(Bloomberg) -- US Senator Lindsey Graham can’t delay testifying to a Georgia grand jury investigating efforts by Donald Trump and his allies to overturn his 2020 election, a judge ruled.

US District Judge Leigh Martin May on Friday denied Graham’s emergency motion to put her decision earlier this week ordering him to appear before the grand jury on hold while he appeals.

The judge said a stay wasn’t justified because Graham isn’t likely to succeed in the case, and that delaying the grand jury doesn’t serve the public interest.

“In this context, the public interest is well-served when a lawful investigation aimed at uncovering the facts and circumstances of alleged attempts to disrupt or influence Georgia’s elections is allowed to proceed without unnecessary encumbrances,” the judge said.

One of Trump’s closest allies in the Senate, Graham had been subpoenaed by Fulton County District Attorney Fani Willis to testify about a phone call he made to Georgia Secretary of State Brad Raffensperger. The state election official has said the senator appeared to suggest certain mail-in ballots could be discarded. 

Willis said in an earlier filing that delaying the testimony would prevent the investigation from advancing at a crucial stage.

“Delaying the Senator’s testimony would not simply postpone his appearance, it would also delay the revelation of an entire category of relevant witnesses or information, each of whom would require additional time and resources to secure on behalf of the” grand jury,” Willis said.

Graham’s attorney Bart Daniel declined to comment. He directed call’s to Graham’s senate office.

Graham has denied Raffensperger’s account but argued in court filings he couldn’t be questioned under oath because the call fell under his official duties as a senator and forcing him to testify would violate the Constitution’s separation of powers. 

May rejected Graham’s arguments in her Aug. 15 ruling, finding that the grand jury was investigating post-election conduct that may fall beyond his legislative duties. In her Friday filing, Willis mocked Graham’s claim that he was standing by constitutional principles.

“Senator Graham insists that he seeks to delay his appearance before the Special Purpose Grand Jury not just for his own sake, but also for the sake of the separation of powers, federalism, and ‘for the People,’” Willis said. “The People have requested Senator Graham’s testimony and stand ready to receive it. All that is left is for the Senator to meet them.”

©2022 Bloomberg L.P.