It's only fair that I state my own opinion; there wasn't a conspiracy as Oswald acted alone.
The only 'doubt' I have (and it's only a very slight one) is that Oswald may have said something to someone that with hindsight should have been reported to authorities. The Silvia Odio story and the visits to the embassies in MC are points of concern though I don't believe that if anyone (hypothetically) heard Oswald say that someone should kill Kennedy that that then makes them a conspirator.
In so far as the actual shooting(s) I have no doubt Oswald acted alone and that there was much arse covering going on after the event that has provided scraps of stuff that has fed 55 years of speculation that's resulted in a dog's breakfast of theories.
BTW yesterday I heard a guy in a pub say that the best thing that could happen in the USA right now is for someone to take a potshot at Trump. I didn't report it. I hope that doesn't make me a conspirator at some point.