Pivotal Hearing Could Stall Georgia Case Against Trump

The three-year long Georgia investigation of Donald J. Trump and his allies for election interference faces its biggest hurdle at a hearing on Thursday, when a judge begins to assess whether the lead prosecutor and her office should be disqualified from the case.

The hearing will delve into a romantic relationship between the two main prosecutors — Fani T. Willis, the Fulton County district attorney, and Nathan J. Wade, whom she hired to run the case. The defense argues that their relationship has created an untenable conflict of interest.

Ms. Willis, Mr. Wade, and a number of others have been subpoenaed to testify at the hearing, including more than half a dozen prosecutors and others who work in the district attorney’s office as well as Mr. Wade’s former divorce lawyer. Ms. Willis’s office has indicated that the prosecutors may call her father, who lives with her in Atlanta, as a witness.

Mr. Trump and 18 other defendants were charged last August with racketeering and a variety of other charges, in connection with a plot to subvert the presidential election results in a number of swing states. Four of the defendants have already pleaded guilty.

The revelations about the affair between Ms. Willis and Mr. Wade surfaced in a legal filing last month from Michael Roman, a former Trump campaign official who is one of the defendants in the Georgia election case.

The argument being made by lawyers for Mr. Roman and other defendants hinges on assertions of a financial conflict. Mr. Wade has been paid more than $650,000 since he was hired in 2021, and during that time he has spent money on joint vacations he took with Ms. Willis. Defense lawyers argue that this creates an incentive for prosecutors to prolong the case, and violates a number of laws and the Georgia bar’s rules of professional conduct.