[Always Right]

Burkett decides to take matters into his own hands, and provides CBS with copies of the memos. The rest, as they say, is history.

The big hole in your theory is that Burkett, even by CBS standards, would not have been an 'unimpeachable' source. It would take someone of Cleland's stature. Burkett is known to be unstable and a mega-Bush-hater. Besides, I would not buy CBS risking their reputation protecting Burkett. It had to be someone much bigger.

[N. Theknow]

Burkett is known to be unstable and a mega-Bush-hater.

To Dan Rather that is an unimpeachable source.

[Steve_Seattle]

You give CBS too much credit; just because they say they have an "unimpeachable source" doesn't mean it's true.

[TerriHaute]

Besides, I would not buy CBS risking their reputation protecting Burkett. It had to be someone much bigger.

Maybe. Or maybe it was a bluff. I think CBS/Dan didn't want to show weakness or were in denial. It's kinda like arrogant Dan Rather was saying, "My sources are unimpeachable. Don't you know who I am!?? How dare you question my motives."