Oswald in the doorway: the blog of the Oswald Innocence Campaign, by Ralph Cinque

If Oswald knew about the assassination plot, he could have saved Kennedy. If all else failed, he could have gone out onto Elm Street ahead of the limo and with his arms raised so that his empty hands were seen, and he could have yelled, "Stop! Danger! Snipers!" Then he could have pointed to the tops of buildings and to the fence. 

Even if you think a Secret Service agent or policeman would have shot him, it still would have saved Kennedy.

Or, he could have alerted other spectators, telling them: "There are snipers waiting to kill Kennedy. They're high up in the buildings; they're behind the fence. We have to stop them." And here's what they could have done: Oswald and some spectators could have held hands, formed a train, and walked out onto Elm Street. Obviously, you can't hold someone's hand and also hold a weapon. So, there would have been no reason for any Secret Service agent or policeman to shoot at these people. And the snipers weren't going to shoot at them either, having nothing to gain from doing so. It would have brought the motorcade and the assassination to a halt.  

But, Oswald had no explicit knowledge of the assassination. He asked Junior Jarman why people were gathering on the sidewalk, so he didn't even know that the motorcade was driving by the TSBD. Apparently, he didn't see the motorcade route in the newspaper. 

Did he have an inkling, a suspicion that something bad was about to happen or could happen? Maybe, but I don't know. There is a report that someone name "Lee" called the FBI in Chicago to alert them to the plot up there to kill Kennedy. And as a result of that warning, Kennedy's attendance at the Army/Navy football game was cancelled.   

But, if you think it really was Oswald who provided Kennedy with several more weeks to live, there is all the more reason to think that if Oswald knew about the Dallas plot, he would have tried to stop it. And I mean including at peril to himself. 

Oswald didn't know. He had no explicit knowledge of the Dealey Plaza operation. And he had absolutely no reason to arrange for anyone to pick him up at 12:40 that day. And he certainly had no reason to go driving off with Mac Wallace, Frank Sturgis, and David Sanchez Morales, as some contend.