People who want to draw a connection between Oswald's attempts to contact Cuban and Soviet officials in Mexico City and his assassination of JFK have some explaining to do. How could anyone, Oswald included, have known about the golden opportunity Oswald would be dealt to shoot JFK from a perch in the building he was working in. At the time, nobody even knew there would be a motorcade, much less where it would be routed. Had one of the two other sites that were considered for the luncheon been selected, the motorcade wouldn't have passed anywhere near the TSBD.
The assassination of JFK was a crime of opportunity, an opportunity that was dealt to one little man with a cheap foreign made war surplus rifle. The task was not a difficult one and only required one man to carry it out.