However, going down that route would be unprecedented, legal experts say. Lawmakers rarely receive subpoenas from their colleagues, except for when brought up on ethics violations, according to two former House counsels. “To my knowledge, a legislative committee or oversight probe has never done this,” says Stanley Brand, who served as House counsel from 1977 to 1983. The closest parallel may have been in 1972, when a senator’s aide was subpoenaed to testify in front of a federal grand jury in Gravel v. United States about his role in obtaining and arranging the publication of the Pentagon Papers, according to Kimberly Wehle, a law professor at the University of Baltimore.

The lack of historical precedent means that if the committee does attempt to subpoena their colleagues, the move would almost certainly get challenged in court. Republican lawmakers would likely rely on the speech or debate clause of the Constitution—which has been interpreted to provide members of Congress with testimonial privileges as well as criminal and civil immunity for all legislative acts—as part of their legal defense to refuse congressional subpoenas. The text states that “for any Speech or Debate in either House,” Representatives and Senators “shall not be questioned in any other Place.” For example, Brand suggests that conversations among lawmakers about what was going to occur in the House chamber on Jan. 6 would be privileged under the scope of legislative acts.