I think he ought to experience an old style public beheading by a hooded executioner wielding an axe.
Make it a bit dramatic with a couple misses and a few non-lethal blows so he can fully appreciates the gravity of the situation.
His head can then be jammed on a pike and displayed a month at a time on the lawn of each state's capitol for all to see what fate awaits all seditious bastards.
That would be splendid.