If Oswald really had foreknowledge of the assassination, then for doing nothing to save Kennedy, he was guilty of killing him.
This was an emergency, and in an emergency, we are all brothers and sisters. We owe each other everything in an emergency. Oswald owed Kennedy everything- if he knew what was about to happen. He owed it to Kennedy- to save his life.
And if that meant going out into the street to physically block the forward progression of the motorcade, then so be it. If he kept his arms spread overhead and his fingers spaced, showing that he was unarmed, it's unlikely he would have been shot by a Secret Service agent or policeman. And then he could have started yelling,
"Snipers! Snipers! Snipers!"
and, he could have started pointing to the tops of buildings.
Whatever risk there was to himself was well worth taking; he had to take it. Because: who would want to live knowing that you just let Kennedy die? You'd be haunted by it for the rest of your life. It would be the last thought in your mind when you went to bed and the first thought every morning when you woke up- that you did nothing, that, coward that you are, you just let Kennedy be slaughtered in the street.
So, who would want to live that way? You would have no life after that; just a miserable, tortured, painful existence. You would be better off dead; much better off.
So really, it was a no-brainer: if Oswald knew that Kennedy was going to be under attack in Dealey Plaza, he needed to do whatever it took to stop it, at whatever risk to himself that it entailed.
And really, it wouldn't have been that risky because there is safety in numbers. It was a crowded situation. If he blurted to the crowd,
"There are snipers on the rooftops. We have to save him. Join me in the street."
Now, I'm not saying that the whole crowd would have gone out there. Many would have been hesitant. But, don't you think a few would have?
And remember: Oswald wasn't crazy. So, there is no reason to think he would have come across as crazy. Some of the people would have believed him. And they would have joined him out in the street.
And besides, some would have responded by asking him, "What are you talking about?" And then he could have said:
"I am an under-cover intelligence agent, and I'm telling you that there are snipers atop these tall buildings waiting to shoot the President dead. Now come with me. We have to stop it."
Don't you think Oswald would have been able to state that lucidly? Without sounding like a crazed lunatic? I would like to think he could have.
So, Oswald had to help Kennedy; he had to save him- if he knew what was about to happen.
And if it was YOU who knew, would you have acted to save Kennedy, or would you have just watched him die? Have I insulted you by even asking the question? Then why insult Oswald by assuming that he knowingly watched and did nothing?
But, Oswald didn't know. He asked James Jarman why people were gathering on the sidewalk. He honestly didn't know. The night before, his wife told him how much she wished she could see Kennedy, and he said nothing about the President passing his workplace. Driving to work that morning, he said nothing to Frazier about the President passing the building. Nor did Frazier say anything to him. Neither of them knew.
Just put yourself in that situation, where you know what's about to happen, and it's about to go down. What would you do?
Well, give Oswald credit for doing what you would do. That's all I ask. You're a decent human being, right? Well, so was he.