> He in turn gave them to Max Cleland who gave them to
> Mapes and was Gunga Dan’s unimpeachable source.
I still contend that the "unimpeachable" referred to
misreading the White House response when CBS sent them
copies of the memos. The failure to "impeach" the memos
made them "unimpeachable" - it was seen as confirming
them (and by implication, the source).
Whether the "no comment" was a deliberate WH rope-a-dope,
or the WH, unlike CBS, merely wanted to look into them
before making a formal statement, it was the final fatal
after-dinner mint for the skewed scandal gluttons at CBS.
I felt that when Rather said unimpeachable source it was
in the context of where he got the memos.
I could be wrong but that was my understanding.