Lee Harvey Oswald changed both parties and the country with a single bullet. Killing Kennedy opened the door for LBJ. LBJ ran against Goldwater who was a true Conservative. When LBJ defeated Goldwater that changed the course of the GOP. LBJ then went on to change the course of the Democratic Party.
I think you're giving Oswald --- or whoever he represents --- way too much credit.
Are you saying JFK wouldn't have had the balls to push the CRA like Johnson did? No pun intended there, it's his name...
It was after all JFK's project.
Don't see how Goldwater "changed the course" of the RP either. LBJ had a huge sympathy vote; that was going to be a hill to climb for any opponent. The next round they went back to Nixon -- who was also their candidate in the previous round. Seems more like Goldwater was a temporary deviation.