Originally Posted by DChristopher

Actually, I think the only historical reason the President was given this power, was to offer pardons to dissenters in order to buy information, or to restore peace and unity after a difficult time.

For instance, after the Civil War Lincoln pardoned Confederate soldiers instead of executing them all for treason.

For another instance, after Vietnam, draft dodgers were pardoned, to restore harmony and reunite the nation after a difficult and controversial period.

As far as I can tell, Clinton's politically motivated pardons, and now Bush's, are a relatively new thing.