I think he Oswald felt he was a failure and for the United States and for President Kennedy and all of us. He knew he was a failure at everything he tried frustrated with a very sad life but he was a Marxist.
The only time I commit to conspiracy theories is when something way retarded happens. Like Lee Harvey Oswald acting alone.
Postmodernism surely requires an even greater grasp of symbolism as it's increasingly an art of gesture alone.