How did CBS know to go to Burkett if the other orgs didn't? Why would they have to go to him if he was handing the docs out to every news outlet? Or, why only a few?
Burkette boasted on the internet that he'd given the information to ex-Senator Max Cleland in the Kerry camp.
My guess is that Cleland was the 'unimpeachable source' that vouched for and then sent CBS, Boston Globe and USA Today to Burkette.
Just a little phone call to point the way without getting the Kerry fingers dirty.