I haven't been to the Texas School Book Depository and haven't been able to check out for myself the view from the window, so I can't offer an informed opinion about whether Oswald could have caused Kennedy's death singlehandedly. But if Oswald was not part of a conspiracy, why was he killed? Jack Ruby's explanation for why he shot Oswald has never been credible. Oswald was killed to protect others.
So says you.