Hence, the assassination, but in a broader scenario so provocative that it would inspire an official cover up because it would correctly alarm the wider intelligence and national security community. If there was evidence of Cuban and Soviet complicity in the murder of JFK, it would be a classic act of war. The American public would demand retribution, which would lead to a nuclear confrontation. Lyndon Johnson was known to warn of that if the secret of the assassination was revealed, that "Kennedy tried getting Castro, but Castro got him first."
Yet that claim raises the question if Oswald would really be so stupid as to think that he could kill JFK or even just shoot and miss and then be traded and sent to Cuba as if he were a middling Soviet spy who had earned a sunny retirement away from a dodgy Russian wife who would have been allowed to separately go home. To accept that as what Oswald wanted in turn poses issues as to Oswald's improbability as the assassin. He had at best a limited ability as a rifleman and no clear record of recent practice at even stationary targets.
Worse, there is no basis to think that Oswald had the necessary training or experience in hitting moving targets on a downward trajectory through the cover of intermittent leaves and branches. And the official story from the Warren Commission is that Oswald brought the rifle to the Texas School Book Depository on the day of the assassination dissembled and then put it back together shortly before shooting. That alone would tend to degrade the accuracy of Oswald's putative rifle as far as using the scope, leaving him to rely on the iron sights alone. I have never seen a recreation of the shooting that incorporated the scenario of a lightly trained shooter using iron sights on a rifle that had not been test fired after being disassembled.
It is possible that Oswald was a patsy as he claimed, having intended only the discovery of his rifle as a warning to Kennedy. In the event though, the assassination unfolds around Oswald, setting him to a panicked and unplanned flight from the scene.
I could go on, and on, but you get the point: Oswald as the assassin of JFK does not quite add up as to motive or the details of the shooting, with a similar pattern of doubt across almost every important element of the official story. My experience as a lawyer reviewing and arguing for the correctness of criminal convictions on appeal makes me deeply uncomfortable with that.
In valid convictions, the uncertainties diminish on close examination and a solid case emerges, doubts do not multiply as they do with the Kennedy assassination. Under today's standards, the withholding of documents and the poor chain of custody for key pieces of evidence would bar a conviction of Oswald on such a record. There is simply not proof against Oswald beyond a reasonable doubt.
“He had at best a limited ability as a rifleman and no clear record of recent practice at even stationary targets.”
Well, he was a marine, and there actually is testimony that he was practicing at a firing range less than a week before the assassination. Plus there was the General Walker shooting, which I suppose counts as practice as well.