I have seen speculation here on FR about what might happen if the POTUS were to be assassinated. But what happens if some Antifa nutjob tries and fails? Can the FBI crush the organization?
A tangential question is to potentially prevent such an event, where are the living retired Presidents asking America for normalcy and to respect the Office of, and 45? Where are they to help him? They could make a difference here. That tells me they are all former swamp dwellers.