Try this scenario:
Burkett claims he has proof that Bush had problems with his TANG record. [Burkett had been pushing this lie for years, but needs proof]. Calls Cleland to tell him he has proof (forged papers that he did or had done). Cleland meets with or speaks to Burkett. Cleland Takes docs back with him to Kerry camp and DNC.
Kerry/DNC not sure if real or fake. Barnes separately says Bush had problems with his TANG record. Barnes tips off Mary Mapes or Rather about what the DNC/Kerry has.
Mapes calls to check on the story and Barnes becomes a "source". Although Kerry/DNC are unsure, Barnes is independently verifing the documents (as to the tone of previous allegations not the veracity of the docs themselves). Barnes tells them Burkett can also verify the docs. Mapes contacts Lockhart and informs him Burkett wants to chat. Lockhart and Burkett chat.
CBS duplicitous in the relationship by wanting the story to be true. They discounted family and others not only because of party affiliation but because Barnes and Burkett supposedly verified the documents. Good enough for them. Back that up with Cleland's words, then CBS figures its true.
Bloggers prove them wrong and CBS wants to back track. DNC/Kerry continue to pressure CBS to stick with story since they're running the Operation Fortunate Son.
The Dam breaks and DNC can no longer control the media cycle. CBS is left to hang and spin in the breeze. Now Burkett will be forced under the bus.
CBS authenticators form a circular firing squad.