Well, you know, all you need is one crackpot to claim something really, really stupid, and then people can jump all over it and lump all conspiracy theories together as if they were one and the same - and the work of crackpots in general. 

If I wanted to protect a conspiracy, I think a good tactic would be to spread really dumb theories so that people could jump all over them - then when one theory emerges which gets close to the truth, whatever that is, the public won't know one theory from the other, and everything will get confused.

Isn't this how the Bush campaign team reacted when Kerry's team challenged Bush's military record?  The Bush team so clouded the matter of military service to the extent that in the mind of the voter, the whole issue became a non-issue.