You ever been to Dealey Plaza? I have. It is a much smaller area than it appears on film. Much smaller. The grassy knoll that looks so far away on the Zapruder film is like right on top of you. The JFK limo was 265 feet from the Depository window at the moment of the last shot, the head shot. Less than 100 yards. Oswald had a rifle with a 4X scope. The car was moving at 11 miles an hour when it turned the curve, and according to witnesses slowed down as the shots were fired, and was completely exposed. This was not as hard a shot as people make it out to be. And the thing is, the fact that Oswald even qualified at all as a Marine rifleman makes him better than Joe Schmoe coming off the street and trying to do this. FYI, I was a conspiracy buff as a youngster, but reading Posner's book and actually visiting Dealey Plaza and seeing the area and putting 2+2 together in my mind made me do a complete 180 on it.
I also remember when the rifle was tested the scope was not sighted in perfectly, it could have been knocked out by rough handling after the assassination or maybe being out is the reason Oswald made the shot.
I doubt if there was a second shooter that he was anywhere else but right with Oswald.
How do you explain the magic bullet?
I've been to Dealey Plaza and have been up in the book depository building. I've looked out the window where supposedly Oswald shot the President.
How anybody could have leaned out that window and shot at a moving car is beyond me. It's not like the car went under that window. Maybe Oswald was a contortionist.
If Posner's book convinced you you must not have done any prior research into the problems with the Lone Assassin theory. It is filled with mistakes documented elsewhere if you really care.