Great thread, some fine comments.
There absolutely was a coverup. The day after the assassination, the Asst. Attorney General was on record as saying 'This has to be found to be the work of a lone, crazed gunman'. That was going to be the party line, and the least troublesome to deal with.
Now, what actually happened that they were covering up? That's a bit more tricky.
I'll tell you a story. In the early 80's, a friend of mine ran across the information that there was a book about the Kennedy Assassination that was banned in the US. It couldn't be sold, sent in, and if carried into the USA, it could be seized at border. This got him real interested. Through University libray loan programs, he found that there were 37 listed copies of this book at various major libraries. He tried to get them via loan and found that 35 of the universities had the book on a 'restricted list', that would not even let you see them, if you were just on site. He found two available via the university loan program. One was checked out (and had been for awhile). The only available copy, interestingly, had been misfiled under Drama. He managed to get this copy. On the end papers was the note that the book had been donated to the university by Margaret Chase Smith, noted Republican Senator from Maine. It had '17 of 50' written in by hand, along with an ominous, signed quote from Senator Smith. (I wrote it down, but it has been lost in the intervening time, damnit).
This book was titled 'Farewell America' and it turns out to have been the French Intelligence Services report on the Kennedy Assassination. It details a conspiracy by a bunch of rich businessmen, ex-CIA and ex-FBI members, etc, to take out Kennedy. It names some names. Hmnn.
http://www.jfk-online.com/farewellturner.html
Oswald was almost assuredly a patsy, a designated fall guy. He was probably supposed to be conveniantly taken out shortly after the hit. Ruby was most likely a fallback plan. How much he was involved in everything is guesswork, though I think actually very little. Oswald, imo, was a low level CIA asset. Consider: Here's a military guy, who jumps the iron curtain and defects to the Soviets in the middle of the cold war. He marries a general's daughter. He decides after a few years to come back to the states. His plane fare back is paid by the US Consulate, but he is not arrested for desertion, or even debriefed. He then operates a series of minor pro communist, cuban, etc fronts. Hmnn.
I suspect he was brought into the operation by a former CIA handler, one who was flushed out when Kennedy cleaned house in 1960-61. But Oswald wouldn't have known that.
Speaking of which, the investigator in charge of the Warren Commission was none other than Alan Dulles, the former head of the CIA who was so rancourously fired by Kennedy. Dulles, in a piece by 60 Minutes about the murder of a newsman in Greece, where he was sent in as the American member of the investigation, was quoted there as saying 'Who do we pin this on?'
Evidence disappearing: There's a considerable amound of evidence in this case that disappeared from custody, including such things as a bullet encased in concrete that was thrown out by the FBI, because 'They needed the space.' The brain disappeared. As one forensics conspiracy theorist stated, 'The brain vanished. Why? Because if I had the brain, I could tell you exactly where the bullets came from.'
Who did it? Who killed Kennedy? Hmnn. But it is absolutley obvious that the fix was in from the very beginning to point to the most palatable answer, a lone, crazed gunman. This alone should be reason to be suspicious that that is not the case.
