[x]

The more people in on a conspiracy, the more likely it is that someone will give the plan away. And the further apart the people or groups that make up a hypothetical conspiracy are the harder it will be for them to get together. It's unlikely that such disparate groups would ever have planned an assassination. I suppose it's possible that some enemies of Kennedy in the Mafia might have hired a French assassin, but the authors don't seem to have much credibility.

[mo]

Its called "compartmentalization"..into "cells" -individuals who each have a piece of a job to do blinded to the role of others....which is why IMHO it clearly was an alphabet agency job..