The Supreme Court on Tuesday cleared the way for Sen. Lindsey Graham (R-S.C.) to face questioning before a grand jury investigating 2020 election interference in Georgia, while emphasizing that the inquiry must abide by constitutional safeguards for lawmakers.

The court’s move was a legal setback for Graham, one of several high-profile allies of former President Trump whom Atlanta-area prosecutors have pursued as part of a probe into the potentially criminal effort to disrupt the 2020 election in Georgia.

The development came in an unsigned, two-paragraph order. Justice Clarence Thomas, who briefly paused the case last week in his capacity as the justice responsible for handling the emergency application, referred the matter to the full court. There were no noted dissents from Tuesday’s order.

Fulton County District Attorney Fani Willis (D) obtained a subpoena for Graham’s testimony in July, before her efforts quickly became ensnared in legal wrangling. 

Willis has indicated her interest in two phone calls Graham made in the weeks after the 2020 election to Georgia’s Republican Secretary of State Brad Raffensperger (R) and members of his staff, as well as any possibly related coordination that may have occurred between Graham and the Trump campaign.

Raffensperger has said Graham suggested that Georgia could invalidate large numbers of mail-in ballots from certain areas. Graham has denied the assertion.

Trump, for his part, in a taped phone call with Raffensperger pressed the top Georgia election official to “find” the roughly 11,000 votes required to overturn Biden’s victory and declare Trump the winner. Raffensperger resisted Trump’s efforts and has rebutted his false claims of election fraud.

Attorneys for Graham did not immediately respond to a request for comment, nor did the Fulton County District Attorney’s Office.

In late July, Graham received a subpoena ordering his appearance before the Fulton County grand jury the following month.

The South Carolina senator quickly asked a Georgia-based federal court to quash the subpoena. Among Graham’s claims was an assertion that the Constitution’s Speech or Debate Clause, which provides protections for lawmakers, should void the subpoena.

The case became quickly bogged down, before an Atlanta-based federal judge in September ruled that Graham could be questioned about his phone calls with Georgia elections officials, within certain limits. 

Specifically, U.S. District Judge Leigh May, an Obama appointee, said Graham would be shielded from inquiries that bear on “protected legislative activity,” including Graham’s information-gathering inquiries about Georgia’s then-existing election procedures and allegations of voter fraud, but that questioning could otherwise proceed.

After an intermediate appeals court affirmed that ruling, noting that Graham could mount objections to specific questions at the district court, Graham turned to the Supreme Court for emergency relief. 

In its Tuesday ruling rebuffing Graham’s request, the Supreme Court reiterated that constitutional guardrails should apply when Graham faces questioning. 

“The lower courts assumed that the informal investigative fact-finding that Senator Graham assertedly engaged in constitutes legislative activity protected by the Speech or Debate Clause, … and they held that Senator Graham may not be questioned about such activities,” the court wrote.

“The lower courts also made clear that Senator Graham may return to the District Court should disputes arise regarding the application of the Speech or Debate Clause immunity to specific questions,” the order continued. “Accordingly, a stay or injunction is not necessary to safeguard the Senator’s Speech or Debate Clause immunity.”

Updated at 3:13 p.m.