Donald J. Trump doesn’t change. Judges do.

Two weeks ago, a New York judge, Arthur F. Engoron, permitted Mr. Trump to personally deliver a closing argument in his civil fraud trial as long as he stuck to the facts and avoided a courtroom “campaign speech.” Mr. Trump bulldozed through the restrictions, repeated his familiar claim of a “political witch hunt” and assailed the judge to his face.

Then last week, after a lawyer down the street at the E. Jean Carroll defamation trial complained that Mr. Trump was grumbling “con job” and “witch hunt” loud enough for jurors to hear, Judge Lewis A. Kaplan sternly warned him that, although he had the right to be present, “that right can be forfeited — and it can be forfeited if he is disruptive.”

Ms. Carroll’s lawyers did not find reason to complain again.

The judges’ different approaches to the tempestuous storm that entered their courtrooms — and the different results — could offer lessons beyond the two New York cases. They may provide guidance for the judges set to oversee Mr. Trump’s four potential criminal trials, who will want to keep the 45th president from transforming his legal proceedings into political spectacles.

“The thing you’ve got to do primarily is set rules and enforce them,” said John S. Martin Jr., a former U.S. District Court judge in Manhattan. “I think if the judge is tough and doesn’t back down, Trump will back down.”