U.S. Senator Lindsey Graham (R-SC) asks questions to Attorney General Merrick Garland during a Senate Appropriations Subcommittee
U.S. Senator Lindsey Graham (R-SC) asks questions to Attorney General Merrick Garland (not pictured) during a Senate Appropriations Subcommittee, at the Capitol in Washington, DC, U.S., April 26, 2022. Greg Nash/Pool via

An appeals court put on hold U.S. Senator Lindsey Graham's scheduled testimony for Tuesday before a grand jury in Georgia probing efforts by Donald Trump to overturn the former president's 2020 election defeat, with the case returning to a lower court for another look.

A federal judge on Monday had rejected Graham's challenge to the subpoena to testify before the grand jury. Graham, a Republican, had argued his position as a U.S. senator provided him immunity from having to appear before the investigative panel.

Sunday's order by the Atlanta-based 11th U.S. Circuit Court of Appeals comes as a temporary reprieve for Graham who otherwise would have had to testify on Tuesday.

Testimony from Graham, a close ally of Trump, could shed further light on the coordinated effort by Trump's team to reverse the 2020 results.

The appeals court gave Graham a new chance to challenge the subpoena based on protections for lawmakers under the U.S. Constitution's "speech or debate" clause. That provision can protect lawmakers from being compelled to discuss legislative activity.

"The district court shall expedite the parties' briefing in a manner that it deems appropriate," Sunday's order said.

The grand jury wants to question Graham about at least two phone calls he made to Georgia Secretary of State Brad Raffensperger and his staff in the weeks following the November 2020 presidential election, in which Graham explored the possibility of re-examining absentee ballots, according to prosecutors.

The Georgia probe is one among several legal troubles faced by the former president, whose Florida home was searched by federal agents this month and whose role in the Jan. 6, 2021 attack on the Capitol is being investigated separately by a congressional panel.

Trump has falsely claimed that rampant voter fraud caused his loss in Georgia, a battleground state where President Joe Biden's victory helped propel him to the White House.

The special grand jury in Fulton County, Georgia, is undertaking a criminal investigation into alleged wrongdoing. Trump was recorded in a Jan. 2, 2021, phone call pressuring a top state official to "find" enough votes to overturn his loss to Biden in the state. He has denied any wrongdoing.

The grand jury had also subpoenaed members of Trump's former legal team. Rudy Giuliani, Trump's onetime personal lawyer, testified before the special grand jury in Atlanta on Wednesday.