"Caesar had his Brutus, Charles the First his Cromwell, and George the Third..."
[Treason!! Treason!!!] ...and George the Third may profit by their example."
That was Patrick Henry, Virginia House of Burgesses, May 30, 1765.
There is one very important difference here when comparing the situation with McKinley: if George Bush is assassinated, we get Dick Cheney.
Acts of God are not acts of man, and certainly not acts of assassins, though heaven knows assassins frequently hear voices (from within and without) who tell them God blesses them. Anyone who believes otherwise has been listening to his own propaganda too long.