The biggest change in direction of the USA happened back in June 5, 1968 when a PALESTINIAN IMMIGRANT shot Bobby Kennedy dead and America went into convulsions. I do believe he would have won over Nixon that year. That was the year the”powers that be” decided to wussify and dumb down the American Male.
Then in 1996, a Palestinian immigrant was granted entrance to the USA and the next year, 1997, shot up the Empire State Building observation deck killing one and wounding several others.
It can be argued a bigger change occurred when VP Lyndon B. Johnson had John F. Kennedy brutally murdered in front of hundreds of Americans.
Then RFK had to be killed or he would have exposed LBJ and J Edgar Hoover in their conspiracy. RFK's murder was just taking care of another loose end.