I didn't mean to say that Oswald was innocent, rather that he wasn't alone...
If you ever stood in that window in Dallas, you would know that he could have done it all alone just as he almost did to General Walker a few weeks earlier. For anyone who ever handled a deer rifle, it was an easy kill.
A window frame saved Walker. Oswald had a clear shot at Kennedy. He didn't need any help and in his psycho mind, he had all the justification in the world.
Marxism was his motivation, mental illness was the reason. But I'm being redundant.