Personal knowledge of the case, the contents of The Men Who Killed Kennedy, and those rational conspiracists I mentioned. I know some of the people who wrote the best conspiracy books, some that even appeared in that show.
I have never believed that a big conspiracy could have been kept quiet. I believe Oswald fired his gun and hit the president. But I wouldn't be surprised if the mother of all coincidences occurred and there were TWO discrete shooters there that day. It's a very simple conjecture that would satisfy a lot of the "what about this" mumbo jumbo.