Some people are considered under the law as “defamation proof”; in other words, they have such bad reputations nothing you can say or write about them can injure them. I wonder whether Edwards could be considered “defamation proof” since he is both a lawyer and a politician neither of which are held in high regard by the public as a general matter.
The point, I think, is just to back up Edwards’ claim that it isn’t true. It won’t get as far as an actual suit against the site that published the information: too much truth would come out, on the record and under oath.