So this is probably just semantics, but can someone be "pardoned" when they have not yet been tried and found guilty of a crime? Until Snowden is tried and found guilty, he is innocent. What is there to exonerate at present?
It's law rather than semantics. The wikipedia article [0] on Nixon's pardon refers to this specifically:
"After Ford left the White House in 1977, he privately justified his pardon of Nixon by carrying in his wallet a portion of the text of Burdick v. United States, a 1915 U.S. Supreme Court decision which stated that a pardon indicated a presumption of guilt, and that acceptance of a pardon was tantamount to a confession of that guilt."
