Steve Hayward at No Left Turns makes a salient point about the Mark Felt revelations:
Whether someone's act is heroic or not depends as much upon why one acts as upon what one does. Doing the right thing for the wrong reason, even if the act requires much courage, is not morally commendable and is certainly not heroic. A man who saves another man's life only because the man who is saved owes his rescuer a large sum of money is not a hero. Saving the man's life is the right thing to do, but the man who does it can claim no virtue in his act. If Mark Felt did indeed help to bring down the Nixon administration only because he was angry at having been passed over for the directorship of the FBI then whatever he is, he's not a hero.
For the Libs, though, whether you're a hero or not seems often to depend only upon whom you're trying to hurt.