Sen. Lindsey Graham leaned on a constitutional protection for sitting members of Congress in an effort to keep from testifying before a Georgia grand jury, but legal experts say it’s not clear whether the argument ultimately will work for the South Carolina Republican.

The provision, the Speech or Debate Clause, allows members of Congress to avoid testifying in court about their official actions, among other protections meant to maintain the independence of the legislative branch.

But courts have ruled that the clause has its limits, legal experts said, and that means that Graham’s argument in the case could be a close call.

“I think he will lose, but it is drawing the courts into this muddied area that the Speech or Debate Clause is meant to keep out of the courts,” Josh Chafetz a professor at Georgetown University Law Center who focuses on Congress, said. “I would still think there might be ways in which that would fall in the Speech or Debate Clause.”

Chafetz and others said there’s no previous case quite like Graham’s, meaning the outcome of his case could shape how and when members of Congress go into the courts to try to enforce the clause.

A Georgia state prosecutor, Fani T. Willis, convened a grand jury to investigate former President Donald Trump’s effort to overturn his election loss in the state in 2020, and sought Graham’s testimony about calls he made to Georgia Secretary of State Brad Raffensperger and Raffensperger’s staff in 2020 as well as any communications he had with others setting up those calls.

Graham has said those calls were part of an investigation he undertook as chairman of the Senate Judiciary Committee, and resulted in legislative actions like backing a bill to update the Electoral Count Act, and his vote to certify President Joe Biden as the winner of the 2020 election.

The case gets complicated quickly. Lower courts have a “fairly confused” history of decisions on the Speech or Debate Clause, legal experts said. The Supreme Court has not frequently weighed in on the extent of protections, including whether Graham’s motive for his actions is relevant.

Graham’s attorneys told U.S. District Judge Leigh Martin May on Wednesday that the clause’s protections should block any questions Willis could ask about a pair of calls from Graham about voting practices in the state.

“A Senator’s investigation into a State’s absentee-ballot process and alleged voting irregularities in the State … is quintessentially protected legislative activity, regardless of how often the Fulton County District Attorney wishes to ignore the certification vote, introduction of legislation, and the like,” Graham’s attorneys argued in a brief.

But a similar argument has already fallen short once before in front of the same judge. Last week, May ruled that Graham had to testify before the grand jury.

Graham then appealed the issue to the U.S. Court of Appeals for the 11th Circuit, who gave him a temporary reprieve to hash out the issue again before her.

Investigation vs. influence

Steve Huefner, a law professor at the Ohio State University who practiced law for five years in the Office of Senate Legal Counsel, said appeals courts have drawn a line between a member of Congress conducting an investigation and a member of Congress trying to influence another official.

“It is about whether his actual conduct involved gathering information or asking other government officials to take specific action,” Huefner said.

Huefner said the protection is meant to keep the issue out of the courts, part of the reason why it could be a difficult case.

If Graham used the calls for an investigation, they would be protected, but if he used them to try and influence Georgia officials’ actions, they would not, Huefner said.

“That’s a distinction that may be relatively easy to articulate in the abstract but very hard to draw a line in the specifics,” Huefner said.

Graham, in his court filing, argued that determining whether he had other motives for the call would mean questioning him about the call, which means the court would “require a Senator to lose his immunity in order to gain it.”

Graham also pushed back against an effort to ask about what motive he may have had behind the calls. He argued that “a motive for an action simply does not factor into whether an action is protected by the Speech or Debate Clause.”

Graham cited a 1998 Supreme Court case where a majority of justices found a decision by local officials to eliminate a department was protected activity, as well as a 2005 case from the 11th Circuit, which includes Georgia, which dismissed a suit against state legislators.

The last time an appeals court ruled on the clause for members of Congress, it found prosecutors could use evidence of meetings Sen. Bob Menendez, D-N.J., had with federal executive branch officials in his corruption trial. Menendez was ultimately acquitted at trial.

“That Senator Menendez framed those meetings using the language of policy does not entitle them unvaryingly to Speech or Debate protection,”the U.S. Court of Appeals for the 3rd Circuit wrote.

That appeals court also found that congressional “oversight” of the executive branch is “ambiguously legislative” and that they “may (or may not) be protected legislative acts depending on their content, purpose, and motive.”

The 3rd Circuit’s decision won’t bind May or the 11th Circuit, and Chafetz said the Graham case may be distinct. Chafetz said a court could find that Graham’s calls fall under the privilege, even if they were meant to influence how Georgia handled counting its votes.

“I think what Graham was doing seems to be unambiguously bad,” Chafetz said. “But privileges operate in many cases to protect bad behavior when we think the privilege serves a higher purpose.”