I'll ask again... Based on...? Media speculation? Has any serious person put forth this scenario with any evidence? Or is it just thrown around to stoke some of that "what if" fear?
Based on the current president literally saying that he thought the elections were rigged, and that (during the 2016 campaign) if he lost he might not accept the results and reserved the right to legally challenge them. That would seem to indicate to me that he’s fully prepared to not leave office if he loses and cooks up some scheme as to how the election was invalid.