That's a nice link that does a good job of disputing the "huge conspiracy" theory that many people espouse. Again, I believe it's plausible that he acted in concert with another party but the belief that the government and hundreds of people were in on it seems unrealistic to me.

And I may be biased, but the mafia always seemed to be the most realistic of those accused of acting in concert with Oswald. Those involved would keep silent and Oswald, who lost his usefulness after the shooting, was murdered by mob associate Jack Ruby. Those who wonder why they would trust the killing of Oswald to a nobody like Ruby need to remember that the mob would never offer up one of their own in such a "sacrificial lamb" situation. Perhaps the mob offered to help Ruby out with his debt if he rubbed out Oswald.

But like I said earlier, with no hard proof all of this can only be seen as conjecture or theory.