The bribery trial for U.S. Sen. Robert Menendez, D-New Jersey, appears more likely to start on its scheduled date of May 6 after one of Menendez's co-defendants on Thursday agreed to waive his ability to call another co-defendant's attorney as a witness.

Attorneys representing Menendez and New Jersey businessmen Wael Hana and Fred Daibes spent several hours at the Manhattan federal courthouse Wednesday discussing a stipulation that would obviate the need for Hana's lead counsel, Lawrence Lustberg of Gibbons PC, to testify at trial.

Lustberg represents Daibes in a separate, older criminal case in New Jersey federal court. Without using Lustberg's name, the Menendez indictment alludes to him in a paragraph alleging that in early 2022, Menendez and Daibes "called Daibes' lawyer to complain that the lawyer had not been aggressive enough in attempting to get Daibes' case dismissed," according to statements made in court and in written filings.

Lustberg's role as a potential witness led to weeks of discussion among the parties about a stipulation regarding his testimony and, if a stipulation could not be reached, the potential for Lustberg to be disqualified from representing Hana at trial.

On Wednesday, U.S. District Judge Sidney Stein of the Southern District of New York presented the parties with a list of more than 50 synonyms for the word "berate"—which had been proposed as one way to describe Menendez's manner of addressing Lustberg on the 2022 phone call—and instructed them to work on a final stipulation in a jury deliberation room.

After two hours of discussions, the parties informed Stein that they had reached an agreement on a stipulation, but Daibes' counsel in the New York case, Cesar de Castro, said his client would not allow him to sign it.

Stein allowed the attorneys to leave the courthouse but instructed them to consider their discussions.

"It really would be a shame for this trial not to go forward on May 6," Stein said.

Daibes evidently changed his perspective on the waiver in the course of the following day, according to two letters filed Thursday afternoon. De Castro did not immediately respond to requests for comment Thursday afternoon.

In the first letter to Stein, prosecutors reported that counsel for Menendez, Daibes and Hana have "have now executed a stipulation" regarding Lustberg's testimony.

The prosecutors requested that all three defendants appear in court to personally confirm they have agreed to the stipulation, but Menendez's lawyers at Paul Hastings wrote on behalf of all three defendants to ask that no such in-person conference take place.

"Sen. Menendez has to be in Washington, D.C., for [S]enate business through this evening and will be unable to make it to New York City by the time of the scheduled conference tomorrow," they wrote. "But in any event, a conference is not necessary: We can represent that each defendant, after consultation with counsel, has authorized counsel to sign the stipulation obviating the need to call Mr. Lustberg and each defendant has confirmed that he waives in full the right to call Mr. Lustberg in the manner described by the Court yesterday and incorporated in the government's letter today."