Nadler pointed to comments Kelly made Monday in which he said he believes assertions reportedly made by former national security adviser John Bolton in a draft of his upcoming memoir. Nadler said Kelly’s comments may signal he has firsthand knowledge of the conduct at issue in Trump’s trial.

“That would seem to indicate that he has knowledge of what Bolton’s testifying to,” Nadler said during the MSNBC interview on Tuesday, naming Kelly as among those on a shortlist of desired witnesses.