Prosecutors in Atlanta said they need a special grand jury to hear from U.S. Sen. Lindsey Graham, R-South Carolina, because he may be able to provide insight into the extent of any coordinated efforts to influence the results of the 2020 general election in Georgia.

Fulton County Chief Senior Assistant District Attorney Donald Wakeford made that argument Wednesday during a federal court hearing on a request by Graham to quash his subpoena. Brian Lea, an attorney for Graham, argued that Graham’s position as a senator protects him from having to appear before the special grand jury in the investigation into whether former President Donald Trump and his allies committed crimes as they sought to overturn his narrow election loss in Georgia.