Trump and other co-defendants in the case have said Fulton County District Attorney Fani Willis' relationship with special prosecutor Nathan Wade presents an improper conflict of interest.
Trump, the frontrunner for the 2024 Republican presidential nomination, is accused of illegally pressuring Georgia officials to overturn his 2020 election loss in the state to President Joe Biden.
Trump has pleaded not guilty, along with 14 co-defendants.
A ruling in favor of Trump and his allies could further bog down a complex racketeering case that already faces a potentially long road to trial.
Disqualification of Willis would not necessarily end the case, as she would likely be replaced with a different district attorney.
But this would lead to significant delays, and a new prosecutor could narrow the charges or decide not to pursue the case.
The closing arguments before Judge Scott McAfee on Friday follow a series of evidentiary hearings where Willis conceded having an affair with Wade but accused a defense lawyer of lying about the timing and nature of the relationship.
The affair was first revealed in a January filing by a lawyer for Trump co-defendant Michael Roman, who said it posed a conflict of interest and improperly enriched Wade.
Willis and Wade testified that the relationship did not begin until after Wade was hired, and prosecutors have said the relationship is irrelevant to the case because it did not harm the defendants.
Defense lawyers have accused the prosecutors of lying to the court, saying the relationship began before Wade was hired. In court papers filed last week, Trump's attorney cited location data from Wade's cell phone suggesting he made numerous late-night visits to Willis' home before she appointed him.
Trump is under indictment in three other criminal cases.
He is set to stand trial on March 25 in New York in a case accusing him of illegally covering up hush money payments to a porn star, which could be the only trial he faces before the election.
Trump has also been charged in Washington over his efforts to reverse his 2020 election loss, but that case is paused until the U.S. Supreme Court decides whether he is immune from prosecution over actions he took while in office.
He is also under indictment in Florida over his handling of classified documents upon leaving office. The judge overseeing that case is set to hold a hearing on Friday on Trump's bid to move his May 20 trial date.
Trump has pleaded not guilty in all those cases and says they are part of a politically-motivated plot to undermine his bid for office.
If he wins the presidency, Trump could use his presidential powers to end the Washington and Florida cases because they were brought in federal court.
He would not have the power to stop the Georgia case because it was brought in state court.
(Reporting by Jack Queen; Editing by Noeleen Walder and Daniel Wallis)
By Jack Queen
