I saw something on AHC about JFK that I hadn't seen. They had "evidence" that they had the hit in Chicago and he cancelled on the SS recommendation, then it was in Tampa and Trafficante called it off, and then Marcello got it done.
They showed basically the same setup as Dallas in downtown Chicaago on the route with the unattended open windows and I think the guy bolted and they found his weapons (4 hit man team).
