Defense lawyers for Donald J. Trump and his co-defendants in Georgia found themselves frustrated in efforts to extract damaging information from a key witness on Friday, as they sought to disqualify the lead prosecutors accusing Mr. Trump and his allies of a conspiracy to overturn the 2020 election.

The defense is arguing that Fani T. Willis, the Fulton County district attorney, and her office should be disqualified and removed from the prosecution, accusing her of benefiting financially from a romantic relationship with the special prosecutor she hired for the case, Nathan J. Wade.

If the judge removes them, it would delay and potentially derail a proceeding that has major implications for the 2024 presidential election. Here are takeaways from the second day of the misconduct hearing:

The ‘star witness’ for the defense shined no new light on the relationship.

Defense lawyers had high hopes for drawing out damaging testimony from Terrence Bradley, a former law partner of Mr. Wade who also served as his divorce lawyer.

But they were frustrated twice: Mr. Bradley didn’t show up to testify in the morning. Then, once he took the stand in the afternoon, he continued to assert attorney-client privilege over many matters.

That led to repeated sparring between defense lawyers and the district attorney’s office over what questions he could be asked, and — at points — exasperation from a calm but clearly frustrated presiding judge, Scott McAfee.

A defense lawyer used her own cellphone messages to question the key witness.