[azernik]

That was only one of the reasons given in the Federalist Papers for its inclusion; the other is the need to be able to throw around pardons as a bargaining chip in quelling rebellions and civil disorders. The post-Civil-War pardons are a classic example - getting people off the hook for death-penalty treason stuff in order to keep them from going into a new rebellion in a few years - as are the post-Vietnam blanket pardons for draft dodgers.