Duncan and several other Republican elected officials then challenged their subpoenas in court, arguing they’re immune from testifying due to legislative privilege.
Fulton Superior Judge Robert McBurney disagreed and instead set down guidelines for what prosecutors were and were not able to ask lawmakers when they testified.
The judge said the district attorney could not ask about anything related to the conversations Duncan and other legislators had with one another, nor could they inquire about their motivations.
Duncan is at least the fourth figure to receive a subpoena as District Attorney Fani Willis nears a long-awaited decision about whether to bring criminal charges against Trump and others in his inner circle.
Former state Sen. Jen Jordan and former state Rep. Bee Nguyen were both asked to testify before the grand jury, the AJC reported last week. The two Democrats heard falsehood-filled testimony from Rudy Giuliani during state legislative hearings in late 2020.
And independent journalist George Chidi, who stumbled upon a meeting of fake electors at the state Capitol, confirmed that he had also been summoned to discuss his experience.
Duncan, whose subpoena was first reported by CNN, would bring a different perspective to grand jurors. Duncan was once allied with Trump before publicly breaking with the then-president during the 2020 campaign.
He is an outspoken opponent of pro-Trump conspiracy theories and has frequently criticized the “stop the steal” movement that spread through GOP circles after Joe Biden narrowly captured the state in the 2020 presidential race.
As president of the state Senate, Duncan also clashed with key legislators who were among Trump’s most vocal allies in the state. He stripped a trio of lawmakers who backed Trump’s push to overturn the election of leadership posts.
Duncan opted against seeking a second term as Georgia’s No. 2 official, instead promoting a vision of a post-Trump future for the Republican Party in a book he wrote called “GOP 2.0.”
He refused to endorse his successor, former state Sen. Burt Jones, who served as a Trump elector and is closely aligned with the former president. And he said he didn’t vote for Herschel Walker, the Trump-backed U.S. Senate candidate, in last year’s runoff.