U.S. Sen. Lindsey Graham is challenging a subpoena to testify before a special grand jury investigating whether then-President Donald Trump and others broke laws when they tried to overturn Joe Biden’s victory in Georgia. Graham, a Republican from South Carolina, received a subpoena issued on July 26 ordering him to appear before a special grand jury to testify on August 23, his lawyers said in a court filing. Graham is seeking to have the challenge to the subpoena heard in federal court in Atlanta rather than the Fulton County Superior Court judge who oversees the special grand jury. The senator is one of the Trump allies Fulton County District Attorney Fannie Willis wants to challenge as part of her investigation into what she claims was “a multi-state, coordinated plan by the Trump Campaign to sway the November results 2020. elections in Georgia and elsewhere.” Graham had repeatedly said he would fight the subpoena once he received it, which happened last week, according to his lawyers. He has denied meddling in Georgia’s elections. In a court filing last month, Willis, a Democrat, wrote that Graham made at least two phone calls to Georgia Secretary of State Brad Raffensperger and members of his staff in the weeks after Trump’s loss to Biden, asking to be reconsidered some absentee ballots. “to explore the possibility of a more favorable outcome for former President Donald Trump.” In making these calls, Graham “engaged in essentially legislative fact-finding—both to help him shape election-related legislation, including in his role as then-Chairman of the Judiciary Committee, and to help inform the his vote to certify the election,” his lawyers wrote in court on Friday. Graham’s lawyers are citing a provision of the US Constitution that they say “provides absolute protection against investigation into Senator Graham’s legislative acts.” They also argue that “sovereign immunity” prevents a local district attorney from subpoenaing a U.S. senator “to face a state ad hoc investigative body.” And they claim Willis failed to demonstrate “the “extraordinary circumstances” required to order a high-ranking federal official to testify.” Willis’ office will respond in court and expects Graham to testify before the special grand jury, spokesman Jeff Dee Sandys said. Since Graham has been subpoenaed to testify on August 23, his lawyers have asked that his motion to withdraw be considered quickly. The judge granted that request, setting a hearing for August 10. Graham previously filed a lawsuit in federal court in South Carolina to try to stop Willis’ efforts to compel him to testify. Before a judge there could hold a hearing, he withdrew the case and agreed to file any subpoena challenges to the investigation either in state superior court or in federal court in Georgia, according to a court filing. U.S. Rep. Jody Heiss, R-Georgia, filed a federal lawsuit similar to Graham’s after receiving a subpoena to testify before the special grand jury. After hearing arguments from his lawyers and Willis’ office, a federal judge last week declined to quash his subpoena. U.S. District Judge Leigh Martin May, who is also assigned to hear Graham’s challenge, sent the matter back to Fulton County Superior Court, saying there are at least some questions Hice may be forced to answer. If disputes arise over whether Hice is protected under federal law from answering certain questions, he can bring those issues to her to settle, he said. Willis confirmed that the scope of the investigation includes a Jan. 2, 2021 phone call between Trump and Raffensperger, during which Trump urged Raffensperger to “find” enough votes to overturn his loss in the state. “I just want to find 11,780 votes, which is one more than we have,” Trump said during that call. Trump has denied any wrongdoing and has repeatedly described his call to Raffensperger as “perfect.” Willis is also concerned about false allegations of voter fraud made by former New York mayor and Trump lawyer Rudy Giuliani and others during the December 2020 Georgia legislative committee hearings. Jackie Pick Deason, attorney and podcaster based in Dallas, spoke at one of these meetings on December 3, 2020. Willis tries to coerce Deason’s testimony. Because she lives outside of Georgia, Willis must use a process that involves asking a judge in Texas to order her to appear. A judge in New York has already ordered Giuliani to testify next week. In a Texas court filing last week, Deason argued that she should not be ordered to testify. She cited alleged flaws with documents Willis filed for her deposition, argued that a subpoena to appear before a Georgia special grand jury is not recognized in Texas and said the demand for her appearance is based on a false claim that she was a campaign attorney. Trump. She also said it would be unreasonable for her to travel to Atlanta on the days the special jury convenes in August because of work and other obligations. The Morning Update and Afternoon Update newsletters are written by Globe editors, giving you a concise summary of the day’s most important headlines. Sign up today.