Military tribunals on civilians can only happen under certain circumstances. Retired Military can be called back up unless they had special considerations in their retirement separation. Once called back up, they can be prosecuted via Military. ( I suspect No Name was handled this way)Milligan case is post Civil War and wraps up some confusion caused by lack of Supreme Court official actions. SC was in part unavailable for emergency due to travel via horse and buggy and Winter Weather ect… ( I still view their lack of action as a full Court as cowardice and failure of their duty) Be weary of this info as this page was edited April of this year and it is afterall Wiki.https://en.wikipedia.org/wiki/Ex_parte_Milligan.
But is basically says Military Courts cannot be used on Civilians as long as there is a functioning civilian Court system. Military can hold a civilian until the civilian can be put back in place.Modern SC has ruled enemy combatants can be tried via military Courts.Furthermore, there is a joint investigation/prosecution of civilians who commit crimes on military installations. https://www.justice.gov/archives/jm/criminal-resource-manual-669-prosecution-military-personnelWe know these crimes have taken place ( at least in part) at military installations because of what is considered a military installation. WH West wing area and residential traveled areas, situation room, AF1, Marine 1, Camp David, Beast, Dining, Library, ect. What this would mean is even if Biden or BHO took a phone call while in any of these Military areas, that is enough to prosecute a civilian involved in the crime in a Military Court if they so choose to assert jurisdiction.
The sheer number of prosecutions would overload an already poorly staffed judicial system so that would require recalling former to active duty. Civilian Lawyers could not engage in the system without having prior experience as JAG