Any remaining credibility is so miniscule under these circumstances (registered Rat who resigns a White House job in order to work for a man who wants to replace his old boss) that I would require independent corroboration from a credible source.
If he weren't a Kerry campaign employee, though, would we hear about him "taking aim" at the War on Terror? Would the Washington Post care to print it?
I think we all know the answer to that one.