First off, slander and libel are NOT spoken and written. Libel applies to all published media-- including radio and TV, and probably the Web.
For example, if I hypothetically made a speech to 300 people saying Fenris was a nogoodnik Charlton Heston supporter who buggered dachshunds, he might have a case for slander. If I published that same speech, either during a TV news program, on a radio show, or in a book or on the web, it’d have to be a libel suit. The medium matters.
However, an essential part of any libel and slander suit is defamation of character. I may call Fenris a dachshund-sodomizer, but if people’s opinion of the man improves after this characterization (because really, dachshunds are sexy), then he hasn’t got a case.
There are some other absolute defences against libel: if Fenris really does enjoy playing hide the sausage with the weiner dogs, then once again he can’t sue me for libel either. I’ve got the defence of TRUTH. On the other hand, if I made the whole thing up, well then blind Lady Justice is gonna weigh my balls on the balance in her left hand and skewer them with that sword she carries in her right.
But if I did make it up, and if Fenris is a celebrity, then he’s got an even tougher case. Because he’s so well-known, the impetus would be on the majestic Fenris to prove that my speech, or my publication, actually had an effect to lessen his reputation in the eyes of those-who-adore-the-studly-godhood-that-is-Fenris. If, on the other hand, Fenris is just a lowly, run-of-the-mill doper, he’s got an easier case. Being less well-known, chances are that the only thing people would have heard about Fenris is that he practices bestiality, at least during this hypothetical exercise.
That’s how most libel and slander cases go.
However, in this case, we’re talking about editing an individual’s speech to say something that he didn’t mean. If Mr. Moore had documented my speech, and then altered it to indicate that I was a weiner-dog-felching Charlton Heston worshipper, then I have a case for libel according to the same guidelines.
So, in my IANAL but I am a journalist opinion… Heston could sue-- but since a lot of people thought Heston was a wingnut beforehand, he hasn’t really got a hope in hell of winning.
And for the record-- I know nothing about Fenris’s carnal activities with small dogs. And I don’t want to know either 