Seeking to painting a picture of the machinations behind what Michael Cohen called a "pressure campaign" to keep him in the Trump fold as investigators closed in on him, prosecutor Susan Hoffinger displayed an email from Michael Cohen's then-legal adviser Robert Costello to Costello's law partner in which Costello wrote that Cohen "continues to slow play us and the president -- is he totally nuts???"

"I am in a golf tournament tomorrow early and again on Sunday. What should I say to this a------ ? He is playing with the most powerful man on the planet," Costello wrote.

"That email certainly speaks for itself, does it not, Mr. Costello?" Hoffiner asked.

"Yes it does," Costello said.

Costello insisted that he was not working to advance Trump's interests and denied the suggestion that he "lost control" of Cohen.

Prosecutors displayed an email from Michael Cohen's then-legal adviser Robert Costello to Costello's law partner Jeffrey Citron from Aug. 8, 2018, in which Costello shared a link to a Fox News story about Rudy Giuliani joining Trump's legal team.

"All the more reason for Cohen to hire me because of my connection to Giuliani, which I mentioned to him in our meeting," he wrote.

In another email, Costello said, "Our issue is to get Cohen on the right page without giving him the appearance that we are following instructions from Giuliani or the President. In my opinion this is the clear correct strategy."

Questioned on the witness stand about that email, Costello told prosecutor Susan Hoffinger that he wanted "to get everybody on the same page because Michael Cohen had been complaining incessantly that Rudy Giuliani was making statements in the press that Michael Cohen didn't approve of."

Costello told Hoffinger he has other emails clarifying that, "which I'd be delighted to tell you."

"That's all right," Hoffinger replied snarkily.

The gallery laughed, prompting a court officer to yell, "Quiet!"

Only a few minutes into prosecutor Susan Hoffinger's cross-examination of Michael Cohen's former legal adviser Robert Costello, their exchanges are already sounding tense.

Hoffinger attempted to confirm that Costello boasted about his relationship with Rudy Giuliani, but Costello denied he did so during his first meeting with Cohen.

"You are quoting from an email that is much later," Costello said.

"I am not quoting from an email," Hoffinger replied.

Hoffinger then asked Costello about his relationship with Giuliani.

"He's been to your wedding?" Hoffinger asked.

"Yes he was," Costello said.

“Let’s get the witness please,” Judge Juan Merchan said after taking the bench.

Michael Cohen's one-time legal adviser Robert Costello entered the courtroom and took the witness stand to continue his cross-examination.

“Good Morning, Mr. Costello. Welcome back,” Judge Merchan said.

Donald Trump said Wednesday that he didn't take the stand in his hush money trial because he didn't agree with the judge's rulings -- and because he was seemingly worried about information that could have come out during cross-examination.

"He made rulings that makes it very difficult to testify," Trump said in an interview on WABC Radio, referring to Judge Juan Merchan. "Anything I did, anything I did in the past, they can bring everything up, and you know what, I've had a great past -- but anything."

"The other reason is because they have no case," Trump said. "In other words, why would -- why testify when they have no case?"

Trump had originally indicated he would testify, saying on April 12 that "I would testify, absolutely." But he subsequently appeared to back away from the idea, falsely telling reporters on May 2 that the limited gag order in the case -- which prohibits extrajudicial statements about witnesses and jurors -- prevented him from testifying.

The next day in court, Judge Merchan directly addressed Trump to clarify that he has an "absolute right" to testify and that the limited gag order does not apply to his statements in court.

"I want to stress, Mr. Trump, that you have an absolute right to testify at trial, if that is what you decide to do after consultation with your attorneys," Merchan said.

-Lalee Ibssa, Soo Rin Kim and Kelsey Walsh