The documents are fake but we believe them anyway because a week after they were determined to be fake, a little old lady, who we haven't talked to [before or after the documents were determined to be fake], came out and verified the content (while saying that they were absolutely fake).
Somehow, I don't think that is going to fly.
Well, for what it is worth ($0.01), here is my theory:
Who knew about these memos? Only Killian and his secretary, Marian Carr Knox. She claims she has accurate memory of what they contained, contacts someone in the Democrat Party, and then she and a young Democrat operative set out to "reconstruct" the memos. She remembers enough to get a lot of things right, but slips on some details, like the fact of Staudt's retirement 18 months before he was "exerting pressure". The young operative is too young to realize, and Knox is too old to realize, that typing these documents on Microsoft Word is going to be a dead give-away. Then the young operative starts shopping the story around, complete with "documents". Dan Rather thinks he hits paydirt because he believes he got the documents from Killian's secretary, the only person besides Killian who could know about them. That's why he stuck with the story. What I don't know is whether Rather knew the documents were "reconstructed" and went ahead anyway, or just held on to belief in their authenticity because he wanted the story to be true.
As far as the "sweet little old lady" theory goes, I know some 86 year old ladies who are sweet as honey and others who are nasty as vipers. I think we have a viper here, who is mixing fact and hangar gossip and dislike of Bush and an 86 year old's memory from 30 years ago to come up with recollections of memos that are part fact and part fiction.