Seems to me that coming up with a scenario for this is in that very grey area between "possible" and ASB . . But I'm going to think about coming up with something with some potential.
Also, does a coup necessarily need to be by the military? It may be even more ASB if one were to be planned & attempted by someone(s) outside the Military or Government.
Bobinedlaware
Depends on your definition of a coup.
Does stealing the election count? Blackmailing electors? sucessfull rebellion?