerns, quickly tried to use both courtrooms in the middle of his presidential campaign to get his own message across, a tactic that created a tense atmosphere.

In both trials, the pressure on him and his anger over accusations that struck at the core of his character and his public persona as a billionaire business magnate seemed visible at times. Mr. Trump spent the entire time in the courtroom fidgeting last week. He adjusted his tie. He looked at his hands. He leaned back in his chair, then forward, then back. A few times he smoothed the back strands of his hair that spilled over the collar of his suit.

Still, he was attentive at specific points, especially when he seemed to want to convey something to the jurors or the dozens of reporters watching the events in the courtroom.

During jury selection, he looked at all the potential jurors as they walked into the courtroom and turned in his seat to get a better view as they answered the court's biographical questions.

Throughout the trial, Mr. Trump scanned the jurors' faces. He smiled at them a few times.

He was far less concerned when Judge Kaplan described Mr. Trump as having sexually assaulted Ms. Carroll, as had been found by an earlier jury. When Judge Kaplan described that Trump had “forcibly” penetrated Ms. Carroll, who accused Mr. Trump of raping her in a department store dressing room decades ago, the former president made a loud “yech” sound.

Mr. Trump, who sees himself as his own best communicator and defender, sat next to his lawyers during both trials, whispering and writing notes with them. Before Ms. Carroll's lawyers played a video that Mr. Trump posted on Truth Social, Alina Habba, his lead attorney, told the court she wanted the entire video “filed.” Mr. Trump looked at her and said “and played” loud enough for the courtroom to hear. Mrs. Habba immediately added, “And played.”

During Ms. Carroll's testimony, Mr. Trump continually mocked, whispered to his defense team and shook his head more than 20 times as she spoke, including as she described the impact of Trump supporters' negative social media posts. At one point, as she described her response to a message that read, “Put a gun in your mouth and pull the trigger,” Ms. Carroll's voice trembled. Mr. Trump shook his head.

Judge Kaplan, who has a reputation for being strict about what he allows in his courtroom, was often harsh on Ms. Habba, threatening to lock her up on the final day. But despite Mr. Trump's insistence that he is being treated unfairly, Judge Kaplan gave him significant leeway.

Mr. Trump's grumbling during Ms. Carroll's testimony prompted Judge Kaplan to raise the possibility of throwing him out of the courtroom, saying he knew that was what Mr. Trump wanted. “I would really like it. I would love it,” Trump said.

When the judge told Mr. Trump that he apparently could not control himself, the defendant responded: “Neither can you.” There was no further reprimand by the judge, who was clearly aware that the trial was taking place in a charged political context.

Mr. Trump seemed determined to find a way to make his own case, despite the restrictions imposed by the court. At one point, as Ms. Carroll's lawyers played a clip of Mr. Trump calling Ms. Carroll's allegations a “made-up story,” Mr. Trump said “true,” loud enough for the courtroom to hear.

He uttered the word “true” at another point, when one of Ms. Carroll’s lawyers said during closing arguments that Mr. Trump’s legal team wanted the jury to believe he was the real victim.

Testifying in court in the fraud case brought by New York Attorney General Letitia James, Mr. Trump called the trial “very unfair,” said Ms. James was a “political hack” and insulted Judge Engoron by saying that “the fraud lies with the court.”

At the start of the defamation trial against Carroll, Mr. Trump had been warned by his lawyers that Judge Kaplan would tolerate far less in a federal courthouse than Judge Engoron, in part because there was no jury in the New York civil fraud case. Yet Trump still pushed the limits of what he could get away with when he briefly took a stand in his own defense, making comments that the judge quickly expunged from the record.

One of the most dramatic moments in the Carroll case occurred when Ms. Carroll's lead attorney, Roberta A. Kaplan, delivered her closing arguments in which she excoriated Mr. Trump for continuing to defame her client even after pleading guilty at the earlier trial found to have engaged in such behavior.

“Even if you don't like a jury's decision, you are expected to follow it,” Ms. Kaplan said. “Those are the rules. This doesn't depend on your politics, it doesn't depend on who you vote for or whether you support a particular policy or party. We all have to follow the law. However, Donald Trump acts as if these rules and laws simply do not apply to him.”

As Ms. Kaplan continued with her next few sentences, Mr. Trump pushed back his chair, stood up, walked to the back of the courtroom and out the doors. The judge noted that Mr. Trump had left.

Outside the courtroom, his outburst briefly overshadowed the events in media coverage, which may have been the goal. But it was short-lived. Within hours, Trump's new reality was on the news: the jury's verdict that he owes Ms. Carroll $83.3 million.