Federal Judge James Spencer will not let a onetime attorney general become an expert witness in former Governor Bob McDonnell’s trial. McDonnell has wanted Mark Earley to testify about the conduct that federal prosecutors outlined in their indictment of the former Governor. He also asked to have a defense attorney testify about the value of the immunity the prosecutors gave to businessman Jonnie Williams. Williams is a onetime friend of the McDonnell family, and a central figure in the federal government’s case against the former Governor. McDonnell (pictured) and his wife Maureen are scheduled to go on trial late next month.