The problem with his Wikileaks theory, in my opinion, is that he fails to account for the fact that only ~0.1% of the cables have been released at this stage. The philosophy behind a staggered release? As stated by Wikileaks and Assange, releasing them in waves will allow the public and the press to digest all of the material in a paced, stable manner. This implies that subsequent waves will have important, valuable information that needs to be digested and processed.
I have seen this "US Government is behind cable leak" theory a good deal in the past few days and I do not believe that it holds any water. I think that it's reaching, to be quite frank.